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From his home on the island of Rhodes in the Aegean, Hipparchus, the greatest of the ancient Greek astronomers, drew up a catalogue of the positions and motions of the objects in the sky. He interpreted the observations as meaning that the Earth was at the centre of everything, and that the planets revolved around the Earth in circles. Claudius Ptolemaeus (more usually called simply Ptolemy), a Greek living in Alexandria in Egypt, observed that the planets did not precisely follow their predicted paths. However, since the circle was regarded as 'perfect' he proposed an 'epicycle' scheme in which each planet pursued a smaller circle about its mean position as it progressed around its orbit. Having studied mathematics at the University of Cracow, the Polish astronomer Nicolaus Copernicus realised in 1507 that the complexity of Ptolemy's scheme could be banished if it was assumed that the planets revolved around the Sun, with only the Moon going around the Earth. Although Copernicus worked out the consequences of this 'heliocentric' theory and informally circulated it to colleagues, it was not formally published until his death in 1543, as De Revolutionibus Orbium Coelestium. The Danish nobleman Tycho Brahe noted the appearance of a 'new star' in 1572 in the constellation of Cassiopeia. It appeared as bright as the planet Venus for three weeks, but slowly faded and finally disappeared from sight a year later. When Brahe reported his observations in a short book De Nova Stella, King Frederick II of Denmark was so impressed that Brahe was assigned the small island of Hven in the channel between Copenhagen and Helsingfors to enable him to establish an 'observatory' to undertake a systematic study of the motions of the planets. As optics had not yet been invented, Brahe developed and refined a wide variety of instruments designed to give accurate measurements of the positions of objects in the sky. In the observatory, which Brahe had named Urania, he had a live-in staff of technicians to assist him with observations. As the work progressed, Brahe received a stream of visiting dignitaries and fellow celestial observers, but when Christian IV assumed the throne support for the project ended. In 1599 Brahe relocated to Prague and continued his work under the patronage of Emperor Rudolph II of Germany. When Brahe died in 1601, his priceless archive of observations passed to Johannes Kepler, who had, towards the end, served as his chief assistant. At that time, there was no clear distinction between astronomy and astrology, and to supplement his mathematical study of empirical laws of planetary motion Kepler earned his living by casting horoscopes. As an unfortunate sign of the times, Kepler's mother was tried as a witch! In 1687 Isaac Newton published Philosophiae Naturalis Principia Mathematica, promoting his law of Universal Gravitation, from which Kepler's laws followed as a consequence. Brahe had therefore produced a catalogue of exceptionally accurate observations without making any attempt to interpret them, Kepler had provided the empirical analysis without understanding why the planets moved as they did, and Newton had identified the motivating force. Overall, these were remarkable achievements for naked-eye astronomy. Was this article helpful?

A Dictionary of Astronomy (3 ed.) Quick reference ‘An enormous amount of obscure data is satisfactorily explained here’ Times Literary Supplement Over 4,300 entries Compiled with the help of a team of expert contributors under the editorship of renowned author and broadcaster Ian Ridpath, the third edition of this dictionary covers everything from space exploration and the equipment involved to astrophysics, cosmology, and the concept of time. The dictionary also includes biographical entries on eminent astronomers, as well as worldwide coverage of observatories and telescopes. Supplementary material is included in the appendices, such as tables of Apollo lunar landing missions, the constellations, and planetary data, and numerous other tables and diagrams complement the entries. The entries have been fully revised and updated for this edition, and around ninety new entries have been added to reflect the recent developments within the field of astronomy, including Bennu, Euclid, Mars Orbiter Mission, and slowly pulsating B star. A Dictionary of Astronomy is an invaluable reference source for students, professionals, amateur astronomers, and space enthusiasts. A Dictionary of Space Exploration (3 ed.) Quick reference Over 2,300 entries This fascinating and expansive dictionary covers all aspects of space exploration, from A-Train to Zvezda. This jargon-free new edition has been fully revised and updated to take into account the new developments in space exploration on an international scale over the last 13 years, with new entries such as Hitomi, Space X Dragon, and Ariane 5 Rocket. All entries are fully cross-referenced for ease of use. In addition, the dictionary also contains links to over 250 space-related websites, and a comprehensive chronology of space exploration. The entries are supported by over 75 photographs, illustrations, and diagrams. The Oxford Companion to Cosmology Reference library The Oxford Companion to Cosmology is a comprehensive, yet highly accessible, encyclopedic overview of this enduringly popular subject. Its 350+ in-depth entries - ranging from cosmic inflation and dark energy to Higgs boson and neutrinos - both illuminate the ideas behind the current understanding of the universe and outline the fundamental physics from which those ideas emerge. Subjects covered include the structure of the universe, the evolution of galaxies, galaxy clusters, and cold dark matter. It deals with both theoretical ideas, such as alternative cosmologies, as well as the various types of observational evidence, including redshift surveys and cosmic microwave background radiation. Appearing at a time when there is a growing consensus about the origins and development of the universe, centred on the hot Big Bang and the emerging Standard Cosmological Model, it offers an introductory overview of this fundamental issue that brings the reader up to date on current thinking. Extensive cross-referencing and a glossary allow the reader to unravel the ideas behind the terminology, while selected illustrations bring the subject to life. Entry-level web links direct the reader to recommended online resources. Written by established experts in theoretical and observational cosmology, the Companion is an invaluable and authoritative reference resource for students, teachers, science writers, and anyone with a serious interest in cosmology.

Starwatch: A winter parade of planets During this last week of January and first week of February, we have an opportunity to easily see five fellow planets in the solar system at one time, and you don't need a telescope or even a pair of binoculars. Mercury, Venus, Mars, Jupiter and Saturn are all stretched out in an arc from the southeast to the southwestern sky and can easily be seen with the naked eye, even if you have to put up with heavy urban light pollution in your neighborhood. Timing is everything, though. To see all five you need to look about an hour to 45 minutes before sunrise, not much sooner or later. If you look too early they won't all be above the horizon, and if you look too late the morning twilight really starts to kick in. Wait until the first reasonably clear morning, and see if you can spot our fellow solar orbiters. Start out by finding the easiest one and then the most difficult one. Venus is by far the easiest since it's the brightest starlike object in the sky. Because of where Venus is and Earth is in their respective orbits around the sun, Venus is our closest neighbor in the solar system at just over 105 million miles away. It's also the second planet out from the sun. In the pre- to early twilight, Venus will be beaming brightly in the low Wichita Falls southeast sky. As bright as it is, there isn't a whole lot to see on Venus. Even with a larger telescope, it's completely shrouded by a thick and poisonous cloud cover complete with acid rain. Underneath the clouds there's a runaway greenhouse effect on the surface. Temperatures can be up and over 900 degrees Fahrenheit. The most difficult planet to see is Mercury, but it's certainly not impossible. Part of the problem is that it's so low in the sky, barely above the southeast horizon. You really need to look for it no later than 45 minutes before sunrise, or morning twilight will wash it out. Another difficulty is that because it's so low, you need to have a clear shot of the southeast horizon. Close-by trees or buildings could easily block your view of the closest planet to the sun. What will help is that you can use Venus to locate Mercury because they're so close to each other. Mercury is about 12 degrees to the lower left of Venus. Hold your fist at arm's length. At a little more than the width of your outstretched wrist, look for a fairly faint star. That's it. That's Mercury. I sure hope you get to see it. Forget about pointing a telescope at Mercury. It's a very small planet, and it's almost 75 million miles away. On top of all that, it's so close to the horizon that its light has to plow through much more of Earth's blurring atmosphere. Saturn is next in line to the upper right of Venus, roughly 15 degrees away or about a fist width and half an arm's length from the planet named after the Roman goddess of love. Saturn is one of the best telescope targets, if not the best, with its famous ring system and family of tiny starlike moons. Even if you have a smaller scope, it's still fabulous. Presently, Saturn is over 990 million miles away, but in June it will be a little closer at less than 840 million away, and you'll get an even better look through your telescope and be viewing it a lot more comfortably. Next in line in our winter planet parade is Mars. It is about 30 degrees or three of your outstretched fist-widths to the upper right of Saturn. Mars is almost directly above the southern horizon, about a third of the way from the horizon to overhead zenith. Mars isn't as bright as Saturn, but it's still moderately bright with a distinct reddish glow to it. Right now Mars is over 130 million miles away, but Mars is a lot smaller than Earth with a diameter just over 4,000 miles. Earth is almost twice that girth. Because of that, Mars will basically look like a red dot with a few tiny blotches through even moderate to larger backyard telescopes. We'll get a much better look at Mars later this year. In May the Martian planet will be less than 50 million miles away, the closest it's been in a couple of years. Mars will be a much, much better telescope target by then. The final planet in our predawn planet parade is the big guy of our solar system. Jupiter has a diameter of 88,000 miles. It's the second-brightest of the planet parade, and by far it's the brightest "star" you can see in the southwest sky. It's so gargantuan you could line up eleven Earths along its diameter. Through even a small telescope, you can see up to four of its moons on either side of Jupiter that revolve around the planet in periods of two to 17 days. You may even see some of Jupiter's brighter cloud bands that stripe the planet. Jupiter is now a little more than 440 million miles away from Earth, but like Saturn and Mars, Earth and Jupiter are drawing closer to each other as we both circle the sun at our different paces. By early March, Jupiter will be just under 415 million miles away from us. Later on this week Jupiter will have a visitor. The waning full moon will be hanging to the lower right of Jupiter, and on Thursday morning the moon will be just to the left of Jupiter. The moon in its 27.3-day orbit around Earth is constantly migrating eastward among the stars and planets from night to night. Enjoy your planetary parade over the next couple of weeks. What a great way to start your day, spotting fellow passengers in our solar system!

NASA officials announced the selection of OSIRIS-Rex as the next US robotic planetary science mission and which will pave the way for an eventual manned mission to an asteroid. OSIRIS-Rex will be the first US mission to collect and return samples of an asteroid to Earth. OSIRIS-Rex is planned for launch to the near Earth asteroid designated as 1999 RQ36 in September 2016 and will return up to four pounds of prisitine asteroidal material to Earth in 2023. The precious sample would land arrive at Utah’s Test and Training Range in a sample return canister similar to the one for the Stardust spacecraft. “We are absolutely delighted to announce the selection of OSIRIS-Rex,” said Jim Green, director of NASA’s Planetary Science Division, at a briefing for reporters. “This asteroid is a time capsule from the birth of our solar system and ushers in a new era of planetary exploration. The knowledge from the mission also will help us to develop methods to better track the orbits of asteroids.” OSIRIS-Rex is the acronym for Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer. The asteroid is an unchanged remnant from the collapse of the solar nebula and birth of our solar system some 4.5 billion years ago, little altered over time. Asteroid 1999 RQ36 is likely rich in carbon, the key constituent of organic molecules and one of the building blocks of life. Organic molecules have been found in meteorite and comet samples, which indicates that some of life’s ingredients can be created in space. The science team will determine if organics also are present on RQ36. Asteroids like 1999 RQ36 may have seeded Earth billions of years ago with organic molecules that are the building blocks of life and perhaps eventually led to living organisms. Samples from the asteroids may help scientists unlock the mysteries of the origin of life on Earth. Three years after launch, OSIRIS-Rex would arrive at Asteroid 1999 RQ36 in 2020 and study the 1900 foot wide space rock in detail for at least six months of comprehensive surface examinations with four science instruments. The science team will also use the time – perhaps up to one year – to look for the optimal place to touch the surface and collect a sample of at least two ounces of surface material with a robotic arm. “We are bringing back what we believe is the type of material that led to the building blocks of life, that led to us,” said Michael Drake, principal investigator of the OSIRIS-REx mission from the University of Arizona. “We’re going for something rich in organics, which might have had something to do with life getting started.” “OSIRIS-REx will explore our past and help determine our destiny,” said Drake. “It will return samples of pristine organic material that scientists think might have seeded the sterile early Earth with the building blocks that led to life. Such samples do not currently exist on Earth. OSIRIS-REx will also provide the knowledge that will guide humanity in deflecting any future asteroid that could collide with Earth, allowing humanity to avoid the fate of the dinosaurs.” The small asteroid RQ36 has also attracted interest because there is a 1-in-1,800 chance of impacting the Earth in the year 2182. Drake added that the team will carefully practice the sample collection before conducting the actual retrieval of a surface material of a mixture of soil and rocks with a pogo stick like device. He said it would be more like “kissing” the surface than a actual landing of the spacecraft. The sampling device at the end of the robot arm looks like a car air filter. It will haul in the pristine regolith into the sample acquisition mechanism within 5 seconds in a “touch and go” maneuver as the spacecraft slowly descends at 0.1 m/sec. Up to 3 attempts are possible. Check the sampling sequence video below. Because the samples are expected to possess organic molecules, they will be subject to stringent planetary protection protocols. The OSIRIS-REx sample capsule will be stored for analysis at a special curation facility at NASA’s Johnson Space Center in Houston. By returning the asteroid samples to Earth, they can be studied by the most advanced science equipment available. “I think we’ll get some much needed info on the composition and physical properties of asteroid surface material. I’m particularly interested in water content for future resource use. The photos should be spectacular,” said former Astronaut Tom Jones in exclusive comments for Universe Today. “This is a critical step in meeting the objectives outlined by President Obama to extend our reach beyond low-Earth orbit and explore into deep space,” said NASA Administrator Charlie Bolden in a statement. “It’s robotic missions like these that will pave the way for future human space missions to an asteroid and other deep space destinations.” When the mission is complete, the spacecraft is expected to have sufficient fuel reserves to be retargeted to a new destination according to Michael Drake. OSIRIS-Rex is expected to cost $800 million according to Jim Green, minus the cost of the launch vehicle which he said has not yet been determined. This is the third mission in NASA’s New Frontiers Program following the Pluto-Charon mission and the Juno Jupiter Orbiter. Lockheed Martin Space Systems in Denver is building the spacecraft. Overall mission management will be provided by NASA’s Goddard Space Flight Center in Greenbelt, Md.

An eclipse is defined as the obscuring of one celestial body from another. As observed from earth, this occurs in two instances, both involving the earth, our sun and our moon. A solar eclipse occurs when our moon moves in front of the sun and partially or fully obscures the sun. A lunar eclipse occurs when the Earth moves between the sun and our moon, casting a shadow on the moon. For a more scientific explanation, please refer to this link. The transit of a planet occurs when that planet passes between the sun and another planet and only partially blocks the sun. Here on Earth, this can only occur with Mercury and Venus crossing the sun's surface. These are the only two planets whose orbital path is closer to the sun than our own. 1. Lunar Eclipse Photographer, Diana LaBelle captured the following image of a lunar eclipse approaching totality in September 2015. During this eclipse, the moon was in its supermoon phase, nearing the closest approach to earth on its orbital plane. As the earth moves between the sun and the moon, earth-light is reflected back onto the surface of the moon, casting a reddish shadow and creating the "blood moon" effect. The reddish color is caused by a phenomenon known as Rayleigh Scattering which is " dispersion of electromagnetic radiation by particles that have a radius less than approximately 1/10 the wavelength of the radiation". 2. Venus Transit We had the great fortune for a Venus transit to occur within our lifetime and twice in one decade, June of 2004 and 2012. Occurring in pairs less frequently than once a century, the next Venus transit will not be witnessed again on earth until 2117 and 2125. On June 5th 2012 it was supposed to rain all day, and it nearly did. Finally, about 20 minutes into the Venus transit the clouds broke and the sun shone through. During that brief, 30 minute window, John Connors and his daughter recreated a very rare and special moment from eight years previous. John set up his telescope to project the sun with Venus visible as a tiny spot on its surface in exactly the same way he had done it in 2004. In the two images below he has included his daughter Heather's profile at age 12 and again, in 2012, at age 20. 3. Lunar Surprise Kelly Frederick Sweet captured a transit of a different kind on this day in September 2015. Kelly wrote, "...a couple of days before the Eclipse, I sat on my porch with the camera deciding where would be the best place to sit. And of course, because it was the moon, I decided to take a shot. I zoomed in and saw what I thought was a bug on my lens, I quickly realized it was a jet flying in front of the moon and snapped the picture." Standing near an airport runway, It is possible to capture images of airplanes silhouetted on the moon during takeoff and landing. It is much more challenging to predict the trajectory of an airplane at this distance that will allow it to transit the moon. Kelly's experience was certainly unique. 4. Solar Eclipse In 2017 my sisters, Dad and I all drove down to Nebraska from Rochester, MN to witness a total solar eclipse. We set a distance limit and, using weather forecasts and Google Satellite, settled on an old railroad town named McCool Junction which is known as the "Magic City on the Blue". On that day, as the moon crossed in front of the sun the clouds began rolling in, blocking our view almost entirely in the moments before totality. Therefore we were not able to photograph the beautiful diamond ring, the corona or bailey’s beads. But before all became murky we did see an amazing scene. We stared in awe as we watched our small moon slide forward to completely block our massive, life-giving sun. Through all of that cloud cover, in those brief moments of totality, we witnessed magic in the "City on the Blue". The three images below show the sun through different lenses and filters. The leftmost image photographed by my sister, Deb Franzen. Deb was using a zoom lens with a home-made mylar filter. The middle and rightmost images were photographed by myself, Teri Franzen. The middle image was captured using a glass solar filter. The rightmost image was using no filter. Note that it is only safe to view the sun unaided when it is nearly fully blocked by the moon. The coloring in the filtered images is introduced by the filters. 5. Crepuscular Rays On a cloudy day, if you see the sun duck behind clouds as it approaches the horizon, you might be treated to beautiful crepuscular rays. These parallel shafts of sunlight are most visible when the sun is lower in the sky and the contrast between light and dark are more obvious. This stunning image was captured by nature photographer William Thomas. 6. Atmospheric Refraction Driving home from work at night when I lived in Los Angeles I once saw the sun so large that I could detect sunspots across its surface. As the sun approaches the horizon we are seeing it through our own atmosphere which acts a lot like a lens or filter. According to Wikipedia, "Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height." Gina Vaughan captured this beautiful image of sunset in Key West, Florida. 6. Resource Links The following links were referenced within this blog:

Seeing a comet with one’s own eyes is a phenomenal experience no one would want to miss in their lifetimes. So when the C/2019 Y4 (ATLAS) was discovered on December 28, 2019, astronomy experts and enthusiasts turned their heads to the cosmic spectacle and kept an eye on it since. Apparently, the comet—discovered from the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey atop Mauna Loa, Hawaii—will be bright enough for everyone to see, so bright that some even hyped on social media that Comet ATLAS might even rival Venus or even the moon with its brightness! Comet ATLAS’ closest approach on our planet has already been projected—on May 23—and the perihelion, or the comet’s closest approach to the Sun, is on May 31. Its orbit is near-parabolic, meaning it’s a comet with a “very high eccentricity (generally 0.99 or higher) and a period of over 1,000 years” that doesn’t have the right velocity to escape the Solar System. Some experts say Comet ATLAS’ orbit is similar to the famous Great Comet of 1844, leading them to speculate that the two may be pieces of what was once a larger comet. We did not let the chance pass to observe the object, which was touted as “the brightest comet” in 2020. Amid the coronavirus pandemic—and since we’ve already been isolated from the rest of the Abu Dhabi city, we started monitoring C/2019 Y4 (ATLAS) on March 16, 2020. Our first two sessions (March 16 and 19) revealed its bright consolidated coma at magnitude +13.1 to +13.2. But just this April, the chances of seeing Comet Atlas with the naked eye got dim. Experts have found that C/2019 Y4 (ATLAS) is quickly losing its luster. On April 6, the news broke out of its disintegration on the Astronomers Telegram. “[C/2019 Y4 (ATLAS)]showed an elongated pseudo-nucleus measuring about 3 arcsec in length and aligned with the axis of the tail, a morphology consistent with a sudden decline or cessation of dust production, as would be expected from a major disruption of the nucleus,” the astronomers behind the report said. True enough, when Al Sadeem observed Comet ATLAS on April 8 and 9, it has dimmed from +13.6 to +14.1. Other observatories from around the world watching the comet shared the same observation. The apparent fragmentation became more evident on April 14when we imaged the comet again, dimming further to +14.2 and +14.3. “Further observations last April 16-17, 2020 also revealed few more fragments breaking up from the comet slightly resolved while it continues to dim at +14.4-+14.6.” The comet is falling apart because of outgassing, which resulted in an increase in the centrifugal force acting on the comet. Where to look for C/2019 Y4 (ATLAS) If you wish to see the comet before it ends its voyage in space—and if you have the equipment to do so—look for Comet ATLAS in the constellation of Camelopardalis. The ideal time would be from 7:15 PM until 9:30 PM (UAE time). To help you locate it with more precision, you can check out the real-time comet’s coordinates (ephemerides) on this link. Knowing the behavior of the comets, C/2019 Y4 (ATLAS)’s fate shouldn’t have come as a surprise. Even well-known comet expert John Bortlebelieved that ATLAS could be “several magnitudes fainter than we currently assume it to be and may or may not, be large enough to survive perihelion passage.” Whatever happens to the bright Comet ATLAS is still uncertain, but we’ll make sure you’ll not be kept in the dark. Stay tuned on our social media channels (Facebook, Instagram, and Twitter). Until then, clear skies and… stay home, stay safe! View this post on Instagram What a treat—a comet spruces up the beginning of #Spring! Resident astronomer @aldrinb.gabuya captured Comet ATLAS, or C/2019 Y4 last March 19. It was spotted as a faint object on December 28, 2019, but since then, the #comet has been getting brighter very quickly that experts hope it could be seen with the naked eye! A caveat though: a comet’s nature can be tricky. It may fizzle out even before we witness its pizzazz. Crossing our fingers for this spectacle! This photo is in LRGB version. Swipe left to see the animation! ✨ #astronomy #abudhabi #uae #astrophotography #alsadeemastronomy #travel #space #planet #cosmos #sky #middleast #stars #dubai #milkyway #universe #deepsky #nightsky #photooftheday #emirates #photography #instagood #nasa #science #horizon #resesrch #youresa #ferventastronomy Observations were conducted by Al Sadeem Observatory’s resident astronomer Aldrin B. Gabuya using GSO 8” Ritchey-Chreteinmouted on Skywatcher EQ6 pro mount, ZWO1600MC-cool CMOS camera, Meade LX850 16” SCT mounted on Skywatcher EQ8 Pro mount, and SBIG STT-8300MM CCD camera.

Study Identifies Three New Habitable-Zone Super-Earths An international team of astronomers has discovered eight new planets orbiting nearby red dwarf stars, three of which are classified as habitable-zone super-Earths. The study identifies that virtually all red dwarfs, which make up at least three quarters of the stars in the Universe, have planets orbiting them. The research also suggests that habitable-zone super-Earth planets (where liquid water could exist and making them possible candidates to support life) orbit around at least a quarter of the red dwarfs in the Sun’s own neighborhood. These new results have been obtained from analyzing data from two high-precision planet surveys – the HARPS (High Accuracy Radial Velocity Planet Searcher) and UVES (Ultraviolet and Visual Echelle Spectrograph) – both operated by the European Southern Observatory in Chile. By combining the data, the team was able to detect signals that were not strong enough to be seen clearly in the data from either instrument alone. Dr Mikko Tuomi, from the University of Hertfordshire’s Center for Astrophysics Research and lead author of the study, said: “We were looking at the data from UVES alone, and noticed some variability that could not be explained by random noise. By combining those with data from HARPS, we managed to spot this spectacular haul of planet candidates.” “We are clearly probing a highly abundant population of low-mass planets, and can readily expect to find many more in the near future – even around the very closest stars to the Sun.” To find evidence for the existence of these planets, the astronomers measured how much a star “wobbles” in space as it is affected by a planet’s gravity. As an unseen planet orbits a distant star, the gravitational pull causes the star to move back and forth in space. This periodic wobble is detected in the star’s light. The team used novel analysis techniques in squeezing the planetary signals out of the data. In particular, they applied the Bayes’ rule of conditional probabilities that enables answering the question “What is the probability that a given star has planets orbiting it based on the available data?” This approach, together with a technique enabling the researchers to filter out excess noise in the measurements, made the detections possible. Professor Hugh Jones, also from the University of Hertfordshire, commented: “This result is somewhat expected in the sense that studies of distant red dwarfs with the Kepler mission indicate a significant population of small radius planets. So it is pleasing to be able to confirm this result with a sample of stars that are among the brightest in their class.” The new planets have been discovered around stars between 15 and 80 light years away and they have orbital periods between two weeks and nine years. This means they orbit their stars at distances ranging from about 0.05 to 4 times the Earth-Sun distance – 149 million kilometers (93 million miles). These discoveries add eight new exoplanets signals to the previous total of 17 already known around such low-mass dwarfs. The paper also presents ten weaker signals for which further follow-up is necessary. Publication: Tuomi, M., Jones, H. R. A., Barnes, J. R., Anglada-Escude, G., and Jenkins, J. S. 2014. “Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics”, MNRAS, in press. PDF Copy of the Study: Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics Image: University of Hertfordshire - Asteroid 2012 TC4 Will Safely Pass By Earth, Just Above Communications Satellites - Astronomers View Near-Earth Asteroid 2014 HQ124 as it Passes Earth - Hubble Space Telescope Views Dwarf Galaxy NGC 178 - Scientists Find Evidence of ‘Orphan’ Gamma-Ray Bursts - Discovery Provides Clues to How Galaxies and Black Holes Develop Together - Investigating the Mysterious Pops of Light Spotted by NASA Satellite - Early Universe “Warmed Up” Later than Previously Thought - Astronomers Discover a Brown Dwarf with an Extremely Red Appearance - A New Self-Assembly Method for Fabricating Graphene Nanoribbons - New Mosiac of the Moon’s South Pole - Cassini Observations Reveal the Complexity of Hazy Exoplanets - New HiRISE Image Shows a Possible Impact Crater in Icy Terrain - Cassini Spacecraft Views a Sliver of Saturn - New Horizons Captures New Data on Kuiper Belt Object 2014 MU69

Back at the first San Francisco Science Hack Day I wanted to do some kind of mashup involving the speed of light and the distance of stars: I wanted to build a visualisation based on Matt’s brilliant light cone idea, but I found it far too daunting to try to find data in a usable format and come up with a way of drawing a customisable geocentric starmap of our corner of the galaxy. So I put that idea on the back burner… At this year’s San Francisco Science Hack Day, I came back to that idea. I wanted some kind of mashup that demonstrated the connection between the time that light has travelled from distant stars, and the events that would have been happening on this planet at that moment. So, for example, a star would be labelled with “the battle of Hastings” or “the sack of Rome” or “Columbus’s voyage to America”. To do that, I’d need two datasets; the distance of stars, and the dates of historical events (leaving aside any Gregorian/Julian fuzziness). For wont of a better hack, Chloe agreed to help me out. We set to work finding a good dataset of stellar objects. It turned out that a lot of the best datasets from NASA were either about our local solar neighbourhood, or else really distant galaxies and stars that are emitting prehistoric light. The best dataset we could find was the Near Star Catalogue from Uranometria but the most distant star in that collection was only 70 or 80 light years away. That meant that we could only mash it up with historical events from the twentieth century. We figured we could maybe choose important scientific dates from the past 70 or 80 years, but to be honest, we really weren’t feeling it. We had reached this impasse when it was time for the Science Hack Day planetarium show. It was terrific: we were treated to a panoramic tour of space, beginning with low Earth orbit and expanding all the way out to the cosmic microwave background radiation. At one point, the presenter outlined the reach of Earth’s radiosphere. That’s the distance that ionosphere-penetrating radio and television signals from Earth, travelling at the speed of light, have reached. “It extends about 70 light years out”, said the presenter. This was perfect! That was exactly the dataset of stars that we had. It was a time for a pivot. Instead of the lofty goal of mapping historical events to the night sky, what if we tried to do something more trivial and fun? We could demonstrate how far classic television shows have travelled. Has Star Trek reached Altair? Is Sirius receiving I Love Lucy yet? No, not TV shows …music! Now we were onto something. We would show how far the songs of planet Earth had travelled through space and which stars were currently receiving which hits. Chloe remembered there being an API from Billboard, who have collected data on chart-topping songs since the 1940s. But that API appears to be gone, and the Echonest API doesn’t have chart dates. So instead, Chloe set to work screen-scraping Wikipedia for number one hits of the 40s, 50s, 60s, 70s …you get the picture. It was a lot of finding and replacing, but in the end we had a JSON file with every number one for the past 70 years. Meanwhile, I was putting together the logic. Our list of stars had the distances in parsecs. So I needed to convert the date of a number one hit song into the number of parsecs that song had travelled, and then find the last star that it has passed. By the end of the first day, the functionality was in place: you could enter a date, and find out what was number one on that date, and which star is just now receiving that song. After the sleepover (more like a wakeover) in the aquarium, we started to style the interface. I say “we” …Chloe wrote the CSS while I made unhelpful remarks. For the icing on the cake, Chloe used her previous experience with the Rdio API to add playback of short snippets of each song (when it’s available). Here’s the (more or less) finished hack: Radio Free Earth. Basically, it’s a simple mashup of music and space …which is why I spent the whole time thinking “What would Matt do?” Just keep hitting that button to hear a hit from planet Earth and see which lucky star is currently receiving the signal.* *I know, I know: the inverse-square law means it’s practically impossible that the signal would be in any state to be received, but hey, it’s a hack.

With the release of the Star Wars: The Force Awakens teaser trailer, we can see that – yet again – some of the action will take place on Tatooine. After I let out an exasperated sigh – I mean come on, there’s an entire galaxy, several of them, in the Star Wars universe, so why does everything have to come back to this ONE planet? – it got me thinking about the use and depictions of planets in science fiction more generally. Tatooine, like many other planets in Star Wars (and other sci fi), is described as having one one major environmental feature (Tatooine – dry and hot; Degobah – swampy; Mustafar – volcanic; Hoth – ice; Alderaan – mountainous). This depiction of entire planets as having only one major environmental feature is simplistic and plain wrong when it comes to the science. The actual science We have yet to discover any life on another planet from Earth. NASA is currently running the Kepler mission to try and identify possible planets in our Milky Way that could potentially support life. Ideally, they want to find an ‘Earth Twin’ – since this is the only planet we know where life exists, scientists have concluded that the conditions of our planet are necessary components for complex life. These components include water on the surface, a particular atmosphere, and size of the planet. Planets of this kind fall within the ‘habitable zone’ – a certain orbital distance from their sun in which surface water could be found. If the planet’s orbit is too close or too far from the sun, it will either be too cold or too hot to be habitable. Current research does suggest that smaller planets that fall within the habitable zone will tend to have a specific geological feature – i.e. be rocky – but scientists are looking for a planet that mimics Earth, including it’s size. The science fiction In more science fiction terms, we are talking about ‘M Class’ planets in Star Trek. Roddenberry and team were fairly on the money with their system of planetary classification, looking at atmosphere, surface, mantle, planetary core, radiation, and carbon-based life forms. Having said that, Star Trek often continued to fall into the trap of defining an entire planet by one particular environmental feature. On occasion, this was given scientific basis – for instance, the planet Vulcan orbits closer to its sun than Earth, necessarily meaning it is hotter, though still within the habitable zone. While Kepler has identified potentially 2 billion planets in our galaxy that could support life, science fiction writers don’t seem to have incorporated any of the actual science behind habitable planets into their fictional worlds (as a general rule). Far too often in SF, planets are described by ONE feature indicative of that particular planet. This was something that came up again in the supposedly relatively scientifically accurate Interstellar. Planets are often described as being icy, rocky, volcanic, heavily forested, etc. But if science is proposing that habitable planets elsewhere will likely be similar to Earth in most – if not every – way, why would writers simplify the construction of a new world like that? The obvious answer is that it makes creating the setting of the world easier to define and quickly distinguishable from other planets mentioned. Maybe I’m on my own here, being too pedantic about the incorporation of real scientific theory into the science fiction I enjoy, but I don’t care. What I want to see in SF writing is planets with multiple landmasses, or at least giant landmasses that span such a distance that the climate of different regions actually differs. Think about it, Australia is a large continent, and while people might dismiss us as just a big, hot, continent covered in red dirt, that’s not true. Queensland is tropical, WA is dry and hot, Victoria humid, while the ACT and Tasmania can be very cold (and even then, those are highly generalized statements about those states as a whole). Or think about the US, the climate in Texas is very different to the climate in Massachusetts. Is it really unreasonable for an educated reader to expect a little more from their SF writers? I’m not saying they can’t simply focus on one area of a particular planet, as that makes complete sense. If your character is a smuggler, they are obviously going to head to the Mos Eisley like area of the planet, continent, or country. Maybe you are dealing with farmers or street urchins in a city built amongst snowy mountains. That’s fine. There’s no reason why you can’t have a particular environmental feature associated with the region in which your characters are involved. However, please stop characterizing entire planets as ‘snowy’ or ‘arid’. The science suggests that it is far more likely that every truly habitable planet has a combination of many different environmental regions. This is my heartfelt plea to all SF writers out there – whether you are writing novels, short stories, films, or TV – please, please, please think about how your supposed habitable planet might actually exist. Science fiction might allow for a lot of fanciful creations, but it has to be rooted somewhere in the scientific. Otherwise it becomes straight-up fantasy. If you are having characters that are interstellar travelers and you want them to visit a particular kind of geological region, that’s ok, but acknowledge that there might be other parts of that particular planet that aren’t exactly the same as the place your characters are currently situated.

Black holes in dense stellar clusters could combine repeatedly to form objects bigger than anything a single star could produce. When LIGO’s twin detectors first picked up faint wobbles in their respective, identical mirrors, the signal didn’t just provide first direct detection of gravitational waves — it also confirmed the existence of stellar binary black holes, which gave rise to the signal in the first place. Stellar binary black holes are formed when two black holes, created out of the remnants of massive stars, begin to orbit each other. Eventually, the black holes merge in a spectacular collision that, according to Einstein’s theory of general relativity, should release a huge amount of energy in the form of gravitational waves. Now, an international team led by MIT astrophysicist Carl Rodriguez suggests that black holes may partner up and merge multiple times, producing black holes more massive than those that form from single stars. These “second-generation mergers” should come from globular clusters — small regions of space, usually at the edges of a galaxy, that are packed with hundreds of thousands to millions of stars. “We think these clusters formed with hundreds to thousands of black holes that rapidly sank down in the center,” says Carl Rodriguez, a Pappalardo fellow in MIT’s Department of Physics and the Kavli Institute for Astrophysics and Space Research. “These kinds of clusters are essentially factories for black hole binaries, where you’ve got so many black holes hanging out in a small region of space that two black holes could merge and produce a more massive black hole. Then that new black hole can find another companion and merge again.” A simulation showing the dynamics of 50 black holes in the center of a star cluster, where two single black holes eventually form a binary black hole. Video: Northwestern Visualization/Carl Rodriguez If LIGO detects a binary with a black hole component whose mass is greater than around 50 solar masses, then according to the group’s results, there’s a good chance that object arose not from individual stars, but from a dense stellar cluster. “If we wait long enough, then eventually LIGO will see something that could only have come from these star clusters, because it would be bigger than anything you could get from a single star,” Rodriguez says. He and his colleagues report their results in a paper appearing in Physical Review Letters. For the past several years, Rodriguez has investigated the behavior of black holes within globular clusters and whether their interactions differ from black holes occupying less populated regions in space. Globular clusters can be found in most galaxies, and their number scales with a galaxy’s size. Huge, elliptical galaxies, for instance, host tens of thousands of these stellar conglomerations, while our own Milky Way holds about 200, with the closest cluster residing about 7,000 light years from Earth. In their new paper, Rodriguez and his colleagues report using a supercomputer called Quest, at Northwestern University, to simulate the complex, dynamical interactions within 24 stellar clusters, ranging in size from 200,000 to 2 million stars, and covering a range of different densities and metallic compositions. The simulations model the evolution of individual stars within these clusters over 12 billion years, following their interactions with other stars and, ultimately, the formation and evolution of the black holes. The simulations also model the trajectories of black holes once they form. “The neat thing is, because black holes are the most massive objects in these clusters, they sink to the center, where you get a high enough density of black holes to form binaries,” Rodriguez says. “Binary black holes are basically like giant targets hanging out in the cluster, and as you throw other black holes or stars at them, they undergo these crazy chaotic encounters.” It’s all relative When running their simulations, the researchers added a key ingredient that was missing in previous efforts to simulate globular clusters. “What people had done in the past was to treat this as a purely Newtonian problem,” Rodriguez says. “Newton’s theory of gravity works in 99.9 percent of all cases. The few cases in which it doesn’t work might be when you have two black holes whizzing by each other very closely, which normally doesn’t happen in most galaxies.” Newton’s theory of relativity assumes that, if the black holes were unbound to begin with, neither one would affect the other, and they would simply pass each other by, unchanged. This line of reasoning stems from the fact that Newton failed to recognize the existence of gravitational waves — which Einstein much later predicted would arise from massive orbiting objects, such as two black holes in close proximity. “In Einstein’s theory of general relativity, where I can emit gravitational waves, then when one black hole passes near another, it can actually emit a tiny pulse of gravitational waves,” Rodriguez explains. “This can subtract enough energy from the system that the two black holes actually become bound, and then they will rapidly merge.” The team decided to add Einstein’s relativistic effects into their simulations of globular clusters. After running the simulations, they observed black holes merging with each other to create new black holes, inside the stellar clusters themselves. Without relativistic effects, Newtonian gravity predicts that most binary black holes would be kicked out of the cluster by other black holes before they could merge. But by taking relativistic effects into account, Rodriguez and his colleagues found that nearly half of the binary black holes merged inside their stellar clusters, creating a new generation of black holes more massive than those formed from the stars. What happens to those new black holes inside the cluster is a matter of spin. “If the two black holes are spinning when they merge, the black hole they create will emit gravitational waves in a single preferred direction, like a rocket, creating a new black hole that can shoot out as fast as 5,000 kilometers per second — so, insanely fast,” Rodriguez says. “It only takes a kick of maybe a few tens to a hundred kilometers per second to escape one of these clusters.” Because of this effect, scientists have largely figured that the product of any black hole merger would get kicked out of the cluster, since it was assumed that most black holes are rapidly spinning. This assumption, however, seems to contradict the measurements from LIGO, which has so far only detected binary black holes with low spins. To test the implications of this, Rodriguez dialed down the spins of the black holes in his simulations and found that in this scenario, nearly 20 percent of binary black holes from clusters had at least one black hole that was formed in a previous merger. Because they were formed from other black holes, some of these second-generation black holes can be in the range of 50 to 130 solar masses. Scientists believe black holes of this mass cannot form from a single star. Rodriguez says that if gravitational-wave telescopes such as LIGO detect an object with a mass within this range, there is a good chance that it came not from a single collapsing star, but from a dense stellar cluster. “My co-authors and I have a bet against a couple people studying binary star formation that within the first 100 LIGO detections, LIGO will detect something within this upper mass gap,” Rodriguez says. “I get a nice bottle of wine if that happens to be true.” This research was supported in part by the MIT Pappalardo Fellowship in Physics, NASA, the National Science Foundation, the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) at Northwestern University, the Institute of Space Sciences (ICE, CSIC) and Institut d’Estudis Espacials de Catalunya (IEEC), and the Tata Institute of Fundamental Research in Mumbai, India. Publication: Carl L. Rodriguez, et al., “Post-Newtonian Dynamics in Dense Star Clusters: Highly Eccentric, Highly Spinning, and Repeated Binary Black Hole Mergers,” Physical Review Letters, 2018; doi:10.1103/PhysRevLett.120.151101

On Monday something happened in the U.S. that should startle — or at least perplex — anyone who gives it any thought, the full solar eclipse. This has little to do with the sheer visceral experience of being amazed by it, as we must be. Do we take for granted the monumental majesty of these monstrously large heavenly orbs? Are they signs of God? Is it not remarkable that these ever-present objects — though separated by nearly one hundred million miles — should once in a very great while perform this curiously perfect dance? But to what end? So this sort of thing doesn’t happen anywhere else in our solar system. But our planet has just one moon that happens to be just the right size and just the right distance from Earth. But what might make us start to think a bit about this event is that this celestial pas de deux is being performed only for us. Anywhere but here on this planet on Monday, the view of these two objects is nothing special. It is only what we see from our terrestrial vantage point that is special. It’s almost as though what we will marvel at was artfully arranged specifically for our benefit. Which brings us to the curious and startling part of the story. About fifteen years ago an odd idea popped into my head. Google was just a gurgling infant. But I happened to have a sturdy Brittanica nearby and I pulled out a dusty volume and quickly discovered the diameter of the sun. It is precisely 864,576 miles. The diameter of the moon was listed at 2,159 miles. I then looked up the distance from Earth to the sun, which varies slightly, but is generally given as 93 million miles. And then I found the distance from Earth to the moon. That varies slightly too, so the average is given as 239,000 miles. Armed with these four figures, I did some simple math. I divided the sun’s diameter (864,576) by the moon’s (2,159) and got 400.452. If my strange hunch was correct, dividing the distance from the Earth to the sun (93,000,000) by the distance from the Earth to the moon (239,000) should give me something similar. It certainly did. My calculations yielded 389.121. And there it was. I stared at the numbers, amazed. Was the correlation in these ratios mere coincidence? Of course what this all meant was simply that these immemorially ancient and vast objects, though as different in size as a single BB and a super gigantic beach ball — one that was over six feet in diameter — would from our perspective here on Earth seem almost precisely the same size. So if they ever just happened to align in the sky, they would match up perfectly. Not almost perfectly. But perfectly, and bizarrely so. What might be the odds of this just happening randomly? Almost all the planets in our solar system have no moons or many moons (Jupiter has 60) of incredibly varying sizes. So this sort of thing doesn’t happen anywhere else in our solar system. But our planet has just one moon that happens to be just the right size and just the right distance from Earth. I found the precision necessary for all of this unbelievable. The more I thought about it, the more I knew that there was no way this could be a mere coincidence. It seemed almost planned. In fact, it seemed utterly planned, as all things of such precision must be. To bring this closer to home, imagine holding a BB twelve inches from our face and then asking a friend to carry the six-foot diameter beach ball as far down the beach as necessary — until it appeared precisely the same size from our perspective as the tiny BB. Keep in mind our beach ball is six-feet in diameter while a normal large beach ball is less than two feet in diameter. Our friend would have to hike 400 feet before the giant beach ball and the tiny BB matched up in size. That’s about the distance from home plate to the centerfield fence in most major league baseball stadiums. So can the sun’s and moon’s diameters — and distances from Earth — be merely coincidentally matched up this perfectly? Everything about it makes that seem ridiculous. But of course you can decide for yourself. Three thousand years ago a man in Israel wrote: “The heavens declare the glory of God; the skies proclaim the work of his hands.” That man didn’t have a telescope or a Brittanica, but he saw something many of us today still do not see. He saw a God behind it all. It may be true that seeing a Grand Designer behind these breath-taking events requires what we call a leap of faith; but it may also be true that seeing mere coincidence behind them requires an even greater leap of faith. In my mind, much greater. But on Monday, you may be the judge.

A Practical Test for the Central Effect Principle Gravitation Metrics and Hydrogen Atom by Michael George If the Central Effect Principle was to have universality, it must – according to the Principle of Analogy – apply for the Cosmos as a whole as well as to all its subunits, for galaxies, solar systems and planets right down to the atom. So far there is no unified theoretical description of the largest and the smallest. In modern science one got used to divide cognisance: For the macrocosm the general theory of relativity was competent, for the microcosms, however, the quantum theory. As the general theory of relativity is no longer compatible with quantum theory, there is an enormous gap between the image of the macrocosms and that of the microcosms. More precisely: The microcosms cannot be described with the general theory of relativity, and the realisations from quantum theory concerning the microcosms lead to a cosmological picture that is not compatible with the interpretations of general relativity. Let us find out whether we may close this gap. Object of our consideration shall be a hydrogen atom (H). In the periodic table of the elements the H-atom is the simplest atom. It is made up of a nucleus, the proton, and a rotating satellite “shell”, the electron. In the classical concept electrically the nucleus is positively, the electron negatively charged. The hydrogen atom is the smallest system with a centre and a satellite that we know. If such an atom is in a state of relative rest in relation to the Earth’s surface and is “left to itself”, the rotating shell – the electron – is in the basic state. This means that the electron takes on a distinctive “orbit”, being the “lowest”, the relatively closest to the proton. Is the electron now “excited” by being “hit” of light energy (photons), it can jump to the next-higher (next-outward) orbit. But for this there are exactly determined prerequisites. The electron cannot change to arbitrary orbits. Every possible orbit represents a defined energy level, and when the electron shall go to the second orbit – as counted from the centre – a defined amount of electric energy is needed to make this jump possible. This amount of energy may also be called an energy quantum. For this reason, the “allowed” electron orbits are called quantum orbits that from the inside out are named n = 1, n = 2, n = 3 etc. The characteristic result is now that the exciting energy for the “quantum leap” of the electron must be kept the lower the larger the orbit is that it at the moment occupies. Stated differently: The higher the excitement state of the electron, the smaller is the energy necessary for a further orbit jump. This also means that the energy an electron carries is higher the further away it is placed. This context is shown in the following table (energy increase in electron volt eV): |Main Quantum Number n||Energy Increase to n = 1 (eV)| Let us see now what amount of energy is needed to bring the electron from n = 1 (basic state) to n = 2, from n = 2 to n = 3 etc. (referred to n = 0): |Main Quantum Number n||Energy Increase to n=1 (eV)||Energy Requirement (eV)| Let us remember how we approached the question quantum orbits. If the Central Effect Principle should have universal validity, it must also be applicable to the hydrogen atom and to the stimulative behaviour of the electron. So the proton – more exactly: the centre of the proton – should be the singular source of a gravitation field, and the electron would then be the smallest natural satellite in the smallest natural gravitation field. Accordingly should the inertia or contumacy of the electron against an alteration of movement (an orbital or quantum leap) should drop with the square of the orbital radius or proportional to the enlargement of its spherical energy area. This idea does not appear in nuclear physics. For the Coulomb’s Law that is valid there demands the “force-free” rotation of the electron. This law is identical to Newton’s Third Law. Here, too, the “centrifugal force” of the electron annuls the “attractive” effect of the protons. Now we have seen in the large scale that the presumption of a gravitational force in natural gravitation fields is untenable. As we showed, it would then be necessary to postulate that all natural orbit or rotation movement occur force-free. Accordingly there cannot be any force in Nature that causes the rotation or orbit movements of satellites, because centrifugal force and gravitation cancel each other out. This assumption is highly unsatisfactory, and it is one of the curiosities of intellectual history that even the most important minds after Newton would be satisfied with this “black hole of thinking”. The only thinker of the last three hundred years who doubted this stipulation was Ernst Mach. His principle shows in a pellucid fashion that no satellite can be without acceleration. Mach, however, correlated his principle only to “static” straight force connections and not to rotating systems. The Central Effect Principle in contrast shows that the straight “force connection” was a fiction stemming from mechanistic thinking. All natural movement follows a curvilinear track, and all natural movement is accelerated movement. Except for Mach’s principle only the Central Effect Principle contains the basic tenet that there cannot be any force-free movement. We must therefore exclude that the electron travels on force-free orbits. What results may we expect? First of all the inertia of the electron must – as indicated above – sink with an orbital space in the ration of 1 : r². One would then also expect that in the basic state (n = 1) the relatively highest energy input would be required to overcome the contumacy of the electron against a change of orbit to n = 2. With the double distance the contumacy would have to sink to a quarter of the value that is needed for n = 1. If we set the needed energy input for n = 1 in relation to the orbits that follow outwards, the following picture emerges: |Quantum Orbit n||Energy Input (eV)||Ratio||Inertia||Energy Area| |2||3,38||1/4||1/4||4 = 2²| |3||1,5||1/9||1/9||9 = 3²| |4||0,85||1/15,9||1/16||16 = 4²| |5||0,54||1/25||1/25||25 = 5²| The table confirms our expectation completely: The energy requirement of the electron diminishes from track to track exactly following the metric of a gravitation field. In the fifth track the contumacy of the electron is lower than the original state by a factor of 25, and therefore the necessary initiation energy in the fifth track is also smaller by the factor 25 compared to the first track. The track numbers n are identical with the whole-number multiples of the track distance to the proton. The tracks can also be called inertia steps of the electron. Every inertia step corresponds to a rotating energy plane. Thus the electron may be regarded as a spherical energy plane whose inertia diminishes in the reverse ratio to its size. In this way we come to the result that the energy of the electron does not increase with an increasing orbit radius as one must suppose when applying Coulomb’s Law. For the contumacy or inertia of the electron decreases outwards in the same ratio as its electric energy increases. The total energy of the electron is the same in all track states! |Quantum orbit n||Increase of electric energy relative to the next inner orbit |Reduction of inertia relative to Track 1 (in brackets relative to the next inner orbit) |2||1 : 4 = -75 %| |3||Factor 1.185 = + 15.6 %||1 : 9 = -88.9 % (- 15.6 %)| |4||Factor 1.054 = + 5.1 %||1 :16 = -93.75 % (- 5.1 %)| |5||Factor 1.024 = + 2.3 %||1 : 25 = -96 % (- 2.3 %)| |2-5 total||Factor 1.28 = + 21.86 %||Factor -1.28 = – 21.86 %| This allows only one solution: namely to attribute the electron a “composite” energy. The total energy of an electron is then made up of “sluggish” and electric energy. It has as a gravitational rotating as well as an electrically oscillating charge component the ratio of which shifts outwardly in favour of the electric charge component. One cannot doubt that an electron may occupy only certain “discrete” orbits that are in a whole-number relation to each other. This recognition would also be applicable to the inertia behaviour of the electron: It can only appear as electrical energy plane of a defined size and a defined inertia, whereby the inertia is inversely proportional to the increase in size of the plane. The Central Effect Principle may – considering all preliminarity and exemplariness of the presented material – be seen as the only universal theory with which simple motion equations for the behaviour of the macrocosm as well as the microcosm may accurately be described. Thus we may argue that the hydrogen atom represents the smallest natural gravitation field with the smallest natural satellite. The source of the proton vortex field is then the smallest natural singular centre. There are two properties of the atom that demand our special attention. At first the inertia of the proton is higher than that of the electron at rest by a factor of 1833. If following to the analogy principle we apply this ratio of inertia to interplanetary orders of magnitude, we come to the fact that our sun also shows a comparable supremacy towards the planet: Relevant calculations indicate that their gravitation potential is higher by the factor of 1000 than that of all planets combined. With the analogy principle we now assume that neither a random atom nor our solar system are subject to special laws, and so we may conclude that all rotating systems of the cosmos are dominated by a centre whose gravitational supremacy is marked by a factor that lies between 1000 and around 1800. As late as the 1980s a mass concentration was hypothesized at the centre of our galaxy with an estimate 30 million times the mass of our sun. According to the analogy principle, however, we must side with those thinkers who assume at the centre of our helical island of worlds a gigantic Black Hole. So we may assume that the 300 billion suns of our galaxy are dominated by a Black Singularity whose gravitational potential is at least that of 300 billion sun masses multiplied by 1000. The second hallmark of a proton is the – for human comprehension unimaginable – thermo-nuclear potential harboured in that minute nucleus. If we also apply this property following the analogy principle to the sun and to any other centre, we may conclude that the thermic as well as the gravitational potential of a centre of a system must be intimately connected. This post is also available in: German

Hubble views the star that changed the Universe Though the Universe is filled with billions upon billions of stars, the NASA/ESA Hubble Space Telescope has been trained on a single variable star that in 1923 altered the course of modern astronomy. And, at least one famous astronomer of the time lamented that the discovery had shattered his world view. The star goes by the inauspicious name of Hubble variable number one, or V1, and resides two million light-years away in the outer regions of the neighbouring Andromeda galaxy, or M31. V1 is a special class of pulsating star called a Cepheid variable that can be used to make reliable measurements of large cosmic distances. The star helped Edwin Hubble show that Andromeda lies beyond our galaxy. Prior to the discovery of V1 many astronomers, including Harlow Shapley, thought spiral nebulae, such as Andromeda, were part of our Milky Way galaxy. Others weren't so sure. In fact, Shapley and Heber Curtis held a public debate in 1920 over the nature of these nebulae. But it took Edwin Hubble's discovery just a few years later to settle the debate. Hubble sent a letter, along with a light curve of V1, to Shapley telling him of his discovery. After reading the note, Shapley reportedly told a colleague, "Here is the letter that destroyed my Universe." The Universe became a much bigger place after Edwin Hubble's discovery. In commemoration of this landmark observation, astronomers with the Space Telescope Science Institute's Hubble Heritage Project partnered with the American Association of Variable Star Observers (AAVSO) to study the star. AAVSO observers followed V1 for six months, producing a plot, or light curve, of the rhythmic rise and fall of the star's light. Based on this data, the Hubble Heritage team scheduled Hubble telescope time to capture Wide Field Camera 3 images of the star at its dimmest and brightest light levels. The observations are being presented on 23 May at the meeting of the American Astronomical Society in Boston, Mass. (USA). "This observation is a reminder that Cepheid variables are still relevant today," explains Max Mutchler of the Heritage team. "Astronomers are using them to measure distances to galaxies much farther away than Andromeda. They are the first rung on what astronomers call the cosmic distance ladder." Copies of the photograph Edwin Hubble made in 1923 flew onboard space shuttle Discovery in 1990 on the mission that deployed Hubble. Two of the remaining five copies were part of space shuttle Atlantis's cargo in 2009 for NASA's fifth servicing mission to Hubble. Edwin Hubble's observations of V1 became the critical first step in uncovering a larger, grander Universe. He went on to measure the distances to many galaxies beyond the Milky Way by finding Cepheid variables within them. The velocities of those galaxies, in turn, allowed him to determine that the Universe is expanding. "V1 is the most important star in the history of cosmology," says astronomer Dave Soderblom of the Space Telescope Science Institute in Baltimore, Md. (USA), who proposed the V1 observations. The space telescope that bears his namesake continues using Cepheids to refine the expansion rate of the Universe and probe galaxies far beyond Edwin Hubble's reach.Credit: About the Image |Release date:||23 May 2011, 20:00| |Size:||3000 x 2400 px| About the Object |Name:||Hubble's Cepheid, V1| |Type:||Local Universe : Star : Type : Variable| Local Universe : Galaxy : Type : Spiral |Distance:||2 million light years|

In universe spanning more than a billion light-years, distance can't be measured with a ruler. To judge how far away objects are, astronomers must rely on other objects whose properties are already known — such as certain kinds of exploding stars called supernova. New research is shedding light on the identity of one of these "standard candles," so-called because their brightness is standard enough that their true distance can be deduced from it. Astronomers are hoping that analyzing one specific type of supernova explosion will give them a better understanding of how frequently it differs from another type. That, in turn, should allow for even more precise measurements of distance in the universe. One dwarf or two When a compact, dying star known as a white dwarf orbits another star closely enough, its strong gravitational pull can ultimately rip its partner apart. But the massive survivor can pack only so much material onto its surface. When its critical point is reached, it explodes as a Type 1a supernova. These events can be divided into two categories. One involves only the single white dwarf and its victim. The other involves two white dwarfs, with one destroying the other. New research, published in the Aug. 12 issue of the journal Science, takes a look at just how commonplace the single-white-dwarf version of a Type 1a supernova may be. [Video: Supernovas – Destroyers and Creators] When two white dwarfs are orbiting one another and the smaller one moves too close, it is almost instantly torn apart, creating a disk to orbit its destructive companion. Almost immediately, the disk falls onto the remaining star, pushing it over the critical mass threshold and causing an explosion. But when the second star in a pair isn't a white dwarf, things move slower. The stars don't get as close, and tidal forces manage to pull away only some of the gas from the near side of the second star. The white dwarf feeds on the material until it eventually reaches the critical mass, exploding as a supernova. "Both models agree that the explosion is an accreting white dwarf," the lead author of the study, Assaf Sternberg at the Weizmann Institute of Science in Israel, told SPACE.com via email. "The disagreement is on the origin of the accreted material." It is this material that interested Sternberg and his team. When the destroyed star is a white dwarf, the material is quickly consumed, but when it is not, traces of the gas linger even after the explosion. The international team of astronomers used the Keck telescope in Hawaii and the Magellan telescope in Chile to study the sodium in gas clouds around 41 Type 1a supernovas. Sodium is an element found in most stars but not in white dwarfs. From the sample taken, the team determined that at least 24 percent of the explosions did not involve white dwarfs as the companion. This number was a lower limit: Half or even all of the pairings could involve only one white dwarf star. The researchers couldn't specifically target which explosions contain white dwarfs and which do not. Instead, they looked for a distribution. They found more systems with sodium than would be found if there were an equal number of double-white-dwarf and single-white-dwarf systems. Josh Simon, of the Carnegie Institute, explained how this event helps determine distances in the universe. "If you know that the light bulb is 60 watts, then you can figure out how far away the light is from you by measuring how bright it looks," he told SPACE.com by email. But the second star in the set could be a number of things. Simon likened the different pairings to light bulbs of varying wattage. "You can't tell the difference between a 50-watt bulb nearby, a 60-watt bulb a bit further away, or a 100-watt bulb even farther away than that," Simon said.

There’s something new to look for in the heavens, and it’s called a “synestia,” according to planetary scientists Simon Lock at Harvard University and Sarah Stewart at the University of California, Davis. A synestia, they propose, would be a huge, spinning, donut-shaped mass of hot, vaporized rock, formed as planet-sized objects smash into each other. And at one point early in its history, the Earth itself was likely a synestia, said Stewart, who is a professor in the Department of Earth and Planetary Sciences at UC Davis. Lock and Stewart describe the new object in a paper published May 22 in the Journal of Geophysical Research: Planets. Lock, who is a graduate student at Harvard, and Stewart study how planets can form from a series of giant impacts. Current theories of planet formation hold that rocky planets such as the Earth, Mars and Venus formed early in the existence of our solar system as smaller objects collided with each other. These collisions were so violent that the resulting bodies melted and partially vaporized, eventually cooling and solidifying to the (nearly) spherical planets we know today. Lock and Stewart are particularly interested in collisions between spinning objects. A rotating object has angular momentum, which must be conserved in a collision. Think of a skater spinning on ice: If she extends her arms, she slows her rate of spin, and to spin faster she holds her arms close. Her angular momentum is the same. Now consider two ice skaters turning on ice: if they catch hold of each other, the angular momentum of each adds together, so their total angular momentum must be the same. Lock and Stewart modeled what happens when the “ice skaters” are Earth-sized rocky planets colliding with other large objects with both high energy and high angular momentum. “We looked at the statistics of giant impacts, and we found that they can form a completely new structure,” Stewart said. The researchers found that over a range of high temperatures and high angular momentum, planet-sized bodies could form a new, much larger structure, an indented disk rather like a red blood cell or a donut with the center filled in. The object is mostly vaporized rock, with no solid or liquid surface. They have dubbed the new object a “synestia,” from “syn-,” “together” and “Hestia,” Greek goddess of architecture and structures. A new type of structure The key to synestia formation is that some of the structure’s material actually goes into orbit. In a spinning solid sphere, every point from the core to the surface is rotating at the same rate. But in a giant impact, the material of the planet can become molten or gaseous and expands in volume. If it gets big enough and is moving fast enough, parts of the object pass the velocity needed to keep a satellite in orbit, and that’s when it forms a huge, disk-shaped synestia. Previous theories had suggested that giant impacts might cause planets to form a disk of solid or molten material surrounding the planet. But for the same mass of planet, a synestia would be much larger than a solid planet with a disk. Most planets likely experience collisions that could form a synestia at some point during formation, Stewart said. For an object like the Earth, the synestia would not last very long — perhaps a hundred years — before it lost enough heat to condense back into a solid object. But synestias formed from larger or hotter objects such as gas giant planets or stars could potentially last much longer, she said. The synestia structure also suggests new ways to think about lunar formation, Stewart said. Earth’s moon is remarkably similar to Earth in composition, and most current theories about how the moon formed involve a giant impact that threw material into orbit. But such an impact could have instead formed a synestia from which the Earth and moon both condensed. No one has yet observed a synestia directly, but they might be found in other solar systems once astronomers start looking for them alongside rocky planets and gas giants. The work was supported by NASA and the U.S. Department of Energy. Audio: Synestia, A New Planetary Object

The only natural satellite of the Earth and the 5th largest among all the satellites in the solar system, the Moon is a great celestial body in our solar system which the universe has bestowed upon us. With an appearance that is calm and ever-fascinating, Moon has been a subject matter of interest for many since the ancient times and has a strong relevance in our mythologies, cultures, arts and calendars. The day Galileo observed Moon closely through his telescope; he would not have imagined that one day a human would set foot on the grounds of this glowing element in the sky above our heads. But then, he may not have imagined lots of things science is discovering about the Moon today. Here is an entire section to feed your curiosity for the Moon and related facts. Take a glance! Distance From Sun: 147 million kilometres Average Distance From Earth: 384,400 km Mean Radius: 1737.5 km Mean Circumference: 10,917.0 km Volume: 21,971,669,064 km3 Mass: 7.34 x 1022 kg Density: 3.344 g/cm3 Surface Area: 37,936,694.79 km2 Surface Gravity: 1.624 m/s2 Length of Day: 27.322 Earth days Length of Year (Orbital Period): 0.074803559 Earth years Average Orbit Velocity: 3,680.5 km/h Orbit Inclination: 5.16 degrees Orbit Circumference: 2,413,402.16 km Average Temperature: -233°C/123 °C (Min/Max) Interesting And Fun Facts About Moon - It is believed that Moon was formed when a Mars-sized body collided with the Earth about 4.5 billion years ago. The debris of this collision from both bodies got accumulated to form the Moon, the natural satellite of Earth. - Moon doesn’t have an atmosphere so a number of asteroids, meteoroids and comets have been crashing into it since its formation. The rain of these celestial bodies has made the surface a pile of heavy boulders to powder over some billion years. - The surface of Moon is two-layered. The Upper layer known as lunar regolith, is a rubble pile of charcoal-gray, powdered dust and rocky wreckages while the Lower Layer known as the megaregolith, is the region of fractured bedrock. - The Nectaris and Imbrium basins and the craters Erathosthenes and Copernicus are the impact structures used to classify objects on the Moon as per the time of their existence. - Because of being a differentiated body, the Moon has geochemically different core, mantle and crust. While its core, with a radius of 240 km, is made up of solid iron whereas its crust, 50 km thick on average is made up of pyroxene, ilmenite, magnetite, and olivine. - Around 30,000 craters are estimated to be located on the near side of the Moon alone. All these craters are wider than 1 km. - It is estimated that around 14,000 km2 of Moon’s surface lies in permanent darkness. This region is also referred to as the ‘Dark Side of the Moon’. - Water in liquid form is not known to exist on the surface of the Moon. However, Chandrayaan-1 spacecraft, in 2008, has confirmed the presence of surface water ice. - Because of its proximity to the Earth, Moon appears to be the brightest object around, standing second to the Sun. In fact, Moon reflects light of the Sun and has none of its own (for it doesn’t generate energy on its own). In actuality, Moon has a dark coal-like surface. - From the Earth, the Sun and the Moon look exactly of the same size. However, the sun is about 400 times larger than the Moon but sun is also 400 times farther from the Earth! - Moon is about a quarter of diameter of Earth. And taking into consideration the size of the related planet i.e. the Earth, the size of the Moon makes it the largest natural satellite of any planet in the solar system,. - Moon is the second densest natural satellite of the solar system, lagging only behind Io, the innermost Galilean moon of the planet Jupiter. - Galileo Galilei was the first person to make a scientific observation of the Moon, using a telescope. - Moon is called the ‘Moon’ because we did not know about other moons in the solar system until Galileo Galilei discovered four moons orbiting the Jupiter in 1610. Thereafter, all the moons of other planets then were given names, so as not to confuse each with other moons. - The first visitors to the Moon are the USSR’s spacecrafts Luna 1 and Luna 2, who first visited it in 1959. Later, a number of U.S. and Soviet robotic spacecrafts were also sent to the Moon. - Moon is the only celestial body in the entire solar system visited by humans. It was first stepped foot on by Neil Armstrong and Edwin ‘Buzz’ Aldrin on 21st July 1969. Over the next three years, ending in 1972, a total of 12 people set foot on the surface of the moon, the last one being Eugene Cernan. - The gravity of the Moon is just 17 percent than that of the Earth, so, if you weigh 60 kg on the Earth, you will weigh just 10 kg on the Moon! - This same gravitational force of the Moon is a cause of the ocean tides and the minute lengthening of day on the Earth. - During a total solar eclipse, the Moon fully covers the sun, as seen from Earth. - Moon, by moderating Earth’s wobble on its axis, has been stabilising the climate of the planet Earth from billions of years. - Since the time taken in rotation on their respective axis is same for the Earth and the Moon, we always tend to see only one side of the Moon. This is called synchronous rotation of the Earth and the Moon. - The dark features of the Moon are known as ‘Maria’ (referring to ‘sea’ in Latin), while the light features are called as the ‘Highlands’. These dark features are the impact basins which are believed to have been filled with lava about 4 to 2.5 billion years ago. - The lunar crust of the Moon has influences of magnetic field whose source is yet unknown, as there is no internally generated magnetic field on it. - Moon is drifting away from the Earth at a rate of 4 centimetres a year. However, it is expected that in the next 50 billion years it will stop drifting and both, the Earth and the Moon will be tidally locked to each other. - NASA is planning to set up a permanent research station at Moon! - The Outer Space Treaty which is the basis of the international space law allows all nations to explore Moon for peaceful purposes.

Turns out, we may not know our extragalactic neighbors as well as we thought. One of the promises held forth with the purchase of our first GoTo telescope way back in the late 1990s was the ability to quickly and easily hunt down ever fainter deep sky fuzzies. No more juggling star charts and red headlamps, no more star-hopping. Heck, it was fun to just aim the scope at a favorable target field, hit ‘identify,’ and see what it turned up. One of our more interesting ‘discoveries’ on these expeditions was NGC 2419, a globular cluster that my AstroMaster GoTo controller (featuring a 10K memory database!) triumphantly announced was an ‘Intergalactic Wanderer…’ Or is it? The case for NGC 2419 as a lonely globular wandering the cosmic void between the galaxies is a romantic and intriguing notion, and one you see repeated around the echo chamber that is the modern web. First observed by Sir William Herschel in 1788 and re-observed by his son John in 1833, the debate has swung back and forth as to whether NGC 2419 is a true globular or—as has been also suggested of the magnificent southern sky cluster Omega Centauri—the remnant of a dwarf spheroidal galaxy torn apart by our Milky Way. Lord Rosse also observed NGC 2419 with the 72-inch Leviathan of Parsonstown, and Harlow Shapley made a distance estimate of about 163,000 light years to NGC 2419 in 1922. Today, we know that NGC 2419 is about 270,000 light years from the Sun, and about 300,000 light years from the core of our galaxy. Think of this: we actually see NGC 2419 as it appeared back in the middle of the Pleistocene Epoch, a time when modern homo sapiens were still the new hipsters on the evolutionary scene of life on Earth. What’s more, photometric studies over the past decade suggest there is a true gravitational link between NGC 2419 and the Milky Way. This would mean at its current distance, NGC 2419 would orbit our galaxy once every 3 billion years, about 75% the age of the Earth itself. This hands down makes NGC 2419 the distant of the more than 150 globular clusters known to orbit our galaxy. At an apparent magnitude of +9 and 6 arc minutes in size, NGC 2419 occupies an area of the sky otherwise devoid of globulars. Most tend to lie towards the galactic core as seen from our solar vantage point, and in fact, there are no bright globulars within 60 degrees of NGC 2419. The cluster sits 7 degrees north of the bright star Castor just across the border of Gemini in the constellation of the Lynx at Right Ascension 7 Hours, 38 minutes and 9 seconds and declination +38 degrees, 52 minutes and 55 seconds. Mid-January is the best time to spy NGC 2419 when it sits roughly opposite to the Sun , though June still sees the cluster 20 degrees above the western horizon at dusk before solar conjunction in mid-July. We know globular clusters (say ‘globe’ -ular, not “glob’ -ular) are some of the most ancient structures in the universe due to their abundance of metal poor, first generation stars. In fact, it was a major mystery up until about a decade ago as to just how these clusters could appear to be older than the universe they inhabit. Today, we know that NGC 2419 is about 12.3 billion years old, and we’ve refined the age of the Universe as per data from the Planck spacecraft down to 13.73 (+/-0.12) billion years. What would the skies look like from a planet inside NGC 2419? Well, in addition to the swarm of hundreds of thousands of nearby stars, the Milky Way galaxy itself would be a conspicuous object extending about 30 degrees across and shining at magnitude -2. Move NGC 2419 up to 10 parsecs distant, and it would rival the brightness of our First Quarter Moon and be visible in the daytime shining at magnitude -9.5. And ironically, another 2007 study has suggested that the relative velocity of Large and Small Magellanic Clouds suggest that they may not be bound to our galaxy, but are instead first time visitors passing by. And speaking of passing by, yet another study suggests that the Milky Way and the Andromeda galaxy set on a collision course billions of years hence may be in contact… now. Mind not blown yet? A 2014 study looking at extragalactic background light during a mission known as CIBER suggests that there may actually be more stars wandering the universe than are bound to galaxies… But that’s enough paradigm-shifting for one day. Be sure to check out NGC 2419 and friends and remember, everything you learned about the universe as a kid, is likely to be false.

Asteroid Hyalosis B Scan commonuspictures Scan Asteroid B Hyalosis We found 22++ Images in Asteroid Hyalosis B Scan: Top 15 pages by letter A - Astronomy Cosmology - Apollo 5 Car - Astronomical Chart with Planets and Stars - Are Habitable Planets Likely - Astronomy Merit Badge - Apollo 15 Moon High Resolution - Astronaut by Shuttle - Asteroid by Moon Tonight - All Apollo Mission Crew - Animals On Other Planets - Apollo Spacecraft Interior Plastic - Allen Bradley MCC Wiring Diagrams - Astronaut DJing - Asteroid 2030 - Astronaut in Space Hair About this page - Asteroid Hyalosis B Scan Asteroid Hyalosis B Scan Discover Images Retina Image Bank Hyalosis Asteroid Scan B, Asteroid Hyalosis B Scan Asteroid Hyalosis B Scan Asteroid Hyalosis Scan B, Asteroid Hyalosis B Scan Application Of Transpupillary Thermotherapy In A Patient Hyalosis B Asteroid Scan, Asteroid Hyalosis B Scan Asteroids B Scan Retina Image Bank Hyalosis B Asteroid Scan, Asteroid Hyalosis B Scan Diagnostic Ophthalmic Ultrasound Radiology Key Asteroid Hyalosis B Scan, Asteroid Hyalosis B Scan Article Fulle Text B Asteroid Scan Hyalosis, Asteroid Hyalosis B Scan Article Fulle Text Hyalosis Asteroid B Scan, Asteroid Hyalosis B Scan H4321 23 Crystalline Deposits In Vitreous Decision B Hyalosis Asteroid Scan. Interesting facts about space. The sunlight that penetrates through the transparent crust helps the growth of vegetation in the caves to a substantial extent. However sunlight is not the main light source in the caves. The types of vegetation found in the moon are markedly different from the ones on earth. The plants commonly seen in the caves are quite short and look very much like the miniature trees, bushes and shrubs grown using Japanese "Bonsai" techniques. and here is another The elders collectively believed that the people could well get along without modernity. The moon people value simplicity over comfort, convenience and leisure. Their lifestyle was based on a deliberate balance of avoiding a pleasure world while maintaining self-sufficiency. The networks of elders who have the responsibility to take decisions are not rulers of any kind. Triton is unique among our Solar System's moons of planetary mass. This is because its orbit is retrograde to Neptune's rotation and inclined relative to Neptune's equator. This suggests that Triton was not born in orbit around Neptune, but was instead snared by the giant planet. - Triangulum Galaxy Seen From Earth - Written Report 5th Grade Solar System - Space Science Clipart - Neil Armstrong Farm - Solar System Project - How Big Was Asteroid That Landed On the 2019 Is - NASA New Horizons Mission to Pluto - Pioneer Space Missions - Saturn Cassini Satellite - Cool Dwarf Planet - Does Neil Armstrong Live in Ohio - NASA Ganymede - 2036 Asteroid Countdown - F-Sim Space Shuttle - Blue Nebula Background The Kuiper Belt, sometimes called the Edgeworth-Kuiper Belt, is a region located in our Solar System's outer limits beyond the realm of the eight major planets. It extends from the orbit of Neptune to approximately 50 AU. Neptune's average distance from our Sun is about 30.1 AU--its perihelion is 29.8 AU, while its aphelion is 30.4 AU. Dr. Alice Le Gall commented in the same JPL Press Release that "Before Cassini, we expected to find that Ligeia Mare would be mostly made up of ethane, which is produced in abundance in the atmosphere when sunlight breaks methane molecules apart. Instead, this sea is predominantly made of pure methane." Dr. Le Gall, a Cassini radar team associate, is of the French research laboratory LATMOS, in Paris, and lead author of the new study. The relatively light regions of the Moon are known as the highlands. The dark features, the lunar maria, are impact basins that were later filled with lava between 4.2 and 1.2 million years ago. These light and dark regions were created by rocks of different ages and compositions. This provides evidence for how the ancient crust may have crystallized from a global lunar ocean of magma. The impact craters have been preserved for billions of years, and they provide observers with an impact history for our Moon and other bodies that inhabit the inner Solar System.

Caroline Herschel was an astronomer in the late 1700s and early 1800s. She was known for her observations of nebulae, which at the time included comets, galaxies, what we now call nebulae, as they all appeared “fuzzy” in telescopic observations. She discovered her first comet in 1796,1 and went on to discover seven more, which was a huge accomplishment at the time. She was an honorary member of the Royal Astronomical Society and the Royal Irish Academy (women were not admitted as full members then), and was awarded the Gold Medal of Science by the King of Prussia. She also did much of her work in the shadow of her brother William. William Herschel is perhaps most famous for his discovery of Uranus, but this was really just a matter of chance. William had no reason to suspect there was a planet beyond Saturn, and was not specifically looking for planets at the time. His real interest was in deep sky objects, and this required careful observations with ever larger telescopes. Of course this type of work is hard to do alone, which is where Caroline comes in. Caroline began working with her brother as his housekeeper, but she had skill and interest as an astronomer, and eventually became her brother’s apprentice. This meant she did much of the skilled tedious work such as grinding and polishing mirrors for William’s telescopes, and doing much of the record work for their observations. The term “apprentice” doesn’t really match the work that Caroline did. When William was away on business, Caroline continued with their observations on her own. She was only 4 foot 3, and most of the observations they made were on a 20 foot long telescope that had to be aligned by hand. They also had a 40 foot telescope, that was particularly unwieldy and not entirely safe. On one evening after a snowfall, Caroline slipped and fell against a supporting hook, which gouged her above the knee. The doctor who treated her declared such an injury would put a soldier out of commission for weeks, but she was up and working again in days. After William’s death, Caroline continued her work as an astronomer. Toward the end of her life she compiled and catalogued all the discoveries she and her brother made. She presented the work to the Royal Astronomical Society. At a time when women were often seen merely as the supporters of the work of men, Caroline distinguished herself as a partner in her brother’s more famous work and as astronomer in her own right. Proving that astronomy is women’s work as well. Herschel, Caroline. “VI. Account of the discovery of a new comet. By Miss Caroline Herschel. In a letter to Sir Joseph Banks, Bart. KBPR S.” Philosophical Transactions of the Royal Society of London 86 (1796): 131-134. ↩︎

‘Hole in the ALMA sky’ is produced by hot cluster gas Do you see the large ‘hole’ in this ALMA image? It looks as if someone cut a circular hole in a blue veil, with a large cluster of galaxies right behind the hole. But appearances can be deceiving. In fact, the ‘blue veil’ originates behind the galaxy cluster. It’s the so-called cosmic background radiation –the faint remnant from the energy of the Big Bang. This background radiation is reaching us from 13.8 billion light-years. The galaxy cluster is much closer: less than 5 billion light-years. So, what’s going on? The effect that causes the ‘hole’ was first predicted almost 50 years ago by two Russian astronomers: Rashid Sunyaev and Yakov Zel’dovich. That’s why it’s called the Sunyaev-Zel’dovich effect. Because those names are so hard to pronounce, everyone just calls it the SZ effect. Here’s how it works. The cosmic background radiation is observed at millimeter and submillimeter wavelengths –precisely the wavelengths that ALMA can see. The photons of the background radiation (the individual particles of light) have very little energy. To observe them, ALMA uses ‘receivers’ that are sensitive to those low energy levels. So far, so good. But something funny happens when the radiation passes through a cluster of galaxies. In between the galaxies in the cluster is a lot of very hot gas. The photons of the cosmic background radiation interact with charged particles in the hot gas. As a result, they get an energy boost, as if they are kicked in the butt. So, when they leave the cluster again, on their way to Earth, they have a much higher energy then when they entered. Since ALMA is only observing at low energies, it cannot see these ‘kicked’ photons anymore. That’s why there appears a hole in the ALMA observations. In the image, the ALMA data (the ‘blue veil’) are combined with a Hubble Space Telescope photo of the cluster. The cluster neatly coincides with the ‘hole’, just as you would expect. Astronomers are excited about these new observations. It’s the first time that the SZ effect has been observed by ALMA. By studying the effect, it’s possible to learn more about the distribution and the properties of the hot gas in the cluster, even though ALMA cannot observe this gas directly. The galaxy cluster in the image is called RX J1347.5-1145. It consists of many hundreds of individual galaxies. The cluster is located at 4.8 billion light-years, in the constellation Virgo the Virgin. The Sunyav-Zel’dovich effect of this cluster had already been measured by other telescopes, but the ALMA observations are much more sensitive and show more detail. The ALMA measurements of the SZ-effect in this cluster were carried out by a very large team of Japanese astronomers, led by Tetsu Kitayama. To achieve a large field of view, Tetsu and his colleagues didn’t use the full array of 66 ALMA antennas, but the smaller Morita Array, which is part of ALMA. The Morita array (also known as the ALMA Compact Array) consists of just 12 antennas, each with a diameter of 7 meters (instead of 12 meters for the other 54 antennas). The results have been published in October 2016 in the Publications of the Astronomical Society of Japan.Check this in ALMA site

Double-Star Systems Can Be Dangerous for Exoplanets Alien planets born in widely separated two-star systems face a grave danger of being booted into interstellar space, a new study suggests. Exoplanets circling a star with a far-flung stellar companion — worlds that are part of “wide binary” systems — are susceptible to violent and dramatic orbital disruptions, including outright ejection, the study found. Such effects are generally limited to sprawling planetary systems with at least one distantly orbiting world, while more compact systems are relatively immune. This finding, which observational evidence supports, should help astronomers better understand the structure and evolution of alien solar systems across the galaxy, researchers said.

Dark matter might not be interactive after all European Week of Astronomy and Space Science press release RAS PR 18/19 (EWASS 15) 4 April 2018 Astronomers are back in the dark about what dark matter might be, after new observations showed the mysterious substance may not be interacting with forces other than gravity after all. Dr Andrew Robertson of Durham University will today (Friday 6 April) present the new results at the European Week of Astronomy and Space Science in Liverpool. Three years ago, a Durham-led international team of researchers thought they had made a breakthrough in ultimately identifying what dark matter is. Observations using the Hubble Space Telescope appeared to show that a galaxy in the Abell 3827 cluster – approximately 1.3 billion light years from Earth – had become separated from the dark matter surrounding it. Such an offset is predicted during collisions if dark matter interacts with forces other than gravity, potentially providing clues about what the substance might be. The chance orientation at which the Abell 3827 cluster is seen from Earth makes it possible to conduct highly sensitive measurements of its dark matter. However, the same group of astronomers now say that new data from more recent observations shows that dark matter in the Abell 3827 cluster has not separated from its galaxy after all. The measurement is consistent with dark matter feeling only the force of gravity. Lead author Dr Richard Massey, in the Centre for Extragalactic Astronomy, at Durham University, said: “The search for dark matter is frustrating, but that’s science. When data improves, the conclusions can change. “Meanwhile the hunt goes on for dark matter to reveal its nature. “So long as dark matter doesn’t interact with the Universe around it, we are having a hard time working out what it is.” The Universe is composed of approximately 27 per cent dark matter with the remainder largely consisting of the equally mysterious dark energy. Normal matter, such as planets and stars, contributes a relatively small five per cent of the Universe. There is believed to be about five times more dark matter than all the other particles understood by science, but nobody knows what it is. However, dark matter is an essential factor in how the Universe looks today, as without the constraining effect of its extra gravity, galaxies like our Milky Way would fling themselves apart as they spin. In this latest study, the researchers used the Atacama Large Millimetre Array (ALMA) in Chile, South America, to view the Abell 3827 cluster. ALMA picked up on the distorted infra-red light from an unrelated background galaxy, revealing the location of the otherwise invisible dark matter that remained unidentified in their previous study. Research co-author Professor Liliya Williams, of the University of Minnesota, said: “We got a higher resolution view of the distant galaxy using ALMA than from even the Hubble Space Telescope. “The true position of the dark matter became clearer than in our previous observations.” While the new results show dark matter staying with its galaxy, the researchers said it did not necessarily mean that dark matter does not interact. Dark matter might just interact very little, or this particular galaxy might be moving directly towards us, so we would not expect to see its dark matter displaced sideways, the team added. Several new theories of non-standard dark matter have been invented over the past two years and many have been simulated at Durham University using high-powered supercomputers. Robertson, who is a co-author of the work, and based at Durham University’s Institute for Computational Cosmology, added: "Different properties of dark matter do leave tell-tale signs. “We will keep looking for nature to have done the experiment we need, and for us to see it from the right angle. "One especially interesting test is that dark matter interactions make clumps of dark matter more spherical. That’s the next thing we’re going to look for." To measure the dark matter in hundreds of galaxy clusters and continue this investigation, Durham University has just finished helping to build the new SuperBIT telescope, which gets a clear view by rising above the Earth’s atmosphere under a giant helium balloon. The research was funded by the Royal Society and the Science and Technology Facilities Council in the UK and NASA. The findings will appear in a new paper in the journal Monthly Notices of the Royal Astronomical Society. Dr Robert Massey Royal Astronomical Society Mob: +44 (0)7802 877 699 Ms Anita Heward Royal Astronomical Society Mob: +44 (0)7756 034 243 Dr Morgan Hollis Royal Astronomical Society Mob: +44 (0)7802 877 700 Dr Helen Klus Royal Astronomical Society Dr Marieke Baan European Astronomical Society Mob: +31 6 14 32 26 27 Alternatively, please contact the Durham University Marketing and Communications Office Tel: +44 (0)191 334 6075 Dr Richard Massey Centre for Extragalactic Astronomy [Available for interview Wednesday 4 - Friday 6 April] Mob: +44 (0)7740 648 080 Dr Andrew Robertson Institute for Computational Cosmology [Available for interview Wednesday 4 – Friday 6 April] Mob: +44 (0)7954 364 755 Both Dr Massey and Dr Robertson will be attending the European Week of Astronomy and Space Science (EWASS) meeting in Liverpool (3-6 April) Professor Liliya Williams School of Physics and Astronomy University of Minnesota [Available for interview on Tuesday 3 – Thursday 5 April] Tel: +1 612-624-1084 Images and captions Hubble Space Telescope image of the four giant galaxies at the heart of cluster Abell 3827. An almost 3-hour exposure shows the view at wavelengths visible to the human eye, and the near infrared, as used in the original 2015 study. The distorted image of a more distant galaxy behind the cluster is faintly visible, wrapped around the four galaxies. Credit: NASA/ESA/Richard Massey (Durham University) A view of the four central galaxies at the heart of cluster Abell 3827, at a broader range of wavelengths, including Hubble Space Telescope imaging in the ultraviolet (shown as blue), and Atacama Large Millimetre Array imaging at very long (sub-mm) wavelengths (shown as red contour lines). At these wavelengths, the foreground cluster becomes nearly transparent, enabling the background galaxy to be more clearly seen. It is now easier to identify how that background galaxy has been distorted. Credit: NASA/ESA/ESO/Richard Massey (Durham University) A wide-field optical image of galaxy cluster Abell 3827. Credit: ESO The Superpressure Balloon-borne Imaging Telescope (SuperBIT) has just been built by an international team of scientists and engineers from Durham University, Princeton University, the University of Toronto, and NASA’s Jet Propulsion Laboratory. The telescope achieves an uninterrupted view of the night sky by rising above 99 per cent of the Earth’s atmosphere under a helium balloon the size of a football stadium. This novel route into space costs a tiny fraction of a rocket launch and is far quicker to design. Following two successful test flights, SuperBIT is scheduled to fly for three months from New Zealand in 2019. From there, it will measure the distribution of dark matter around 200 galaxy clusters, something that would have been impossible using existing technology like the Hubble Space Telescope. Photo credit: SuperBIT/Richard Massey. Videos (Mp4 format) and captions A supercomputer simulation of a collision between two galaxy clusters, similar to the real object known as the 'Bullet Cluster’, and showing the same effects tested for in Abell 3827. All galaxy clusters contain stars (orange), hydrogen gas (shown as red) and invisible dark matter (shown as blue). Individual stars, and individual galaxies are so far apart from each other that they whizz straight past each other. The diffuse gas slows down and becomes separated from the galaxies, due to the forces between ordinary particles that act as friction. If dark matter feels only the force of gravity, it should stay in the same place as the stars, but if it feels other forces, its trajectory through this giant particle collider would be changed. Credit: Andrew Robertson/Institute for Computational Cosmology/Durham University A simulation of the same collision if dark matter consisted of extremely strongly 'self-interacting’ particles that feel large forces in addition to gravity. The resulting distribution of dark matter and gas disagrees with what is observed in the real Universe - indeed, the interaction is so strong in this case that the dark matter stopped close to the point of impact. Since this is not seen in the real Universe, this enables us to rule out this particular model of dark matter. Credit: Andrew Robertson/Institute for Computational Cosmology/Durham University A simulation of the same collision if dark matter didn’t exist. The resulting distribution of stars and gas disagrees with what is observed in the real Universe, which provides compelling evidence that dark matter is present in the real Universe. Credit: Andrew Robertson/Institute for Computational Cosmology/Durham University Images and video are also available on request from the Durham University Marketing and Communications Office (details above) The new research will appear in “Dark matter dynamics in Abell 3827: new data consistent with standard Cold Dark Matter”, R. Massey et al., Monthly Notices of the Royal Astronomical Society, in press. It follows up the 2015 research paper, “The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827”, R. Massey et al., Monthly Notices of the Royal Astronomical Society, Volume 449, Issue 4, 1 June 2015, Pages 3393–3406. Notes for editors The European Week of Astronomy and Space Science (EWASS 2018) will take place at the Arena and Conference Centre (ACC) in Liverpool from 3 - 6 April 2018. Bringing together around 1500 astronomers and space scientists, the conference is the largest professional astronomy and space science event in the UK for a decade and will see leading researchers from around the world presenting their latest work. EWASS 2018 is a joint meeting of the European Astronomical Society and the Royal Astronomical Society. It incorporates the RAS National Astronomy Meeting (NAM), and includes the annual meeting of the UK Solar Physics (UKSP) group. The conference is principally sponsored by the Royal Astronomical Society (RAS), the Science and Technology Facilities Council (STFC) and Liverpool John Moores University (LJMU). About Durham University - A world top 100 university with a global reputation and performance in research and education (QS 2018 and THE World University Rankings 2018) https://www.dur.ac.uk/about/rankings - Ranked fourth in the UK in the Guardian University Guide 2018 and fifth in the 2018 Times and Sunday Times Good University Guide. - A member of the Russell Group of leading research-intensive UK universities. - Research at Durham shapes local, national and international agendas, and directly informs the teaching of our students. - Ranked the world top 40 globally for the employability of its students by blue-chip companies world-wide (QS World University Rankings 2017/18). - Highest rate of employment and further study in the UK for undergraduates completing their first degree (Higher Education Statistics Agency 2017/18). Liverpool John Moores University (LJMU) is one of the largest, most dynamic and forward-thinking universities in the UK, with a vibrant community of 25,000 students from over 100 countries world-wide, 2,500 staff and 250 degree courses. LJMU celebrated its 25th anniversary of becoming a university in 2017 and has launched a new five-year vision built around four key ‘pillars’ to deliver excellence in education; impactful research and scholarship; enhanced civic and global engagement; and an outstanding student experience. The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others. The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content. The European Astronomical Society (EAS) promotes and advances astronomy in Europe. As an independent body, the EAS is able to act on matters that need to be handled at a European level on behalf of the European astronomical community. In its endeavours the EAS collaborates with affiliated national astronomical societies and also with pan-European research organisations and networks. Founded in 1990, the EAS is a society of individual members. All astronomers may join the society, irrespective of their field of research, or their country of work or origin. In addition, corporations, publishers and non-profit organisations can become organizational members of the EAS. The EAS, together with one of its affiliated societies, organises the annual European Week of Astronomy & Space Science (formerly known as JENAM) to enhance its links with national communities, to broaden connections between individual members and to promote European networks. 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STFC also supports UK astronomy through the international European Southern Observatory. Follow STFC on Twitter STFC is part of UK Research and Innovation

In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis. In particular, it can refer to the gradual shift in the orientation of Earth's axis of rotation in a cycle of approximately 25,772 years. This is similar to the precession of a spinning-top, with the axis tracing out a pair of cones joined at their apices. The term "precession" typically refers only to this largest part of the motion; other changes in the alignment of Earth's axis--nutation and polar motion--are much smaller in magnitude. Earth's precession was historically called the precession of the equinoxes, because the equinoxes moved westward along the ecliptic relative to the fixed stars, opposite to the yearly motion of the Sun along the ecliptic. Historically, the discovery of the precession of the equinoxes is usually attributed in the West to the 2nd-century-BC astronomer Hipparchus. With improvements in the ability to calculate the gravitational force between planets during the first half of the nineteenth century, it was recognized that the ecliptic itself moved slightly, which was named planetary precession, as early as 1863, while the dominant component was named lunisolar precession. Their combination was named general precession, instead of precession of the equinoxes. Lunisolar precession is caused by the gravitational forces of the Moon and Sun on Earth's equatorial bulge, causing Earth's axis to move with respect to inertial space. Planetary precession (an advance) is due to the small angle between the gravitational force of the other planets on Earth and its orbital plane (the ecliptic), causing the plane of the ecliptic to shift slightly relative to inertial space. Lunisolar precession is about 500 times greater than planetary precession. In addition to the Moon and Sun, the other planets also cause a small movement of Earth's axis in inertial space, making the contrast in the terms lunisolar versus planetary misleading, so in 2006 the International Astronomical Union recommended that the dominant component be renamed the precession of the equator, and the minor component be renamed precession of the ecliptic, but their combination is still named general precession. Many references to the old terms exist in publications predating the change. "Precession" and "procession" are both terms that relate to motion. "Precession" is derived from the Latin praecedere ("to precede, to come before or earlier"), while "procession" is derived from the Latin procedere ("to march forward, to advance"). Generally the term "procession" is used to describe a group of objects moving forward. The stars viewed from Earth are seen to proceed from east to west daily, due to the Earth's diurnal motion, and yearly, due to the Earth's revolution around the Sun. At the same time the stars can be observed to anticipate slightly such motion, at the rate of approximately 50 arc seconds per year, a phenomenon known as the "precession of the equinoxes". In describing this motion astronomers generally have shortened the term to simply "precession". In describing the cause of the motion physicists have also used the term "precession", which has led to some confusion between the observable phenomenon and its cause, which matters because in astronomy, some precessions are real and others are apparent. This issue is further obfuscated by the fact that many astronomers are physicists or astrophysicists. The term "precession" used in astronomy generally describes the observable precession of the equinox (the stars moving retrograde across the sky), whereas the term "precession" as used in physics, generally describes a mechanical process. The precession of the Earth's axis has a number of observable effects. First, the positions of the south and north celestial poles appear to move in circles against the space-fixed backdrop of stars, completing one circuit in approximately 26,000 years. Thus, while today the star Polaris lies approximately at the north celestial pole, this will change over time, and other stars will become the "north star". In approximately 3200 years, the star Gamma Cephei in the Cepheus constellation will succeed Polaris for this position. The south celestial pole currently lacks a bright star to mark its position, but over time precession also will cause bright stars to become south stars. As the celestial poles shift, there is a corresponding gradual shift in the apparent orientation of the whole star field, as viewed from a particular position on Earth. Secondly, the position of the Earth in its orbit around the Sun at the solstices, equinoxes, or other time defined relative to the seasons, slowly changes. For example, suppose that the Earth's orbital position is marked at the summer solstice, when the Earth's axial tilt is pointing directly toward the Sun. One full orbit later, when the Sun has returned to the same apparent position relative to the background stars, the Earth's axial tilt is not now directly toward the Sun: because of the effects of precession, it is a little way "beyond" this. In other words, the solstice occurred a little earlier in the orbit. Thus, the tropical year, measuring the cycle of seasons (for example, the time from solstice to solstice, or equinox to equinox), is about 20 minutes shorter than the sidereal year, which is measured by the Sun's apparent position relative to the stars. After about 26 000 years the difference amounts to a full year, so the positions of the seasons relative to the orbit are "back where they started". (Other effects also slowly change the shape and orientation of the Earth's orbit, and these, in combination with precession, create various cycles of differing periods; see also Milankovitch cycles. The magnitude of the Earth's tilt, as opposed to merely its orientation, also changes slowly over time, but this effect is not attributed directly to precession.) For identical reasons, the apparent position of the Sun relative to the backdrop of the stars at some seasonally fixed time slowly regresses a full 360° through all twelve traditional constellations of the zodiac, at the rate of about 50.3 seconds of arc per year, or 1 degree every 71.6 years. At present, the rate of precession corresponds to a period of 25,772 years, but the rate itself varies somewhat with time (see Values below), so one cannot say that in exactly 25,772 years the earth's axis will be back to where it is now. The discovery of precession usually is attributed to Hipparchus (190-120 BC) of Rhodes or Nicaea, a Greek astronomer. According to Ptolemy's Almagest, Hipparchus measured the longitude of Spica and other bright stars. Comparing his measurements with data from his predecessors, Timocharis (320-260 BC) and Aristillus (~280 BC), he concluded that Spica had moved 2° relative to the autumnal equinox. He also compared the lengths of the tropical year (the time it takes the Sun to return to an equinox) and the sidereal year (the time it takes the Sun to return to a fixed star), and found a slight discrepancy. Hipparchus concluded that the equinoxes were moving ("precessing") through the zodiac, and that the rate of precession was not less than 1° in a century, in other words, completing a full cycle in no more than 36000 years. Virtually all of the writings of Hipparchus are lost, including his work on precession. They are mentioned by Ptolemy, who explains precession as the rotation of the celestial sphere around a motionless Earth. It is reasonable to presume that Hipparchus, similarly to Ptolemy, thought of precession in geocentric terms as a motion of the heavens, rather than of the Earth. The first astronomer known to have continued Hipparchus's work on precession is Ptolemy in the second century AD. Ptolemy measured the longitudes of Regulus, Spica, and other bright stars with a variation of Hipparchus's lunar method that did not require eclipses. Before sunset, he measured the longitudinal arc separating the Moon from the Sun. Then, after sunset, he measured the arc from the Moon to the star. He used Hipparchus's model to calculate the Sun's longitude, and made corrections for the Moon's motion and its parallax (Evans 1998, pp. 251-255). Ptolemy compared his own observations with those made by Hipparchus, Menelaus of Alexandria, Timocharis, and Agrippa. He found that between Hipparchus's time and his own (about 265 years), the stars had moved 2°40', or 1° in 100 years (36" per year; the rate accepted today is about 50" per year or 1° in 72 years). It is possible, however, that Ptolemy simply trusted Hipparchus' figure instead of making his own measurements. He also confirmed that precession affected all fixed stars, not just those near the ecliptic, and his cycle had the same period of 36,000 years as found by Hipparchus. Most ancient authors did not mention precession and, perhaps, did not know of it. For instance, Proclus rejected precession, while Theon of Alexandria, a commentator on Ptolemy in the fourth century, accepted Ptolemy's explanation. Theon also reports an alternate theory: Instead of proceeding through the entire sequence of the zodiac, the equinoxes "trepidated" back and forth over an arc of 8°. The theory of trepidation is presented by Theon as an alternative to precession. Various assertions have been made that other cultures discovered precession independently of Hipparchus. According to Al-Battani, the Chaldean astronomers had distinguished the tropical and sidereal year so that by approximately 330 BC, they would have been in a position to describe precession, if inaccurately, but such claims generally are regarded as unsupported. The archaeologist Susan Milbrath has speculated that the Mesoamerican Long Count calendar of "30,000 years involving the Pleiades...may have been an effort to calculate the precession of the equinox." This view is held by few other professional scholars of Mayan civilization. Similar claims have been made that precession was known in Ancient Egypt during the dynastic era, prior to the time of Hipparchus (Ptolemaic period). However, these claims remain controversial. Some buildings in the Karnak temple complex, for instance, allegedly were oriented toward the point on the horizon where certain stars rose or set at key times of the year. Nonetheless, they kept accurate calendars and if they recorded the date of the temple reconstructions it would be a fairly simple matter to plot the rough precession rate. The Dendera Zodiac, a star-map from the Hathor temple at Dendera from a late (Ptolemaic) age, allegedly records precession of the equinoxes (Tompkins 1971). In any case, if the ancient Egyptians knew of precession, their knowledge is not recorded as such in any of their surviving astronomical texts. Michael Rice wrote in his Egypt's Legacy, "Whether or not the ancients knew of the mechanics of the Precession before its definition by Hipparchos the Bithynian in the second century BC is uncertain, but as dedicated watchers of the night sky they could not fail to be aware of its effects." (p. 128) Rice believes that "the Precession is fundamental to an understanding of what powered the development of Egypt" (p. 10), to the extent that "in a sense Egypt as a nation-state and the king of Egypt as a living god are the products of the realisation by the Egyptians of the astronomical changes effected by the immense apparent movement of the heavenly bodies which the Precession implies." (p. 56). Rice says that "the evidence that the most refined astronomical observation was practised in Egypt in the third millennium BC (and probably even before that date) is clear from the precision with which the Pyramids at Giza are aligned to the cardinal points, a precision which could only have been achieved by their alignment with the stars. " (p. 31) The Egyptians also, says Rice, were "to alter the orientation of a temple when the star on whose position it had originally been set moved its position as a consequence of the Precession, something which seems to have happened several times during the New Kingdom." (p. 170) Before 1200, India had two theories of trepidation, one with a rate and another without a rate, and several related models of precession. Each had minor changes or corrections by various commentators. The dominant of the three was the trepidation described by the most respected Indian astronomical treatise, the Surya Siddhanta (3:9-12), composed c. 400 but revised during the next few centuries. It used a sidereal epoch, or ayanamsa, that is still used by all Indian calendars, varying over the ecliptic longitude of 19°11? to 23°51?, depending on the group consulted. This epoch causes the roughly 30 Indian calendar years to begin 23-28 days after the modern vernal equinox. The vernal equinox of the Surya Siddhanta librated 27° in both directions from the sidereal epoch. Thus the equinox moved 54° in one direction and then back 54° in the other direction. This cycle took 7200 years to complete at a rate of 54?/year. The equinox coincided with the epoch at the beginning of the Kaliyuga in -3101 and again 3600 years later in 499. The direction changed from prograde to retrograde midway between these years at -1301 when it reached its maximum deviation of 27°, and would have remained retrograde, the same direction as modern precession, for 3600 years until 2299.:29-30 Another trepidation was described by Var?hamihira (c. 550). His trepidation consisted of an arc of 46°40? in one direction and a return to the starting point. Half of this arc, 23°20?, was identified with the Sun's maximum declination on either side of the equator at the solstices. But no period was specified, thus no annual rate can be assertained.:27-28 Several authors have described precession to be near 200,000revolutions in a Kalpa of 4,320,000,000years, which would be a rate of = 60?/year. They probably deviated from an even 200,000revolutions to make the accumulated precession zero near 500. Visnucandra (c. 550-600) mentions 189,411revolutions in a Kalpa or 56.8?/year. Bhaskara I (c. 600-680) mentions 94,110revolutions in a Kalpa or 58.2?/year. Bh?skara II (c. 1150) mentions 199,699revolutions in a Kalpa or 59.9?/year.:32-33 In medieval Islamic astronomy, precession was known based on Ptolemy's Almagest, and by observations that refined the value. Al-Battani, in his Zij Al-Sabi', after mentioning Hipparchus calculating precession, and Ptolemy's value of 1 degree per 100 solar years, says that he measured precession and found it to be one degree per 66 solar years. Subsequently, Al-Sufi mentions the same values in his Book of Fixed Stars, that Ptolemy's value for precession is 1 degree per 100 solar years. He then quotes a different value from Zij Al Mumtahan, which was done during Al-Ma'mun's reign, as 1 degree for every 66 solar years. He also quotes the aforementioned Al-Battani's Zij Al-Sabi' as adjusting coordinates for stars by 11 degrees and 10 minutes of arc to account for the difference between Al-Battani's time and Ptolemy's. In the Middle Ages, Islamic and Latin Christian astronomers treated "trepidation" as a motion of the fixed stars to be added to precession. This theory is commonly attributed to the Arab astronomer Thabit ibn Qurra, but the attribution has been contested in modern times. Nicolaus Copernicus published a different account of trepidation in De revolutionibus orbium coelestium (1543). This work makes the first definite reference to precession as the result of a motion of the Earth's axis. Copernicus characterized precession as the third motion of the Earth. Over a century later precession was explained in Isaac Newton's Philosophiae Naturalis Principia Mathematica (1687), to be a consequence of gravitation (Evans 1998, p. 246). Newton's original precession equations did not work, however, and were revised considerably by Jean le Rond d'Alembert and subsequent scientists. Hipparchus gave an account of his discovery in On the Displacement of the Solsticial and Equinoctial Points (described in Almagest III.1 and VII.2). He measured the ecliptic longitude of the star Spica during lunar eclipses and found that it was about 6° west of the autumnal equinox. By comparing his own measurements with those of Timocharis of Alexandria (a contemporary of Euclid, who worked with Aristillus early in the 3rd century BC), he found that Spica's longitude had decreased by about 2° in the meantime (exact years are not mentioned in Almagest). Also in VII.2, Ptolemy gives more precise observations of two stars, including Spica and concludes that in each case a 2°:40' change occurred during 128 BC and AD 139 (hence, 1° per century or one full cycle in 36000 years, that is, the precessional period of Hipparchus as reported by Ptolemy ; cf. page 328 in Toomer's translation of Almagest, 1998 edition)). He also noticed this motion in other stars. He speculated that only the stars near the zodiac shifted over time. Ptolemy called this his "first hypothesis" (Almagest VII.1), but did not report any later hypothesis Hipparchus might have devised. Hipparchus apparently limited his speculations, because he had only a few older observations, which were not very reliable. Why did Hipparchus need a lunar eclipse to measure the position of a star? The equinoctial points are not marked in the sky, so he needed the Moon as a reference point. Hipparchus already had developed a way to calculate the longitude of the Sun at any moment. A lunar eclipse happens during Full moon, when the Moon is in opposition. At the midpoint of the eclipse, the Moon is precisely 180° from the Sun. Hipparchus is thought to have measured the longitudinal arc separating Spica from the Moon. To this value, he added the calculated longitude of the Sun, plus 180° for the longitude of the Moon. He did the same procedure with Timocharis' data (Evans 1998, p. 251). Observations such as these eclipses, incidentally, are the main source of data about when Hipparchus worked, since other biographical information about him is minimal. The lunar eclipses he observed, for instance, took place on 21 April 146 BC, and 21 March 135 BC (Toomer 1984, p. 135 n. 14). Hipparchus also studied precession in On the Length of the Year. Two kinds of year are relevant to understanding his work. The tropical year is the length of time that the Sun, as viewed from the Earth, takes to return to the same position along the ecliptic (its path among the stars on the celestial sphere). The sidereal year is the length of time that the Sun takes to return to the same position with respect to the stars of the celestial sphere. Precession causes the stars to change their longitude slightly each year, so the sidereal year is longer than the tropical year. Using observations of the equinoxes and solstices, Hipparchus found that the length of the tropical year was 365+1/4-1/300 days, or 365.24667 days (Evans 1998, p. 209). Comparing this with the length of the sidereal year, he calculated that the rate of precession was not less than 1° in a century. From this information, it is possible to calculate that his value for the sidereal year was 365+1/4+1/144 days (Toomer 1978, p. 218). By giving a minimum rate he may have been allowing for errors in observation. To approximate his tropical year Hipparchus created his own lunisolar calendar by modifying those of Meton and Callippus in On Intercalary Months and Days (now lost), as described by Ptolemy in the Almagest III.1 (Toomer 1984, p. 139). The Babylonian calendar used a cycle of 235 lunar months in 19 years since 499 BC (with only three exceptions before 380 BC), but it did not use a specified number of days. The Metonic cycle (432 BC) assigned 6,940 days to these 19 years producing an average year of 365+1/4+1/76 or 365.26316 days. The Callippic cycle (330 BC) dropped one day from four Metonic cycles (76 years) for an average year of 365+1/4 or 365.25 days. Hipparchus dropped one more day from four Callippic cycles (304 years), creating the Hipparchic cycle with an average year of 365+1/4-1/304 or 365.24671 days, which was close to his tropical year of 365+1/4-1/300 or 365.24667 days. We find Hipparchus's mathematical signatures in the Antikythera Mechanism, an ancient astronomical computer of the second century BC. The mechanism is based on a solar year, the Metonic Cycle, which is the period the Moon reappears in the same place in the sky with the same phase (full Moon appears at the same position in the sky approximately in 19 years), the Callipic cycle (which is four Metonic cycles and more accurate), the Saros cycle and the Exeligmos cycles (three Saros cycles for the accurate eclipse prediction). The study of the Antikythera Mechanism proves that the ancients have been using very accurate calendars based on all the aspects of solar and lunar motion in the sky. In fact, the Lunar Mechanism which is part of the Antikythera Mechanism depicts the motion of the Moon and its phase, for a given time, using a train of four gears with a pin and slot device which gives a variable lunar velocity that is very close to the second law of Kepler, i.e. it takes into account the fast motion of the Moon at perigee and slower motion at apogee. This discovery proves that Hipparchus mathematics were much more advanced than Ptolemy describes in his books, as it is evident that he developed a good approximation of Kepler?s second law. The Mithraic Mysteries, colloquially also known as Mithraism, was a 1st-4th century neo-platonic mystery cult of the Roman god Mithras. The near-total lack of written descriptions or scripture necessitates a reconstruction of beliefs and practices from the archaeological evidence, such as that found in Mithraic temples (in modern times called mithraea), which were real or artificial "caves" representing the cosmos. Until the 1970s most scholars followed Franz Cumont in identifying Mithras as a continuation of the Persian god Mithra. Cumont's continuity hypothesis, and his concomitant theory that the astrological component was a late and unimportant accretion, is no longer followed. Today, the cult and its beliefs are recognized as a product of (Greco-)Roman thought, with an astrological component even more heavily pronounced than the already very astrology-centric Roman beliefs generally were. The details, however, are debated. As far as axial precession is concerned, one scholar of Mithraism, David Ulansey, has interpreted Mithras as a personification of the force responsible for precession. He argues that the cult was a religious response to Hipparchus's discovery of precession, which--from the ancient geocentric perspective--amounted to the discovery that the entire cosmos (i.e., the outermost celestial sphere of the fixed stars) was moving in a previously unknown way. His analysis is based on the so-called "tauroctony": the image of Mithras killing a bull that was located in the central place in every Mithraic temple. In the standard tauroctony, Mithras and the bull are accompanied by a dog, a snake, a raven, and a scorpion. According to Ulansey, the tauroctony is a star chart. The bull is Taurus, a constellation of the zodiac. In the astrological age that preceded the time of Hipparchus, the vernal equinox had taken place when the Sun was in the constellation of Taurus, and during that previous epoch the constellations of Canis Minor (The Dog), Hydra (The Snake), Corvus (The Raven), and Scorpius (The Scorpion)--that is, the constellations that correspond to the animals depicted in the tauroctony--all lay on the celestial equator (the location of which is shifted by the precession) and thus had privileged positions in the sky during that epoch. Mithras himself represents the constellation Perseus, which is located directly above Taurus the Bull: the same location occupied by Mithras in the tauroctony image. Mithras' killing of the Bull, by this reasoning, represented the power possessed by this new god to shift the entire cosmic structure, turning the cosmic sphere so that the location of the spring equinox left the constellation of Taurus (a transition symbolized by the killing of the Bull), and the Dog, Snake, Raven, and Scorpion likewise lost their privileged positions on the celestial equator. The iconography also contains two torch-bearing twins (Cautes and Cautopates) framing the bull-slaying image--one holding a torch pointing up and the other a torch pointing down. These torch-bearers are sometimes depicted with one of them (torch up) holding or associated with a Bull and a tree with leaves, and the other (torch down) holding or associated with a Scorpion and a tree with fruit. Ulansey interprets these torch-bearers as representing the spring equinox (torch up, tree with leaves, Bull) and the autumn equinox (torch down, tree with fruit, Scorpion) in Taurus and Scorpius respectively, which is where the equinoxes were located during the preceding "Age of Taurus" symbolized in the tauroctony as a whole. Thus Ulansey concludes that Mithraic iconography was an "astronomical code" whose secret was the existence of a new cosmic divinity, unknown to those outside the cult, whose fundamental attribute was his ability to shift the structure of the entire cosmos and thereby to control the astrological forces believed at that time to determine human existence, thus giving him the power to grant his devotees success during life and salvation after death (i.e., a safe journey through the planetary spheres and a subsequent immortal existence in the realm of the stars). A consequence of the precession is a changing pole star. Currently Polaris is extremely well suited to mark the position of the north celestial pole, as Polaris is a moderately bright star with a visual magnitude of 2.1 (variable), and it is located about one degree from the pole, with no stars of similar brightness too close. The previous pole star was Kochab (Beta Ursae Minoris, ? UMi, ? Ursae Minoris), the brightest star in the bowl of the "Little Dipper", located 16 degrees from Polaris. It held that role from 1500 BC to AD 500 . It was not quite as accurate in its day as Polaris is today. Today, Kochab and its neighbor Pherkad are referred to as the "Guardians of the Pole" (meaning Polaris). On the other hand, Thuban in the constellation Draco, which was the pole star in 3000 BC, is much less conspicuous at magnitude 3.67 (one-fifth as bright as Polaris); today it is invisible in light-polluted urban skies. When Polaris becomes the north star again around 27,800, due to its proper motion it then will be farther away from the pole than it is now, while in 23,600 BC it came closer to the pole. It is more difficult to find the south celestial pole in the sky at this moment, as that area is a particularly bland portion of the sky, and the nominal south pole star is Sigma Octantis, which with magnitude 5.5 is barely visible to the naked eye even under ideal conditions. That will change from the 80th to the 90th centuries, however, when the south celestial pole travels through the False Cross. This situation also is seen on a star map. The orientation of the south pole is moving toward the Southern Cross constellation. For the last 2,000 years or so, the Southern Cross has pointed to the south celestial pole. As a consequence, the constellation is no longer visible from subtropical northern latitudes, as it was in the time of the ancient Greeks. The images at right attempt to explain the relation between the precession of the Earth's axis and the shift in the equinoxes. These images show the position of the Earth's axis on the celestial sphere, a fictitious sphere which places the stars according to their position as seen from Earth, regardless of their actual distance. The first image shows the celestial sphere from the outside, with the constellations in mirror image. The second image shows the perspective of a near-Earth position as seen through a very wide angle lens (from which the apparent distortion arises). The rotation axis of the Earth describes, over a period of 25,700 years, a small circle (blue) among the stars, centered on the ecliptic north pole (the blue E) and with an angular radius of about 23.4°, an angle known as the obliquity of the ecliptic. The direction of precession is opposite to the daily rotation of the Earth on its axis. The orange axis was the Earth's rotation axis 5,000 years ago, when it pointed to the star Thuban. The yellow axis, pointing to Polaris, marks the axis now. The equinoxes occur where the celestial equator intersects the ecliptic (red line), that is, where the Earth's axis is perpendicular to the line connecting the centers of the Sun and Earth. (Note that the term "equinox" here refers to a point on the celestial sphere so defined, rather than the moment in time when the Sun is overhead at the Equator, though the two meanings are related.) When the axis precesses from one orientation to another, the equatorial plane of the Earth (indicated by the circular grid around the equator) moves. The celestial equator is just the Earth's equator projected onto the celestial sphere, so it moves as the Earth's equatorial plane moves, and the intersection with the ecliptic moves with it. The positions of the poles and equator on Earth do not change, only the orientation of the Earth against the fixed stars. As seen from the orange grid, 5,000 years ago, the vernal equinox was close to the star Aldebaran of Taurus. Now, as seen from the yellow grid, it has shifted (indicated by the red arrow) to somewhere in the constellation of Pisces. Still pictures like these are only first approximations, as they do not take into account the variable speed of the precession, the variable obliquity of the ecliptic, the planetary precession (which is a slow rotation of the ecliptic plane itself, presently around an axis located on the plane, with longitude 174°.8764) and the proper motions of the stars. The precessional eras of each constellation, often known as Great Months, are approximately: |Constellation||Year entering||Year exiting| |Taurus||4500 BC||2000 BC| |Aries||2000 BC||100 BC| |Pisces||100 BC||AD 2700| Axial precession is similar to the precession of a spinning top. In both cases, the applied force is due to gravity. For a spinning top, this force tends to be almost parallel to the rotation axis initially and increases as the top slows down. For a gyroscope on a stand it can approach 90 degrees. For the Earth, however, the applied forces of the Sun and the Moon are closer to perpendicular to the axis of rotation. The Earth is not a perfect sphere but an oblate spheroid, with an equatorial diameter about 43 kilometers larger than its polar diameter. Because of the Earth's axial tilt, during most of the year the half of this bulge that is closest to the Sun is off-center, either to the north or to the south, and the far half is off-center on the opposite side. The gravitational pull on the closer half is stronger, since gravity decreases with the square of distance, so this creates a small torque on the Earth as the Sun pulls harder on one side of the Earth than the other. The axis of this torque is roughly perpendicular to the axis of the Earth's rotation so the axis of rotation precesses. If the Earth was a perfect sphere, there would be no precession. This average torque is perpendicular to the direction in which the rotation axis is tilted away from the ecliptic pole, so that it does not change the axial tilt itself. The magnitude of the torque from the Sun (or the Moon) varies with the angle between the Earth's spin axis direction and that of the gravitational attraction. It approaches zero when they are perpendicular. For example, this happens at the equinoxes in the case of the interaction with the Sun. This can be seen to be since the near and far points are aligned with the gravitational attraction, so there is no torque due to the difference in gravitational attraction. Although the above explanation involved the Sun, the same explanation holds true for any object moving around the Earth, along or close to the ecliptic, notably, the Moon. The combined action of the Sun and the Moon is called the lunisolar precession. In addition to the steady progressive motion (resulting in a full circle in about 25,700 years) the Sun and Moon also cause small periodic variations, due to their changing positions. These oscillations, in both precessional speed and axial tilt, are known as the nutation. The most important term has a period of 18.6 years and an amplitude of 9.2 arcseconds. In addition to lunisolar precession, the actions of the other planets of the Solar System cause the whole ecliptic to rotate slowly around an axis which has an ecliptic longitude of about 174° measured on the instantaneous ecliptic. This so-called planetary precession shift amounts to a rotation of the ecliptic plane of 0.47 seconds of arc per year (more than a hundred times smaller than lunisolar precession). The sum of the two precessions is known as the general precession. The tidal force on Earth due to a perturbing body (Sun, Moon or planet) is expressed by Newton's law of universal gravitation, whereby the gravitational force of the perturbing body on the side of Earth nearest is said to be greater than the gravitational force on the far side by an amount proportional to the difference in the cubes of the distances between the near and far sides. If the gravitational force of the perturbing body acting on the mass of the Earth as a point mass at the center of Earth (which provides the centripetal force causing the orbital motion) is subtracted from the gravitational force of the perturbing body everywhere on the surface of Earth, what remains may be regarded as the tidal force. This gives the paradoxical notion of a force acting away from the satellite but in reality it is simply a lesser force towards that body due to the gradient in the gravitational field. For precession, this tidal force can be grouped into two forces which only act on the equatorial bulge outside of a mean spherical radius. This couple can be decomposed into two pairs of components, one pair parallel to Earth's equatorial plane toward and away from the perturbing body which cancel each other out, and another pair parallel to Earth's rotational axis, both toward the ecliptic plane. The latter pair of forces creates the following torque vector on Earth's equatorial bulge: The three unit vectors of the torque at the center of the Earth (top to bottom) are x on a line within the ecliptic plane (the intersection of Earth's equatorial plane with the ecliptic plane) directed toward the vernal equinox, y on a line in the ecliptic plane directed toward the summer solstice (90° east of x), and z on a line directed toward the north pole of the ecliptic. The value of the three sinusoidal terms in the direction of x for the Sun is a sine squared waveform varying from zero at the equinoxes (0°, 180°) to 0.36495 at the solstices (90°, 270°). The value in the direction of y for the Sun is a sine wave varying from zero at the four equinoxes and solstices to ±0.19364 (slightly more than half of the sine squared peak) halfway between each equinox and solstice with peaks slightly skewed toward the equinoxes (43.37°(-), 136.63°(+), 223.37°(-), 316.63°(+)). Both solar waveforms have about the same peak-to-peak amplitude and the same period, half of a revolution or half of a year. The value in the direction of z is zero. The average torque of the sine wave in the direction of y is zero for the Sun or Moon, so this component of the torque does not affect precession. The average torque of the sine squared waveform in the direction of x for the Sun or Moon is: and 1/2 accounts for the average of the sine squared waveform, accounts for the average distance cubed of the Sun or Moon from Earth over the entire elliptical orbit, and (the angle between the equatorial plane and the ecliptic plane) is the maximum value of ? for the Sun and the average maximum value for the Moon over an entire 18.6 year cycle. whereas that due to the Moon is: where i is the angle between the plane of the Moon's orbit and the ecliptic plane. In these two equations, the Sun's parameters are within square brackets labeled S, the Moon's parameters are within square brackets labeled L, and the Earth's parameters are within square brackets labeled E. The term accounts for the inclination of the Moon's orbit relative to the ecliptic. The term (C-A)/C is Earth's dynamical ellipticity or flattening, which is adjusted to the observed precession because Earth's internal structure is not known with sufficient detail. If Earth were homogeneous the term would equal its third eccentricity squared, where a is the equatorial radius (6378137 m) and c is the polar radius (6356752 m), so . |GM = 1.3271244×1020 m3/s2||GM = 4.902799×1012 m3/s2||(C - A)/C = 0.003273763| |a = 1.4959802×1011 m||a = 3.833978×108 m||? = 7.292115×10-5 rad/s| |e = 0.016708634||e = 0.05554553||= 23.43928°| The solar equation is a good representation of precession due the Sun because Earth's orbit is close to an ellipse, being only slightly perturbed by the other planets. The lunar equation is not as good a representation of precession due to the Moon because the Moon's orbit is greatly distorted by the Sun and neither the radius nor the eccentricity is constant over the year. Simon Newcomb's calculation at the end of the 19th century for general precession (p) in longitude gave a value of 5,025.64 arcseconds per tropical century, and was the generally accepted value until artificial satellites delivered more accurate observations and electronic computers allowed more elaborate models to be calculated. Jay Henry Lieske developed an updated theory in 1976, where p equals 5,029.0966 arcseconds (or 1.3969713 degrees) per Julian century. Modern techniques such as VLBI and LLR allowed further refinements, and the International Astronomical Union adopted a new constant value in 2000, and new computation methods and polynomial expressions in 2003 and 2006; the accumulated precession is: in arcseconds, with T, the time in Julian centuries (that is, 36,525 days) since the epoch of 2000. The rate of precession is the derivative of that: The constant term of this speed (5,028.796195 arcseconds per century in above equation) corresponds to one full precession circle in 25,771.57534 years (one full circle of 360 degrees divided with 5,028.796195 arcseconds per century) although some other sources put the value at 25771.4 years, leaving a small uncertainty. The precession rate is not a constant, but is (at the moment) slowly increasing over time, as indicated by the linear (and higher order) terms in T. In any case it must be stressed that this formula is only valid over a limited time period. It is a polynomial expression centred on the J2000 datum, empirically fitted to observational data, not on a deterministic model of the solar system. It is clear that if T gets large enough (far in the future or far in the past), the T² term will dominate and p will go to very large values. In reality, more elaborate calculations on the numerical model of the Solar System show that the precessional constants have a period of about 41,000 years, the same as the obliquity of the ecliptic. Note that the constants mentioned here are the linear and all higher terms of the formula above, not the precession itself. That is, is an approximation of Theoretical models may calculate the constants (coefficients) corresponding to the higher powers of T, but since it is impossible for a (finite) polynomial to match a periodic function over all numbers, the difference in all such approximations will grow without bound as T increases. However, greater accuracy can be obtained over a limited time span by fitting a high enough order polynomial to observation data, rather than a necessarily imperfect dynamic numerical model. So for present flight trajectory calculations of artificial satellites and spacecraft, the polynomial method gives better accuracy. In that respect, the International Astronomical Union chose the best-developed available theory. For up to a few centuries in the past and the future, all formulas do not diverge very much. For up to a few thousand years in the past and the future, most agree to some accuracy. For eras farther out, discrepancies become too large - the exact rate and period of precession may not be computed using these polynomials even for a single whole precession period. The precession of Earth's axis is a very slow effect, but at the level of accuracy at which astronomers work, it does need to be taken into account on a daily basis. Note that although the precession and the tilt of Earth's axis (the obliquity of the ecliptic) are calculated from the same theory and thus, are related to each other, the two movements act independently of each other, moving in opposite directions. Precession exhibits a secular decrease due to tidal dissipation from 59"/a to 45"/a (a = annum = Julian year) during the 500 million year period centered on the present. After short-term fluctuations (tens of thousands of years) are averaged out, the long-term trend can be approximated by the following polynomials for negative and positive time from the present in "/a, where T is in billions of Julian years (Ga): Precession will be greater than p+ by the small amount of +0.135052"/a between and . The jump to this excess over p+ will occur in only beginning now because the secular decrease in precession is beginning to cross a resonance in Earth's orbit caused by the other planets. According to Ward, when, in about 1,500 million years, the distance of the Moon, which is continuously increasing from tidal effects, has increased from the current 60.3 to approximately 66.5 Earth radii, resonances from planetary effects will push precession to 49,000 years at first, and then, when the Moon reaches 68 Earth radii in about 2,000 million years, to 69,000 years. This will be associated with wild swings in the obliquity of the ecliptic as well. Ward, however, used the abnormally large modern value for tidal dissipation. Using the 620-million year average provided by tidal rhythmites of about half the modern value, these resonances will not be reached until about 3,000 and 4,000 million years, respectively. However, due to the gradually increasing luminosity of the Sun, the oceans of the Earth will have vaporized before that time (about 2,100 million years from now). The longitudes of the first point of Aries, according to the two schools therefore differ by 23°? (-) 19°11? ... [Upper limit was increased by 42? of accumulated precession 1950-2000.]

Some of the most ancient light has been detected, giving the stars their birthdate, helping characterize dark matter, and opening up a new field of astronomy. The Early Universe The oldest light we can see is the cosmic microwave background, the remnant hiss of the universe’s massive expansion following the Big Bang. After that, the universe had expanded and cooled enough to make atoms, mostly hydrogen. No large scale structures like stars formed for millions of years, so there was nothing giving off light–cosmologists, who rely on ancient light of all sorts to do their work, call this the Dark Ages. Little is known about this time. Even when it ended with the formation of the first stars, the Cosmic Dawn, remained a blurry mystery until today. In a paper published in the journal Nature today, Judd Bowman et al. report finding an elusive fingerprint of the first stars. When the first stars were born, the ultraviolet light that poured out into the universe was sometimes absorbed by the surrounding hydrogen gas. In theory, astrophysicists should be able to track this interaction and see a dip in light intensity at a known frequency. In practice, however, the universe is expanding so old light signals are stretched and cooled. If the exact date of Cosmic Dawn was known, it would be a simple matter of correcting for the stretch and picking out the blip–without knowing the time when the first stars were born, the search for this tiny perturbation becomes a daunting needle-in-a-haystack task. Seeing the Cosmic Sunrise Bowman and colleagues were undeterred, however. They built a small radio telescope in the Australian desert, and swept through likely frequencies to which the signal could have cooled. More than a year ago, they found a blip at 78 megahertz that seemed to fit, but Bowman and his colleagues was exceedingly careful. “We performed numerous hardware and processing tests to validate the detection,” the team writes modestly–they fiddled with all the parameters, reoriented the antenna, and performed various extra tests for more than a year. In the end, the results–at least in this one experiment–stand up to scientific scrutiny. Knowing the dip occurs at 78 megahertz allows Bowman and his team to reverse engineer the expansion of the universe and give a confident estimate of when the first stars were born: 180 million years after the Big Bang. Shedding Light on Dark Matter Like any great science experiment, this one answers some fundamental questions about the universe we live in while opening the doors to many others. For example, the team was surprised to find that the absorption signal was twice as strong as models predicted. This means that the hydrogen gas pervading the early universe was much colder than previously thought, so it could absorb more of the ultraviolet radiation from the early stars. Why is it so much colder? Another astrophysicist, Rennan Barkana, thinks this is due to its interaction with dark matter, the mysterious 85% of all matter that only interacts with the rest of the universe via gravity. In an accompanying paper also published in Nature, Barkana contends that interactions between dark matter and protons and neutrons (collectively called baryons) were likely the strongest during this early cold time. “Specifically, at cosmic dawn, the cosmic gas is at its coldest: it was hotter before owing to its remnant thermal energy from the Big Bang and afterwards owing to X-rays and other heating radiation from astrophysical objects,” writes Barkana. “Therefore, if baryon–dark matter scattering is strongest at low relative velocities, then its effect might be evident only at cosmic dawn.” WATCH: NSF’s Peter Kurczynski summarizes the extraordinary findings. Interaction with dark matter would make the hydrogen gas even colder, because it is giving up energy to the dark matter. This could explain the stronger absorption signal Bowman et al. detected. Barkana’s analysis of how the signal would be impacted by dark matter-hydrogen gas interaction provides insight into the very essence of what dark matter could be. “Our analysis indicates […] that the dark-matter particle is no heavier than several proton masses, well below the commonly predicted mass of weakly interacting massive particles.” Weakly interacting massive particles, or WIMPs, are the leading contender for explaining the structure of dark matter, so this finding might turn the whole field on its head. That is, if the original finding is verified. Other, similar experiments are already underway, hopeful to tease out the 78 megahertz dip using other instruments. If they do, another powerful tool will be added to the cosmologist’s toolbox, as big a deal as the birth of multi-messenger astronomy last year. WATCH: Miles goes underground in Ontario to visit SNOLAB, a dark matter research facility. Banner image credit: N.R. Fuller, NSF.

There is a large black hole at the center of the Milky Way Galaxy called "Sagittarius A". Scientists have been observing Sagittarius A for about 20 years and thought that they new its patterns. The suddenly, in May 2019, while they were observing from the Keck Observatory in Hawaii, Sagittarius A suddenly flared. It became about 75 times brighter than they had ever previously observed. They are still studying the event to try to determine what caused it. The best guesses so far is that it was caused by a disruption of the matter falling into the black hole either from a passing star or a gas cloud. The flare lasted about 2.5 hours. The team at the Keck observatory recorded a time lapse video of the event. This from Universe Today: Even though the black hole at the center of the Milky Way is a monster, it’s still rather quiet. Called Sagittarius A*, it’s about 4.6 million times more massive than our Sun. Usually, it’s a brooding behemoth. But scientists observing Sgr. A* with the Keck Telescope just watched as its brightness bloomed to over 75 times normal for a few hours. The flaring is not visible in optical light. It’s all happening in the near-infrared, the portion of the infrared spectrum closest to optical light. Astronomers have been watching Sgr. A* for 20 years, and though the black hole does have some variability in its output, this 75 times normal flaring event is like nothing astronomers have observed before. This peak was over twice as bright as the previous peak flux level.

On this day, 130 years ago, Edwin Hubble was born in Marshfield, Missouri. Hubble is thought to be one of the greatest astronomers of all time. From NASA.gov: Most astronomers of Hubble’s day thought that all of the universe — the planets, the stars seen with the naked eye and with powerful telescopes, and fuzzy objects called nebulae — was contained within the Milky Way galaxy. Our galaxy, it was thought, was synonymous with the universe. In 1923 Hubble trained the Hooker telescope on a hazy patch of sky called the Andromeda Nebula. He found that it contained stars just like the ones in our galaxy, only dimmer. One star he saw was a Cepheid variable, a type of star with a known, varying brightness that can be used to measure distances. From this Hubble deduced that the Andromeda Nebula was not a nearby star cluster but rather an entire other galaxy, now called the Andromeda galaxy. In the following years, he made similar discoveries with other nebulae. By the end of the 1920s, most astronomers were convinced that our Milky Way galaxy was but one of millions in the universe. This was a shift in thought as profound as understanding the world was round and that it revolved around the sun. Hubble then went one step further. By the end of that decade, he had discovered enough galaxies to compare to each other. He created a system for classifying galaxies into ellipticals, spirals and barred spirals — a system called the Hubble tuning fork diagram, used today in an evolved form. But the most astonishing discovery Hubble made resulted from his study of the spectra of 46 galaxies, and in particular of the Doppler velocities of those galaxies relative to our own Milky Way galaxy. What Hubble found was that the farther apart galaxies are from each other, the faster they move away from each other. Based on this observation, Hubble concluded that the universe expands uniformly. Several scientists had also posed this theory based on Einstein’s General Relativity, but Hubble’s data, published in 1929, helped convince the scientific community. In honor of this great physicist, you are going to do some physics! YAAYY!!! Try these

Astronomers have witnessed a rare event: the birth of massive stars 2.73 million light-years away in the Triangulum Galaxy (Messier 33). At the center of two giant colliding gas clouds are some 10 young stars with masses tens of times that of the Sun. Their discovery indicates that such cloud-cloud collisions are a main pathway to creating giant stars in the nearby universe, which could help answer the long-standing question of how big stars form. Bringing the universe to your door. We’re excited to announce Astronomy magazine’s new Space and Beyond subscription box – a quarterly adventure curated with an astronomy-themed collection in every box. Learn More >> High-mass stars — those at least eight times the mass of the Sun — are the celebrities of galaxies. Although they’re relatively rare, they produce most of a galaxy’s visible light. They also strongly influence the environment around them through the radiation they release during their lifetimes and the heavy elements they scatter upon their explosive deaths. Their formation, however, remains debated. New research submitted to the Publications of the Astronomical Society of Japan and published on the preprint site ArXiv uses the Atacama Large Millimeter/submillimeter Array to study two giant clouds in M33. The clouds are 190,000 and 240,000 times more massive than the Sun, respectively, and contain molecules such as molecular hydrogen and carbon dioxide. The two clouds collided at supersonic speeds around 500,000 years ago. (Here, “supersonic” means faster than the speed of sound in the clouds’ environment. In dense regions of space, the speed of sound can be a few miles per second or more; on Earth at sea level, the speed of sound is just over 1,100 feet [340 meters] per second). The researchers looked specifically for signatures of carbon monoxide, which can be easily seen in radio observations, to chart the denser filamentary structures in the clouds. They also looked for a specific signature of hydrogen that indicates the presence of massive stars. At the center of the collision, they found 10 objects that appear to be young, massive stars. That makes it highly likely that the collision caused changes in the clouds’ gas that made it collapse to form the stars. Massive stars, which are harder to form than smaller stars, aren’t seen everywhere low-mass star formation occurs. So, the question is: Why not? Astronomers think massive star formation must require some sort of additional triggering mechanism, such as cloud-cloud collisions, strong winds blown off active stars, expanding gas heated by other massive stars or shockwaves sent out by exploding supernovae. But until recently, there was scant observational evidence supporting cloud-cloud collisions. This study, however, now bolsters that option as a way to form massive stars. “We have a number of different ideas of how massive star formation is initiated,” says Harold Yorke, an astronomer at the NASA Ames Research Center in Mountain View, California. “We know that molecular clouds are turbulent, so you would suspect massive stars could form in those conditions.” “Recently, there has been a lot of observational, theoretical evidence of the cloud-to-cloud collision as the formation mechanism of massive stars,” says Toshikazu Onishi at the Osaka Prefecture University in Osaka, Japan, and co-author on the new study. “This paper provides the first observational evidence of [cloud-to-cloud collision] for massive star formation in the [Triangulum Galaxy].”

All LinksTelescopes and Observatories 1st High Energy Astrophysics Observatory (HEAO 1. GSFC. NASA) The first of NASA's three High Energy Astronomy Observatories, HEAO 1 was launched aboard an Atlas Centaur rocket on 12 August 1977 and operated until 9 January 1979. During that time, it scanned the X-ray sky almost three times over 0.2 keV - 10 MeV, provided nearly constant monitoring of X-ray sources near the ecliptic poles, as well as more detailed studies of a number of objects through pointed observations. 2nd High Energy Astrophysics Observatory (HEAO 2, renamed Einstein. GSFC. NASA) The second High Energy Astronomy Observatory (HEAO-B) was launched into an approximate 100-min low Earth orbit on 13 November 1978. Renamed the Einstein Observatory, it operated (with one significant interruption) until April 1981 and made over 5,000 targeted observations. A Broad-Band Imaging X-ray All-Sky Survey (ABRIXAS) ABRIXAS is a small satellite mission which was planned to observe the X-ray sky in the energy band 0.5-10 keV. The mission failed shortly after launch in Spring 1999. Active Magnetospheric Particle Tracer Explorers (AMPTE) Advanced Camera for Surveys (ACS) The Advanced Camera for Surveys (ACS) will be installed in the Hubble Space Telescope (HST) during a Space Shuttle mission scheduled in 2000. ACS will increase the discovery efficiency of the HST by a factor of ten. ACS will consist of three electronic cameras and a complement of filters and dispersers that detect light from the ultraviolet at 1200 angstroms to the near infrared at 10,000 angstroms. Advanced Fiber-Optic Echelle (AFOE) A Spectrograph for Precise Stellar Radial Velocity Measurements. Advanced Satellite for Cosmology and Astrophysics (ASCA ASTRO-D) ASCA (formerly named Astro-D) is Japan's fourth cosmic X-ray astronomy mission, and the second for which the United States is providing part of the scientific payload. The satellite was successfully launched February 20, 1993. Air Force Maui Optical Station (AMOS) Information about the Air Force Maui Optical Station (AMOS), located on Maui, Hawaii. This is a dual-use facility, supporting both US government agencies as well as the civilian community. Assets include visible and IR sensors, and a 3.67 meter telescope under construction. Anglo-Australian Observatory (AAO) The Anglo-Australian Observatory operates the Anglo-Australian and UK Schmidt Telescopes at Siding Spring, Australia, and a laboratory on the same campus as the ATNF in the Sydney Suburb of Epping. Antarctic Muon and Neutrino Detector Array (AMANDA) Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) AST/RO is a 1.7m diameter telescope for submillimeter-wave astronomy and aeronomy at Amundsen-Scott South Pole Station. Apache Point Observatory APO is privately owned and operated by the Astrophysical Research Consortium. Located near Sunspot, New Mexico, the observatory consists of a 3.5-meter telescope, the 2.5-meter Sloan Digital Sky Survey telescope, and two smaller telescopes. AREA31 Radio Observatory A31RO is a privately owned astronomical radio observatory operated by the Interstellar Electromagnetics Institute/L'institut Electromagnetiques Interstellaires under cooperative agreement with the AREA31 Research Facility. It is located near Shelburne, Ontario, Canada, about 1-1/2 hrs drive NW of Toronto. The Project TARGET microwave SETI program (since 1985), previously conducted at the Hay River Radio Observatory and also the Algonquin Radio Observatory is the primary initiative. Arecibo Observatory - National Astronomy and Ionosphere Center (NAIC) Aristarchos (The New Greek Telescope) The New Greek Telescope project of the AI-NOA for the 2.3m Ritchey-Chretien telescope, funded by the European Commission and the General Secretariat for Research and Technology of the Hellenic Ministry of Development. Array of Low Energy X-ray Imaging Sensors (ALEXIS) ALEXIS' X-ray telescopes feature curved mirrors whose multilayer coatings reflect and focus low-energy X-rays or extreme ultraviolet light the way optical telescopes focus visible light. The satellite and payloads were funded by the Department of Energy and built by Los Alamos National Laboratory in collaboration with Sandia National Laboratory and the University of California-Space Sciences Lab. The Launch was provided by the Air Force Space Test Program on a Pegasus Booster on April 25, 1993. The mission is entirely controlled from a small groundstation at LANL. Asiago Observatory (Padova) Association Sciences et Techniques Jeunesse - Secteur Astronomie (ANSTJ, France) Astro-2 (Astro-2. MSFC. NASA) Astro-2 is a high-tech observatory flying for 16 days in the payload bay of the Space Shuttle Endeavour during the STS-67 mission. The Astro-2 instruments allow astronomers to view stars, galaxies, planets and quasars in ultraviolet light, which is invisible to our eye Atacama Large Millimeter Array - ESO Web site (ALMA) The Atacama Large Millimeter Array (ALMA) is the new name for the merger of the major millimeter array projects into one global project: the European Large Southern Array (LSA), the U.S. Millimeter Array (MMA), and possibly the Japanese Large Millimeter and Submillimeter Array (LMSA). This will be the largest ground-based astronomy project of the next decade after VLT/VLTI, and, together with the Next Generation Space Telescope (NGST), one of the two major new facilities for world astronomy coming into operation by the end of the next decade. Atacama Large Millimeter Array - NRAO Web site (ALMA) The Atacama Large Millimeter Array (ALMA) is a millimeter wavelength telescope. The U.S. side of the project is run by the National Radio Astronomy Observatory (NRAO), operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation (NSF). The European side of the project is a collaboration between the European Southern Observatory (ESO), the Centre National de la Recherche Scientifique, the Max-Planck-Gesellschaft, the Netherlands Foundation for Research in Astronomy and Nederlandse Onderzoekschool Voor Astronomie, and the United Kingdom Particle Physics and Astronomy Research Council. ATNF - Australia Telescope Compact Array (ATCA, Narrabri) The Paul Wild Observatory, near Narrabri, is part of the Australia Telescope National Facility (ATNF), and operated by the CSIRO; the Officer-in-Charge is Dr Graham Nelson. The Narrabri site contains the Australia Telescope Compact Array, which consists of five antennas located along a 3-km railtrack, and a 6th antenna 3 km further to the west. ATNF - Australia Telescope National Facility (CSIRO) CSIRO's Australia Telescope National Facility (ATNF) is an organisation that supports and undertakes research in radio astronomy. It operates the Australia Telescope, the collective name for a set of radio telescopes in New South Wales. These telescopes are used, individually or together, to study objects in the Universe ranging from the remains of dead stars to entire galaxies. ATNF - Mopra Observatory (ATNF Mopra) The Mopra 22-m antenna is part of the Australia Telescope National Facility (ATNF), operated by the CSIRO. It is intended for use in conjunction with other AT antennas (the six 22-m dishes at Narrabri, and the 64-m Parkes dish) to form the Long Baseline Array. Like the Parkes antenna, it is also used for single-dish operation; mm-wavelength receivers are to be installed soon. ATNF - Parkes Observatory (ATNF Parkes) The CSIRO Australia Telescope National Facility operates a group of radio telescopes collectively known as the Australia Telescope. The ATNF Parkes Observatory consists of a 64m telescope which is used as an independent instrument, and networked with other Australian and international radio telescopes for VLBI. Automated Patrol Telescope (APT) The Automated Patrol Telescope (APT) is a wide-field CCD imaging telescope, which is operated by the University of New South Wales at Siding Spring Observatory, Australia. Links to Automated telescopes on the Internet. BeppoSAX Mission (SAX) The X-ray astronomy satellite BeppoSAX (Satellite per Astronomia X "Beppo" in honor of Giuseppe Occhialini) is a project of the Italian Space Agency (ASI) with participation of the Netherlands Agency for Aerospace Programs (NIVR). In the framework of past and future X-ray missions BeppoSAX stands out for its wide spectral coverage, ranging from 0.1 to over 200 keV. The sensitivity of the scientific payload allows the detailed study over the entire energy band of sources as weak as about 1/20 of 3C273. This opens new perspectives in the study of broad band X-ray spectra and variability of cosmic sources. Berkeley Illinois Maryland Association (BIMA - Hat Creek) BIMA is a consortium consisting of the The University of California at Berkeley, The University of Illinois at Urbana and The University of Maryland at College Park which operates and maintains a millimeter-wave radio interferometer at Hat Creek, California. Big Bear Solar Observatory (BBSO) This site contains daily images from our solar optical telescope at Big Bear, California. Fulldisk images for the current month. H-alpha, white light, and Ca-II K-line images are generally available for every observing day; Ca-II K-line fulldisk archive; H-alpha fulldisk archive; White light fulldisk archive; Current high-resolution region images; Programs to read FITS images on IBM PCs and Macintoshes. Big Ear Radio Observatory (Ohio State University) Big Ear is a Kraus-type radio telescope which covers an area larger than three football fields. The telescope is famous for discovering some of the most distant known objects in the universe, and the longest-running SETI (Search for ExtraTerrestrial Intelligence) project. Birmingham Solar Oscillations Network (BiSON) The current status of the Birmingham Solar Oscillations Network - a global network for helioseismology. Additionally some recent results and publications are available. [site under reconstruction] Broad Band X-ray Telescope (BBXRT. GSFC. NASA) The Broad Band X-ray Telescope (BBXRT) was flown on the space shuttle Columbia (STS-35) on 1990 December 2-December 11, as part of the ASTRO-1 payload. The flight of BBXRT marked the first opportunity for performing X-ray observations over a broad energy range (0.3-12 keV) with a moderate energy resolution (typically 90 eV and 150 eV at 1 and 6 keV, respectively). Broadcast from Carl Sagan Observatory (ASTRO-USON WebTV) Live broadcast of solar observation from Observatorio "Carl Sagan", Universidad de Sonora, Mexico, from Monday to Saturday, 15 to 22 hrs UTC, weather permit. Brown University - Observatories Bucknell University Observatory Byurakan Astrophysical Observatory (Armenia) Cagliari Astronomical Observatory (International Latitude Station) The Cagliari Astronomical Observatory was established as International Latitude Astronomical Station of Carloforte in 1899, a small town of the sardinian island of S. Pietro. It has been, for about 80 years, one of the five international stations devoted to study the Earth rotation and polar motion. Observations with the zenital telescope were carried out, except in the period of the second world's war. Starting from 1978, the headquarters were moved to Punta Sa Menta, a site 15 km far from Cagliari which has the same latitude of the Carloforte station. (Satellite Laser Ranging, Astrophysics, Planetary Dynamics, Time Laboratory, Data Processing). Calar Alto Observatory (Centro Astronomico Hispano-Aleman) The German-Spanish Astronomical Center at Calar Alto is located in the Sierra de Los Filabres in Southern Spain. It operates four telescopes with apertures from 1.2m to 3.5m as well as a Schmidt reflector. A 1.5m-telescope is operated under the control of the Observatory of Madrid. Caltech Submillimeter Observatory (CSO) The Caltech Submillimeter Observatory (CSO) is a cutting-edge facility for astronomical research and instrumentation development. It consists of a 10.4-meter diameter Leighton radio dish situated in a compact dome near the summit of Mauna Kea, Hawaii. Cambridge Optical Aperture Synthesis Telescope (COAST) Cambridge Ryle Telescope Canada France Hawaii Telescope (ftp) (CFHT) Canada France Hawaii Telescope (CFHT) CFHT is a joint facility of the National Research Council of Canada, the Centre National de la Recherche Scientifique of France, and the University of Hawaii. The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. There is a Mirror copy of the Web site at CDS . A CFHT page at CADC has information about the CFHT archive, CCDs, proposal template and manuals. Canadian Automatic Small Telescope for Orbital Research (CASTOR Satellite Tracking Project) The Canadian Automatic Small Telescopes for Orbital Research project, based at the Royal Military College of Canada, uses small optical telescopes to track medium to high earth orbit satellites such as Russian, Molniya satellites. Carlsberg Meridian Telescope (CMT) The Carlsberg Meridian Telescope (formerly the Carlsberg Automatic Meridian Circle) is located on La Palma and is dedicated to carrying out high-precision optical astrometry. Carnegie Institution Observatories (OCIW) Case Western Reserve University - Nassau Station Robotic Telescope (CWRU) Cassini Mission to Saturn (UltraViolet Imaging Spectrograph, UVIS) Saturn and Titan will be the destination for the Cassini mission, a project under joint development by NASA, the European Space Agency and the Italian Space Agency. The U.S. portion of the mission is managed for NASA by the Jet Propulsion Laboratory. Catania Astrophysical Observatory (OAC) Daily solar images (chromosphere and photosphere). Cecil and Ida Green Piñon Flat Observatory (PFO) Center for Astrophysical Research in Antarctica (CARA) Center for Extreme Ultraviolet Astrophysics (CEA / EUVE) The Center for Extreme Ultraviolet Astrophysics (CEA) opened in September, 1990. CEA represents the culmination of twenty years of research and student training in the field of EUV astronomy brought to focus by the launch of NASA's research mission, the University of California at Berkeley Extreme Ultraviolet Explorer (EUVE), on June 7, 1992. Centro de Investigaciones de Astronomia (CIDA) The National observatory CIDA (Merida, Venezuela) hosts the biggest telescopes of the earth equatorial belt: schmidt, reflector, refractor, astrograph. Observatorio nacional están ubicados los telescopios astronómicos más importantes de Venezuela y de la zona ecuatorial terrestre. CERN Hybrid Oscillation Research apparatUS (CHORUS) Cerro Tololo Interamerican Observatory (CTIO) Cerro Tololo Interamerican Observatory is a complex of astronomical telescopes and instruments located approximately 80 km to the East of La Serena, Chile at an altitude of 2200 Meters. CTIO is operated by the Association of Universities for Research in Astronomy Inc. (AURA), under a cooperative agreement with the National Science Foundation as part of the National Optical Astronomy Observatories . CfA 1.2 m Millimeter-Wave Telescope (CfA_mini) The 1.2 meter Millimeter-Wave Telescope at the Harvard- Smithsonian Center for Astrophysics and its twin instrument at CTIO in Chile have been studying the distribution and properties of molecular clouds in our Galaxy and its nearest neighbours for over 20 years. Chandra X-ray Observatory (AXAF) The Chandra X-ray Observatory is the U.S. follow-on to the Einstein Observatory. Chandra was formerly known as AXAF, the Advanced X-ray Astrophysics Facility, but renamed by NASA in December, 1998. The Chandra spacecraft carries a high resolution mirror, two imaging detectors, and two sets of transmission gratings. The Center for High Angular Resolution Astronomy (CHARA) Array will consist of five 1-m aperture telescopes (with an eventual goal of seven) in a Y-shaped array contained within a 400m diameter circle. This configuration will provide high resolution interferometry in the visible spectral region as well as the K spectral band (2.2 micron), with a limiting resolution of 0.2 milliarcsec in the visible. Cherenkov Array at Themis (CAT) Homepage of the CAT (Cherenkov Array at Themis) imager. This is an atmospheric Cherenkov imaging telescope for detection of high-energy gamma rays (>200 GeV), sited in the French Pyrenees. Chicago Air Shower Array The Chicago Air Shower Array (CASA) is a very large array of scintillation counters located in Utah, fifty miles southwest of Salt Lake City. CASA has been operating since 1992 in coincidence with a second array, the Michigan Anti (MIA), is made of 2500 square meters of buried muon detectors. CASA is the most sensitive experiment built to date in the study of gamma-ray and cosmic ray interactions at energies above 100 TeV (10^14 electron-Volts). Research topics on data from this experiment cover a wide variety of physics issues, including the search for gamma-rays from extragalactic sources (quasars and gamma-ray bursts), the study of diffuse gamma-ray emission from the Galactic plane, and a measurement of the cosmic ray composition in the poorly understood region from 100 to 100,000 TeV. Cincinnati Observatory Center The Cincinnati Observatory Center is the first and oldest observatory in the United States. It has been founded in 1842. It hosts a 12-inch Merz und Mahler refractor and a 16-inch Alvan Clark refractor, each with a beautifully restored tube, mount, and mechanical clock drive. Collaboration between Australia and Nippon for a Gamma Ray Observatory in the Outback (CANGAROO) The project uses two gamma ray telescopes at a dark site 15 km from Woomera, a small town 500 km north of Adelaide. Complejo Astronómico El Leoncito (CASLEO) The Complejo Astronómico El Leoncito is an astronomical facility operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the Universities of La Plata, Córdoba and San Juan. Its main telescope is a 2.15 meter reflector, equipped with direct CCD camera, spectrographs, a photopolarimeter and other instruments. It is located at 2552 meters above the sea level, in a high quality astronomical site in the mountains of Calingasta, 240 km away from the city of San Juan (Argentina). The use of this facility is open to the national and international astronomical community. Compton Gamma-Ray Observatory (CGRO. GSFC. NASA) The Compton Gamma Ray Observatory is the second of NASA's Great Observatories. Compton, at 17 tons, the heaviest astrophysical payload ever flown, was launched on April 5, 1991 aboard the space shuttle Atlantis. Compton has four instruments that cover an unprecedented six decades of the electromagnetic spectrum, from 30 keV to 30 GeV. Compton/GRO Observatory Science Support Center/Guest Observer (Facility) Query the Library Database; Archive Data Selector; Archive Data Selector Demonstrator; Trouble Report Generator; Access the GRONEWS Bulletin Board The Constellation X-ray Mission (formerly HTXS) is a Next Generation X-ray Observatory dedicated to observations at high spectral resolution, providing as much as a factor of 100 increase in sensitivity over currently planned high resolution X-ray spectroscopy missions. COROT - Asterosismology and Search for Exoplanets A space mission of the French Space Agency (CNES), with a launch planned in 2004. COROT stands for COnvection ROtation and planetary Transits. Cosmic Anisotropy Telescope (CAT) The CAT is a three-element interferometer for cosmic microwave background observations at 13 to 17 GHz. COsmic Background Explorer (COBE) Cracow - Solar radio emission in dm wavelength Continuous observations of solar radio emission in decimeter wavelength have been maintained in Cracow since 1957. Beginning from January 1995 we provide the reduced data on-line. The new instrument for solar radio observations is under construction. It is to start its operation in May, 1995. Curtis Schmidt Telescope The Curtis Schmidt telescope is a 0.61/.91 meter diameter Schmidt telescope located at the Cerro Tololo InterAmerican Observatory , about 500 km north of Santiago, Chile. This telescope was originally installed at the University of Michigan's Portage Lake Observatory in 1950, and moved to the much clearer skies of north central Chile in 1966. Two thirds of the time on this telescope is available to US and Chilean astronomers, with the remaining one third reserved for astronomers from the Dept. of Astronomy at the University of Michigan. Danish telescopes around the world Dark Matter Telescope (DMT) The Dark Matter Telescope is a proposed 8.4 meter, 3-degree-field, synoptic survey telescope. Darwin (Space IR Interferometry Mission) Darwin is a proposal for a European infrared interferometer in space. Its first aim is to detect Earth-like planets around nearby stars, and then to search for a signature of life, ozone in an atmosphere. It could also be used as a general-purpose infrared observatory. Darwin was proposed to the European Space Agency (ESA) for a Cornerstone Mission in its Horizon 2000 Plus plan. In October 1995, ESA decided to study such an infrared interferometer as an option for its Interferometer Cornerstone. The Darwin and Edison teams have combined to promote the selection by ESA of this option. The Darwin advocacy team members are also members of the International Working Group on Space Interferometry , a pressure group for this type of mission. Final selection on cost, science and technology grounds will be made around 2000, for a launch in the period 2009 - 2017. David Dunlap Observatory, University of Toronto (DDO) The David Dunlap Observatory is located in Richmond Hill, Canada. As part of the University of Toronto's Department of Astronomy it operates optical telescopes for research, the largest being a 1.88m telescope. DDO is also a centre for student training and public education. Deep Space Network - Goldstone Deep Space Station (DSN) The NASA Deep Space Network - or DSN - is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports some Earth-orbiting missions, including emergency support of the Shuttle Space Transportation System. Deep Undersea Muon and Neutrino Detection (DUMAND) Directory tree of information about the DUMAND project, designed to serve the needs of the experimenters, as well as to make information about DUMAND progress available to the broader scientific public. Deutsches Interferometer fuer Vielkanalphotometrie und Astrometrie (DIVA) DIVA is a small astronomy satellite, planned for launch in 2004. It is aimed to measure positions, proper motions and parallaxes, brightness and color of at least 30 million stars. This amount and the high precision is unreached so far by any predecessor mission. In a sense it is a pathfinder mission for the technology of upcoming cornerstone missions in the ESA Horizon 2000+ and the NASA Origins programmes like GAIA, DARWIN, LISA, SIM etc. Dominion Astrophysical Observatory (DAO) The DAO is operated by the National Research Council of Canada's Herzberg Institute of Astrophysics ( NRC-HIA) as a national centre for astronomical research within Canada, with emphasis on UV, optical and IR astronomy. The Canadian Astronomy Data Centre (CADC) is a group within the DAO which is responsible for the Canadian archive of data from the Hubble Space Telescope as well the archive of data from the Canada-France-Hawaii Telescope. DAO's Facility Manual is now online. Dutch Open Telescope (DOT) Innovative new optical solar telescope at the Roque de los Muchachos Observatory on La Palma (Canary Islands). The DOT provides extended sequences of solar images in various wavelengths with high angular resolution (0.2 arcsec). The Eddington mission was proposed in early 2000 to ESA in response to the ``Call for mission proposals for two flexi-missions''. The proposal was submitted by an international scientific team led by I.W. Roxburgh (Astronomy Unit, QMW, Univ. of London, UK), J. Christensen-Dalsgaard (University of Aarhus, Denmark) and F. Favata (ESA/ESTEC). The mission has two complementary scientific aims, to produce the data on stellar oscillations necessary for understanding the interior structure and evolution of stars, and to detect and characterize habitable planets around other stars. Effelsberg Radio Telescope (MPIfR) The Max-Planck-Institut für Radioastronomie (MPIfR) operates the world's largest movable radio telescope, a 100-m single-dish near Effelsberg, 40 km south of Bonn, Germany. Einstein Observatory (HEAO-2) The second of NASA's three High Energy Astrophysical Observatories, HEAO 2, renamed Einstein after launch, was the first fully imaging X-ray telescope put into space. The few arcsecond angular resolution, the field-of-view of tens of arcminutes, and a sensitivity several 100 times greater than any mission before it provided, for the first time, the capability to image extended objects, diffuse emission, and to detect faint sources. It was also the first X-ray NASA mission to have a Guest Observer program. Overall, it was a key mission in X-ray astronomy and its scientific outcome completely changed the view of the X-ray sky. ESA - Villafranca Satellite Tracking Station (ESA - VILSPA: IUE, ISO) General information on the ESA Satellite Tracking Station and on the projects supported at Villafranca: IUE, Marecs and ISO (in the near future). The service includes links to other ESA Establishments. Estación de Observación Solar-Observatorio (EOS/OCS) The Astronomy Area of CIF-US (Center for Research on Physics/Universidad de Sonora, Hermosillo Sonora, Mexico), operates EOS (Estacion de Observacion Solar/Solar Observational Station)and OCS (Observatorio "Carl Sagan"), the only two solar observatories in the country with an observational program of active regions at the continuum, and H-Alpha and Calcium lines, through a two-heliostat system and a 15 cm refractor telescope. Live broadcast of solar observations through ASTRO-USON WebTV with the new 14 cm Maksutov-H-Alpha telescope. European Northern Observatory (ENO) The Instituto de Astrofísica de Canarias (IAC) and its Observatories (the Observatorio de Teide, on Tenerife, and the Observatorio del Roque de los Muchachos, on La Palma) make up a Spanish research and observational centre, which, since 1979, has been open to the international scientific community and effectively constitute the European Northern Observatory (ENO). European Southern Observatory (ESO) ESO, the European Southern Observatory, is a multinational organisation of eight European member states. It operates astronomical observatories in Chile and has its headquarters in Munich, Germany. European VLBI Network (EVN) The European VLBI network (EVN) home page includes general information on the EVN, including contact adresses around the network, Call for Proposals, the EVN PC page, EVN and global VLBI scheduling, VLBINFO account, EVN experiment feedback facility, Network monitoring reports and other technical documents, the EVN Newsletter archive and a description of the type of science that can be investigated with the EVN array. European X-ray Observatory (EXOSAT at GSFC. NASA) The European Space Agency's X-ray Observatory, EXOSAT, was operational from May 1983 to April 1986. During that time, EXOSAT made 1780 observations of a wide variety of objects, including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies, and supernova remnants. The following resources are similar (same sort-key, different text): European X-ray Observatory (EXOSAT at ESTEC, ESA) The Exosat satellite was operational from May 1983 until April 1986 and in that time made 1780 observations in the X-ray band of most classes of astronomical object. The payload consisted of three instruments that produced spectra, images and light curves in various energy bands. EUSO - Extreme Universe Space Observatory (EUSO) The "Extreme Universe Space Observatory - EUSO" is the first Space mission devoted to the investigation of cosmic rays and neutrinos of extreme energy (E > 5 x 10e19 eV), using the Earth's atmosphere as a giant detector, the detection being performed by looking at the streak of fluorescence light produced when such a particle interacts with the Earth's atmosphere. EUSO is a mission of the European Space Agency ESA, and it is currently under "Phase A" study with a goal for a three year mission starting in 2009. EUSO will be accommodated, as an external payload of the Columbus module, on the ISS International Space Station. Exploration of Neighboring Planetary Systems (ExNPS) NASA's plan for the Exploration of Neighboring Planetary Systems (ExNPS) consists of a long term program of continuous scientific discovery and technological development leading ultimately to the detection and characterization of Earth-like planets around nearby stars. Far Ultraviolet Spectroscopic Explorer (FUSE) Information on the Far Ultraviolet Spectroscopic Explorer, a satellite astronomy project based at The Johns Hopkins University FAST Mission (NASA Small Explorer Program) The NASA Fast Auroral Snapshot Explorer (FAST) Satellite is designed to investigate the plasma physics of the auroral phenomena which occur around both poles of the earth. Fiber Linked Unit for Optical Recombination (FLUOR) One of the three recombination instruments of IOTA interferometer. Fibre Large Area Multi Element Spectrograph (FLAMES, ESO VLT) FLAMES is a Fibre Facility for the ESO VLT. It includes an high and intermediate resolution optical spectrograph (GIRAFFE), with its own fibre system. Five College Radio Astronomy Observatory (FCRAO) The FCRAO was founded in 1969 by the University of Massachusetts, together with Amherst College, Hampshire College, Mount Holyoke College and Smith College. The original low frequency telescope was superseded in 1976 by a 14-m diameter radome-enclosed antenna for use at high radio frequencies (mm wavelengths), built primarily to study the physics and chemistry of interstellar clouds, circumstellar envelopes, planetary atmospheres, and comets. FOcal Reducer/low dispersion Spectrograph (FORS, ESO VLT) The two FORS instruments are designed as all-dioptric focal reducers for the ESO Very Large Telescope. They are capable of doing : direct imaging , long slit grism spectroscopy , multi object grism spectroscopy , polarimetry (FORS1), medium dispersion echelle grism spectroscopy (FORS2), and all sensible combinations of these modes (e.g. imaging- or spectropolarimetry) in the wavelength range from 330nm to 1100nm. Francois-Xavier Bagnoud Observatory (OFXB) The François-Xavier Bagnoud Observatory, located above the village of St-Luc in the Swiss Alps, stands at an altitude of 2200 metres. It is intended not only for the experienced amateur wishing to produce work of a quasi-professional quality, but also for the use of schools and for simple visitors. curious. Equipped with numerous instruments (60 cm reflecting telescope with CCD camera, 20 cm refracting telescope, coelostat, 16 cm coronagraph) it may be used day or night. Fred Lawrence Whipple Gamma-Ray Telescopes (Tucson, Ariz) FUEGOS - Multi-Object Area Spectrograph (ESO VLT) The FUEGOS instrument stands for Fibre Unit for Extra-Galactic Optical Spectroscopy and will be capable of performing Multi-object spectroscopy and Area spectroscopy in the 370nm to 900nm wavelength range and with two resolving powers, 17000 and 7500. Full-sky Astrometric Mapping Explorer (FAME) FAME is an astrometric satellite designed to determine with unprecedented accuracy the positions, distances, and motions of 40 million stars within our galactic neighborhood. It is a collaborative effort between the U.S. Naval Observatory (USNO) and several other institutions. FAME will measure stellar positions to less than 50 microarcseconds. It is a NASA MIDEX mission scheduled for launch in 2004. FUSE (French site, IAP, Paris) [in French] Site of the French team contributing to Far Ultraviolet Spectroscopic Explorer (FUSE). FUSE est un satellite observatoire de la NASA dédié à la spectroscopie haute résolution dans le domaine ultraviolet. Ce programme est realisé en coopération avec l'Agence Spatiale Canadienne et le Centre National d'Etudes Spatiales ( CNES). Galactic Exoplanet Survey Telescope (GEST) Galaxy Evolution Explorer (GALEX) A Space Ultraviolet imaging and spectroscopic mission that will map the global history and probe the causes of star formation over the redshift range 0 < z < 2. Gamma-Ray Astronomy with COMPTEL (MPE Garching) Local project documentation and utilities as well as collaboration-wide information sources are maintained by the MPE COMPTEL people for: COMPTEL Data Reduction Group work: documents, scientific results and utilities used by the data analysts, the processing team and the scientists. COMPASS software system work : technical and management documents, used and maintained by the MPE software team. the local computing environment : documents on system configuration, maintained by the MPE/RZG software team. MPE - COMPTEL People Matters: the weekly activity list individual 'home pages' Gamma-ray Large Area Space Telescope (GLAST) The GLAST Mission is under study for flight in the first decade of the next century. GLAST is a next generation high-energy gamma-ray observatory designed for making observations of celestial gamma-ray sources in the energy band extending from 10 MeV to more than 100 GeV. Gemini - U.K. Support Group (UKGSG) The U.K. GEMINI Support Group based at Oxford University, England is aimed at supporting the U.K. astronomer community in the use of the GEMINI 8m Telescopes. This site is the main source of information on the telescopes themselves, their instrument compliment, applying for observing time, observing with the GEMINI telecopes and post-observing data reduction/analysis for U.K. researchers. Gemini 8m Telescopes (Gemini) The Gemini 8m Telescopes Project is an international project to build two infrared-optimized telescopes. One telescope will be located on Mauna Kea, Hawaii; the other will be on Cerro Pachon, Chile. Gemini Multiobject Spectrographs (GMOS) There will be one GMOS for each of the two GEMINI 8-m telescopes (UK mirror) which are due for completion in 1998 and 2000. They will provide a versatile low/medium resolution spectroscopic capability which will exploit the excellent image quality delivered by the telescopes at optical and near-infrared wavelengths. Giant Metrewave Radio telescope Observatory (GMRT) The Giant Metrewave Radio Telescope (GMRT) consists of 30 fully steerable parabolic dish antennas of 45 m diameter and is located in western India about 100 kms east of Bombay (Mumbai). It is in the shape of a `Y' covering an area equivalent to a 25 km. dia. circle. GMRT operates currently in the range 120 to 1450 MHz and is the largest synthesis radio telescope in the world at metre wavelengths. GMRT has been opened for world wide use since January 2002. Astro-C, renamed Ginga (Japanese for 'galaxy'), was launched from the Kagoshima Space Center on 5 February 1987. The primary instrument for observations was the Large Area Counter (LAC). Ginga was the third Japanese X-ray astronomy mission, following Hakucho and Tenma. Ginga reentered the Earth's atmosphere on 1 November 1991. Global Astrometric Interferometer for Astrophysics (GAIA) GAIA is a preliminary concept for a second space astrometry mission (after HIPPARCOS), recently recommended within the context of ESA's Horizon 2000 Plus long-term scientific programme. It is aimed at the broadest possible astrophysical exploitation of optical interferometry using a modest baseline length. Global Oscillation Network Group (GONG) Goddard High Resolution Spectrograph Investigation Definition Team (GHRS-IDT) The GHRS is one of four axial instruments on the Hubble Space Telescope and is designed to obtain UV spectra over a wide range of resolutions. This page was set up as a reference source for team members and other users of the instrument. Gran Telescopio CANARIAS (GTC) The Gran Telescopio CANARIAS (GTC), is a high performance segmented 10-meter telescope to be installed in one of the best sites of the Northern Hemisphere: the Roque de los Muchachos Observatory (La Palma, Canary Islands, Spain). First light is planed for 2002. The GTC project is a Spanish initiative, led by the IAC ( Instituto de Astrofísica de Canarias ) with the aim of becoming an international project. GRANTECAN has undertaken the construction of this telescope. Grand Interferometre a 2 Telescopes (GI2T REGAIN) Optical Interferometer, Plateau du Calern, Departement Fresnel, Observatoire de la Côte d'Azur, France. The National Radio Astronomy Observatory in Green Bank (West Virginia) is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Grove Creek Observatory, Australia (GCO) Grove Creek Observatory in NSW Australia, specializes in CCD imaging and research. Accomodation is available for visiting amateur astronomers. Guillermo Haro Observatory (Cananea, Mexico) Haleakala Observatories (Hawaii) Hard Labor Creek Observatory (HLCO) Hartebeesthoek Radio Astronomy Observatory (HartRAO) Hat Creek Radio Observatory (UMD) Herschel Space Observatory (FIRST) The `Herschel Space Observatory' - the mission formerly known as FIRST - will perform photometry and spectroscopy in the 60-670 µm range. High Energy Astrophysics Observatories (HEASARC. GSFC. NASA) Comprehensive list of satellites with high energy astrophysics instrumentation. Includes images from these missions. High Energy Solar Spectroscopic Imager (HESSI) Studying the Fundamental Aspects of Solar Flares. High Energy Transient Explorer (HETE-2) The High Energy Transient Explorer is a small scientific satellite designed to detect and localize gamma-ray bursts. High Energy X-ray Timing Experiment (HEXTE) The High Energy X-ray Timing Experiment is one of 3 common-user instruments on board the Rossi X-ray Timing Explorer (RXTE) which was launched on 1995 December 30. The HEXTE is sensitive to X-rays from 15 to 250 keV and is able to time-tag photons in this energy range to 8 microseconds. High Resolution Fly's Eye Cosmic Ray Detector (HiRes) The HiRes detector - an atmospheric fluorescence detector: HiRes currently consists of two sites on top of two mountains separated by 13km in western Utah. The following resources are similar (same sort-key, different text): High Resolution Fly's Eye Cosmic Ray Detector (HiRes) The HiRes detector - an atmospheric fluorescence detector: HiRes currently consists of two sites on top of two mountains separated by 13km in western Utah. High-Resolution Near-Infrared Camera (CONICA, ESO VLT) The high-resolution near-IR camera CONICA covers the infrared wavelength range from 1 µm to 5 µm. It is installed at the Nasmyth B focus of the VLT Unit Telescope 1 to operate in conjunction with the Nasmyth Adaptive Optics System (NAOS). CONICA is designed to exploit the adaptively corrected telescope image at wavelengths longwards of 2 µm. Speckle interferometry can be performed, primarily at the shorter wavelengths. Hilal, Islam, Astronomy, and Cyberspace (Crescent Moon Sighting) This website provides Monthly Crescent Moon Sighting information for many locations around the world. This provides the basis for a lunar calendar. Hobby Eberly Telescope (HET) The Hobby-Eberly telescope (HET) is a new 9 meter telescope, built at the University of Texas McDonald Observatory near Ft. Davis Texas as a result of an international collaboration between the University of Texas at Austin, The Pennsylvania State University and Stanford University in the United States and Ludwig-Maximilians-Universitaet Muenchen, and Goerg-August-Universitaet Goettingen. The HET has been tailored for spectroscopy, and in particular, fiber-coupled spectroscopy. Hopkins Ultraviolet Telescope (HUT) Astronomers at the Johns Hopkins University designed the Hopkins Ultraviolet Telescope (HUT) to explore the far- and extreme-ultraviolet portions of the electromagnetic spectrum. HUT has a 36-inch primary mirror which collects ultraviolet light for a prime-focus spectrograph. The spectrograph disperses light in the 825 to 1850 Angstrom wavelength range with a resolution of 3 Angstroms Hubble Space Telescope (HST - from CADC) Also, there is a page from ST-ECF . The following resources are similar (same sort-key, different text): Hubble Space Telescope The best images from the Hubble space telescope. IAC / Observatorio del Teide IAC / Observatorio Roque de los Muchachos Infra-Red Space Interferometer DARWIN (IRSI / DARWIN) The `InfraRed Space Interferometry Mission' DARWIN (IRSI or DARWIN) is a cornerstone mission in the ESA `Horizon 2000+' science plan. The goals for this space mission is for the first time to detect terrestial planets in orbit around other stars than our Sun. Infra-Red Telescope Facility (IRTF) The IRTF is a 3.0 meter telescope optimized for use in the infrared. It was first built to support the Voyager missions to Jupiter. It is now the National facility for infrared astronomy providing continued support to planetary and deep space applications. Also contains an Anonymous FTP site: Manuals, Forms, Instrument information, Software tools. Infrared and Optical Telescope Array (IOTA) Infrared Array Camera for the Space Infrared Telescope Facility (IRAC) The Space Infrared Telescope Facility (SIRTF) contains three focal plane instruments, one of which is the Infrared Array Camera (IRAC). IRAC is a four-channel camera that provides simultaneous 5.12 x 5.12 arcmin images at 3.6, 4.5, 5.8, and 8 microns. Infrared Space Observatory U.S. Support Center (ISO) U.S. science support center for observers using the Infrared Space Observatory (ISO), a fully approved and funded project of the European Space Agency (ESA). Infrared Space Observatory (ISO) The Infrared Space Observatory (ISO) is an ESA (European Space Agency) mission with the participation of ISAS (Japan) and NASA (USA). This WWW server is maintained at the ISO Data Centre, which is based at Villafranca, Madrid, and is part of the Astrophysics Division of the Space Science Department. Infrared Spectrometer And Array Camera (ISAAC, ESO VLT) ISAAC covers the wavelength range 1-5µm and is designed primarily for: 'wide' (2.5x2.5') field imaging and long slit low & medium resolution spectroscopy. Institut de Radio Astronomie Millimétrique (IRAM) IRAM is an international institute for research in millimeter astronomy, cofunded by the CNRS (Centre National de la Recherche Scientifique, France), the MPG (Max Planck Gesellschaft, Germany), and since September 1990 the IGN (Instituto Geografico Nacional, Spain). The three IRAM sites are: Grenoble, France : the IRAM headquarters, Laboratories (the SIS junction lab the backend group, the receiver group ; Plateau de Bure, France : the interferometer of four 15-m antennas ; Granada, Spain : the Granada laboratories, the 30-m telescope located on Pico Veleta. Institute of Astronomy, Bulgaria (IABG) Institute of Astronomy, Bulgaria (IABG) and National Astronomical Observatory "Rozhen". Instituto Argentino de Radioastronomia (IAR) Información sobre las características del Instituto Argentino de Radioastronomía, sus facilidades instrumentales, tareas de investigación y desarrollo en curso, personal científico y técnico y actividades de extensión. Instituto Nacional de Astrofísica, Óptica y Electrónica. Astrophysics Department (INAOE, Mexico) Information on the Large Millimeter Telescope an about the Cananea observatory Interferometry Center of Excellence (ICE, JPL) The Interferometry Center of Excellence (ICE), at JPL, has been established to ensure the development and maintenance of a leading edge capability in optical and near-infrared interferometric astrometry and imaging. International Gamma-Ray Astrophysics Laboratory (INTEGRAL. ESTEC. ESA) Technical status of Integral. The mission utilises the service module (bus) under development for the ESA XMM project. Integral will be launched in 2001. The mission is conceived as an observatory led by ESA with contributions from Russia and NASA International Interference Mitigation (for Radio Astronomy) This Web site is a meeting place for anyone interested in the technical problems of making radio astronomical measurements in the presence of other radio signals. Postings on this site are from scientists and engineers around the world on subjects such as suppression of RFI from electronic devices, measurement of the electromagnetic environment, and techniques for separating weak cosmic signals from other radiation in the radio spectrum. International Liquid Mirror Telescope Project (ILMT) International Ultraviolet Explorer (IUE) The International Ultraviolet Explorer (IUE) satellite was launched on the 26th of January 1978 by a Thor-Delta rocket from Cape Kennedy and transferred into a geosynchronous orbit over the Atlantic Ocean. Information on the project is available at: * IUEDAC GSFC, NASA * IUE Observatory Villafranca, ESA Iowa Robotic Observatory (IRTF) A Consortium consisting of faculty from the Regents Universities of the State of Iowa (University of Iowa, Iowa State University, and University of Northern Iowa) manages this fully robotic Observatory for undergraduate teaching and research in astronomy and related fields. The Iowa Robotic Observatory (IRO) consists of a fully computerized telescope and enclosure, a large format imaging CCD camera and photometric filters. The Winer Mobile Observatory is providing a site in southeastern Arizona to maintain and operate the telescope. Iowa Robotic Telescopes Facilities (IRTF) The University of Iowa Physics and Astronomy Department maintains these pages as a guide to our suite of robotic, autonomous tasking telescopes. In addition to using these instruments for teaching and faculty and student research, limited observing time is made available to anyone with an interest in Astronomy and a valid observing request. IPS Radio & Space Services (IPS) IPS is a unit of the Australian Government Department of Administrative Services and provides the Australian radio propagation and space environment services. Includes: Sydney Regional Warning Centre; Culgoora Solar Observatory; Learmonth Solar Observatory; Prediction Services; Consultancy Services Isaac Newton Group - La Palma (ING) The Issac Newton Group consists of three telescopes, the 4.2 metre William Herschel Telescope, the 2.5 metre Isaac Newton Telescope, and the 1 metre Jacobus Kapteyn Telescope. They are situated at the Observatorio del Roque de los Muchachos, on the island of La Palma in the Canary Islands, and are operated by the Royal Observatories of the UK. This resource contains documentation for many of the major instruments, details of how to apply for time, brief descriptions of the telescopes, details and status of the service programme, current telescope schedules, weather information for La Palma, and pointers to other institutions which share the site. The site is mirrored at http://www.ast.cam.ac.uk/ING/ for faster access to UK users. James Clerk Maxwell Telescope (JCMT) The 15-m JCMT is situated close to the summit of Mauna Kea, Hawaii, and is the largest submillmetre facility in the world. It is owned and operated by the UK, Canada and the Netherlands on behalf of astronomers worldwide. Its home page contains information about the site, the antenna and the instrumentation, as well as a description of the JCMT-CSO interferometer, and details of the various time allocation processes. Jicamarca Radio Observatory (Peru) Radar studies of the ionosphere and upper atmosphere. Jodrell Bank Observatory (University of Manchester) Jodrell Bank Observatory is part of the University of Manchester's Department of Physics and Astronomy. The Laboratories are home to the Lovell Telescope and the MERLIN & VLBI National Facility which is operated by the University on behalf of PPARC. Joint Astronomy Centre (Hilo, Hawaii) The Joint Astronomy Centre incorporates the 15m James Clerk Maxwell Telescope (JCMT) and the 3.8m United Kingdom Infrared Telescope (UKIRT) on the 4200m summit of Mauna Kea along with the Centre's Hawaii headquarters in Hilo. The facility is operated by the Royal Observatory, Edinburgh on behalf of the Science and Engineering Research Council of the United Kingdom, the Nederlandse Organisatie Voor Wetenschappelijk Onderzoek and the National Research Council of Canada. Joint Institute for VLBI in Europe / European VLBI Network (JIVE / EVN) The European VLBI Network (EVN) was formed in 1980 by a consortium of five of the major radio astronomy institutes in Europe (the European Consortium for VLBI). Since 1980, the EVN and the Consortium has grown to include 9 institutes with 12 telescopes in 8 western European countries as well as associated institutes with telescopes in Poland, Russia, Ukraine and China. Proposals for additional telescopes in Spain and Italy are under consideration, and furthermore, the EVN can be linked to the 7-element Jodrell Bank MERLIN interferometer in the UK and to the US Very Long Baseline Array (VLBA) to create a " global network" . In 1993 the Joint Institute for VLBI in Europe (JIVE) was created, with the Netherlands Foundation for Research in Astronomy (Dwingeloo) acting as the host institute. It will provide both scientific user support and a correlator facility. Very Long Baseline Interferometry (VLBI) achieves ultra-high angular resolution and is a multi-disciplinary technique e.g. imaging of extragalactic radio sources, geodesy and astrometry. Kanzelhoehe Solar Observatory The Kanzelhoehe Solar Observatory is operated by the Institute of Geophysics, Astrophysics and Meteorology (IGAM) of the University of Graz, Austria. It is located near Villach, close to the Italian and Slovenian border. Operated continuously and devoted also to Solar surveillance since its foundation in 1943 it houses a rich archive of observations. Keck Observatory (CalTech) Kiepenheuer-Institut für Sonnenphysik (KIS) The Kiepenheuer-Institut is a research institution of the German state of Baden-Wuerttemberg, dedicated to the study of the Sun. It is located in Freiburg, Germany, and operates solar observing facilities at the Observatorio del Teide, Tenerife, Spain. Kitt Peak National Observatory (KPNO) There is also an anonymous ftp Kitt Peak Observing Information (KPNO) Koelner Observatorium fuer SubMillimeter Astronomie (KOSMA) The 3-m KOSMA telescope at Gornergrat (Switzerland) is operated by the I. Physikalisches Institut (Cologne, Germany). It can be used for observations between 210 and 820 GHz. The Observing Station of the Uppsala Observatory. La Silla - ESO Facilities Lake Afton Public Observatory (Wichita State University) Large Angle and Spectrographic Coronagraph for SOHO (LASCO/SOHO) This instrument monitors the solar corona above the Sun's limb in a similar way as we perceive the corona during a solar eclipse. It produces images of the corona in the visible spectrum and with distance off the Sun's center ranging from 1.1 to 32 solar radii. Large Binocular Telescope (LBT) The Large Binocular Telescope (LBT) is a collaboration between Arizona (25%), Italy (25%, represented by the Arcetri Astrophysical Observatory in Florence), Research Corporation (12.5%), the Ohio State University (12.5%), and Germany (25%, represented by the LBT Beteiligungsgesellschaft). The goal of the LBT project is to construct and exploit a binocular telescope consisting of two 8.4-meter mirrors on a common mount. This telescope will be equivalent in light-gathering power to a single 11.8-meter instrument. Because of its binocular arrangement, the telescope will have a resolving power (ultimate image sharpness) corresponding to a 23-meter telescope. Large Millimeter and Submillimeter Array Project (LMSA) Large Millimeter Telescope / Gran Telescopio Milimétrico (LMT) The Large Millimeter Telescope is a bi-national project sponsored by both U.S. and Mexican governments and institutions to build the largest single-dish millimeter-wavelength radio telescope ontop of the mountain Cerro La Negra near Puebla in Mexico. The telescope is currently under construction with a rough completion date near 2003. Laser Guide Star Adaptive Optics (LLNL) The focus of the Laser Guide Star Adaptive Optics Program at Lawrence Livermore National Laboratory (LLNL) is the development of integrated adaptive optics (AO) and sodium-layer laser guide star (LGS) systems for use on large astronomical telescopes. Laser Interferometer Gravitational-Wave Observatory (LIGO) LECS Instrument on BeppoSAX (SAX, ESTEC, ESA) SAX is devoted to systematic, integrated and comprehensive studies of galactic and extragalactic X-ray sources in the energy band 0.1 - 200 keV; the observational goal to be addressed is to continue and expand upon previous spectral and timing observations of celestial sources in those areas for which the existing information is missing or inadequate and will remain uncovered in the foreseable future. Leonardo da VINCI - Interferometry (VINCI) VINCI is the VLT INnterferometer Commissionning Instrument, a collaboration of ESO, DESPA (Observatoire de Paris), MPE and OMP. It combines the light coming from two telescopes using single-mode fluoride glass optical fibers. Liquid Mirrors at Université Laval (LM) Liquid Mirror (LM) technology is being developed at Université Laval. A f/1.2, 2.5 meter diameter, mercury mirror is being extensively tested in our testing tower. We are also exploring the use of gallium eutectics as reflecting liquids. The design of novel optical correctors to increase the accessible field of view of liquid mirrors up to 45 degrees is also addressed. Live images from a remote controlled telescope. (L) This is the first remote controlled telescope by internet with live images and free photos with long exposure. Register for free with a personal password and enjoy the Italian Sky (-1 UT time). Liverpool John Moores University, Astrophysics Research Institute (ARI, Liverpool JMU) Details of the research and teaching interests of the group, as well as information on the Liverpool Telescope project - a fully-robotic 2m telescope to be situated at the Observatorio del Roque de los Muchachos, La Palma. As well as the Astrophysics degree-course with Liverpool University, we also have an innovative distance learning course. Loiano Telescopes - Bologna Loiano Telescopes (Bologna, Italy) Tools and informations for observers at the 152 cm Loiano Telescope of Bologna Astronomical Observatory. Tools include a web form for submitting proposals. Informations on road map, weather and accomodations are available. Low Energy Gamma-Ray Imager (LEGRI) LEGRI is a payload for the first mission of the Spanish MINISAT platform. The objective of LEGRI is to demonstrate the viability of HgI2 detectors for space astronomy, providing imaging and spectroscopical capabilities in the 10-100 keV range. Low Frequency Array (LOFAR) The Low Frequency Array (LOFAR) is a radio telescope that will operate at the lowest frequencies that are accessible from earth. The current plan is that LOFAR will work in the range from 10-240 MHz. The telescope is being developed by ASTRON, based in Dwingeloo (the Netherlands), the Naval Research Laboratory in Washington DC (USA) and MIT Haystack Observatory (USA). Magellan Mission to Venus NASA's Magellan spacecraft made a dramatic conclusion to its highly successful mission at Venus when it is commanded to plunge into the planet's dense atmosphere Tuesday, October 11, 1994. During its four years in orbit around Earth's sister planet, the spacecraft has radar-mapped 98 percent of the surface and collected high-resolution gravity data of Venus. The purpose of the crash landing is to gain data on the planet's atmosphere and on the performance of the spacecraft as it descends. Up-to-date status reports will be available from this WWW page, which also offers Venus images and other highlights from the mission. The Maidanak Foundation is dedicated to supporting the scientific teams currently running the Mt. Maidanak Observatory, and to provide funding for key scientific equipment. Mauna Kea Observatories Mauritius Radio Telescope (MRT) MRT is a southern sky survey telescope, which is making a complimentary survey to 6C (southern sky) and observing selected southern sky pulsars. See UK and original MRT pages. McDonald Observatory (University of Texas, Austin) McDonald Observatory is located 450 miles west of Austin, Texas, in the Davis Mountains. At present, there are three operating telescopes: 2.7-meter, 2.1-meter, and .76-meter reflectors. The Observatory is equipped with a wide range of state-of-the-art instrumentation for imaging and spectroscopy in the optical and infrared, and it boasts one of the first and most productive lunar ranging stations. MDM Observatory (MDM Observatory) MDM Observatory was founded by the University of Michigan, Dartmouth College, and the Massachusetts Institute of Technology. Current operating partners include Michigan, Dartmouth, MIT, Ohio State University, and Columbia University. The Observatory is located on the southwest ridge of the Kitt Peak National Observatory near Tucson, AZ. It operates two telescopes: the 2.4-m Hiltner telescope and the 1.3-m McGraw-Hill telescope. Mees Solar Observatory (MSO, Hawaii) Metsahovi Radio Research Station The Metsähovi Radio Research Station, a separate research institute of the Helsinki University of Technology since May 1988, operates a 14 m diameter radome enclosed radio telescope at Metsähovi, 40 km west of Helsinki, Finland. The Cassegrain telescope system can be used at frequencies 10 - 230 GHz (wavelengths 3 cm - 1.8 mm). Michelle: A mid-infrared spectrometer and imager for the UKIRT and Gemini telescopes Michigan State's Telescope Initative Outreach efforts to merge astronomy research and non-science education. Microvariability and Oscillations of Stars (MOST - First Canadian Space Telescope) MOST is a suitcase-sized (65x65x30cm, 60kg) microsatellite designed to probe other stars and extrasolar planets by measuring tiny light variations undetectable from Earth. The following resources are similar (same sort-key, different text): Microvariability and Oscillations of Stars (MOST) MOST is Canada's first space science microsatellite and its first optical space telescope project, aiming for launch in late 2001. MOST is designed to measure (as its acronym implies) Microvariability & Oscillations of STars in broadband light with a precision of a few micromagnitudes over timescales from minutes to days. The resulting eigenfrequency data will be used primarily for stellar seismology, to probe the structure and ages of Sun-like stars, magnetic stars, Wolf-Rayet stars and halo subdwarfs. The subdwarfs are expected to yield age estimates which would place a meaningful lower limit on the age of the Universe. MOST should also be capable of confirming the presence of giant extrasolar planets identified in Doppler surveys. Microwave Anisotropy Probe (MAP) NASA has selected MAP has one of the next MIDEX missions. It will map the microwave background fluctuations over the whole sky and provide insights into the formation of galaxies and the basic parameters of cosmology. Mid-InfraRed Large Imager (MIRLIN) MIRLIN is a 128 x 128 pixel, 7 - 25 micrometer infrared astronomical camera built at JPL by a team led by Dr. Michael Ressler and used on the Palomar 5 meter (200 inch) telescope, the NASA Infrared Telescope Facility 3 meter telescope, and the Keck II 10 meter telescope. Midcourse Space Experiment (MSX) The MSX observatory is a Ballistic Missile Defense Organization project which offers major benefits for both the defense and civilian sectors. It was launched on a Delta II vehicle on April 24, 1996, into a 900 km, polar, near-Sun synchronous orbit. The spacecraft featured an advanced multispectral image capability to gather data on test targets and space background phenomena. The infrared sensors operated at 11 to 12 degrees Kelvin by employing a solid hydrogen cryostat. The IR instruments span the range 4.2 - 26 microns. The focal plane array consists of five bands and the radiometer beam-size is more than 25 times smaller than IRAS. As a result, much greater spatial resolution than anything currently available has been obtained. The cryogen phase of the mission ended on 26 February 1997. During the ten month cryogen phase of the mission over 200 Giga Bytes of data on Celestial Backgrounds were obtained. See the MSX Celestial Backgrounds Team Home Page for additional details. Millstone Hill Observatory (MHO, Haystack) The Millstone Hill Observatory, located in Westford Massachusetts, is a broad-based atmospheric sciences research facility owned and operated by the Massachusetts Institute of Technology. The Atmospheric Sciences Group, which staffs and manages the observatory, is a part of M.I.T's Haystack Observatory, a basic research organization whose focus is radio wave and radar science, instrumentation and techniques. The following resources may be of interest. EISCAT is a particularly good source of data and useful information. See, for example, incoherent scatter radar and magnetosphere Millstone Hill Observatory: Information, data, etc., including real-time radar status and data when the radar is operating. EISCAT: European Incoherent Scatter Association. NCAR: National Center for Atmospheric Research. NSF: National Science Foundation Gopher server. NASA: National Aeronautics and Space Administration. NGDC: National Geophysical Data Center. Mississippi State University - Howell Observatory Molonglo Observatory Synthesis Telescope (MOST) The MOST consists of two cylindrical paraboloids, 778m x 12m, separated by 15m and aligned East-West. A line feed system of 7744 circular dipoles collects the signal and feeds 176 preamplifiers and 88 IF amplifiers. The telescope is steered by mechanical rotation of the cylindrical paraboloids about their long axis, and by phasing the feed elements along the arms. The resulting `alt-alt' system can follow a field for +/- 6 hours (necessary for a complete synthesis with an East-West array) only if the field is south of declination -30 degrees. For fields near this limit the signal-to-noise ratio is considerably lower for the first and last hour or so due to the lower gain of the system at large `meridian distance' angles. MOnitoring X-ray Experiment (MOXE) The MOnitoring X-ray Experiment (MOXE) is an X-ray all-sky monitor to be launched on the Russian Spectrum-X-Gamma satellite. It will monitor several hundred X-ray sources on a daily basis, and will be the first instrument to monitor the complete X-ray sky simultaneously. MOXE is built by Los Alamos Nat Lab, Goddard Space Flight Center and Space Research Institute (Moscow). MONOPTEC's Fixed Shutter Dome (FSD) MONOPTEC licenses the Fixed Shutter Dome, an enabling technology in observatory enclosures and satellite laser ranging systems. Four FSD's now reside in Tokyo, Japan, as part of the Keystone Project. Monterey Institute for Research in Astronomy (MIRA) The Monterey Institute for Research in Astronomy is a non-profit astronomical observatory, founded in 1972 and dedicated to research and education in astronomy. Mount Evans Meyer-Womble Observatory (Denver Univ.) Mt.Evans Meyer-Womble Observatory, elev. 4,303 meters, in the Colorado Rockies. Dual 0.7 meter R-C telescopes, optical and mid-infrared instrumentation. Summer access. Collaborations invited. Mount Graham International Observatory (MGIO) The Mt. Graham International Observatory is located on Mt. Graham near Safford , Arizona. Two telescopes are now in operation, the Vatican Observatory/Arizona 1.8m Lennon telescope(VATT) and the 10m diameter Heinrich Hertz Submillimeter Telescope (SMT), a joint project of Arizona and the Max-Planck-Institut für Radioastronomie, Germany. Mount Laguna Observatory Mount Pleasant Radio Observatory (Tasmania) Mount Stromlo and Siding Spring Observatories - Observing facilities (MSSSO) The Australian National University runs the following telescopes: 2.3m at Siding Springs ; 74in at Mount Stromlo ; 50in at Mount Stromlo ; 40in at Siding Springs ; 24in at Siding Springs. Mount Suhora Observatory (Cracow Pedagogical University) The Mt.Suhora Observatory is a part of Astronomy Department at the Pedagogical University in Cracow, Poland. It is located in Gorce mountain, near Koninki village, 60 km south-east of Cracow. The scientific staff of 9 people works on photometry of variable stars. Mount Wilson Observatory The mountain is host to several ongoing observing projects using the onsite facilities. The observatory has two primary nighttime telescopes: the 60-inch telescope, built in 1908 is home to the HK Project and the Atmospheric Compensation Experiment; and the 100-inch (Hooker) telescope, built in 1917, which is available to the scientific community. Two solar observatories, the 60-foot tower telescope (operated by USC), and the 150-foot tower telescope (operated by UCLA) maintain long-term exploration of the magnetic activity behavior of the Sun. There are also two interferometers onsite: the Infrared Spatial Interferometer (ISI, operated by U.C. Berkeley), and the NRL Optical Interferometer. The Telescopes in Education (TIE) Project operates a 24" telescope, as well as the Snow Solar Telescope (built in 1904). Finally, a fully-robotic 32-inch Automatic Photoeletric Telescope (APT) is operated by Tennessee State University. Multi-Element Radio Linked Interferometer Network (MERLIN - Jodrell Bank) Multiband Imaging Photometer for SIRTF (MIPS) The Multiband Imaging Photometer for SIRTF (MIPS) is a far-infrared photometer, scheduled for launch into a solar orbit in December, 2001. It is one of three instruments that will fly on SIRTF. Multiple Mirror Telescope Observatory (1) (MMTO) Multiple Mirror Telescope Observatory (2) (MMTO) Muriwai Beach Observatory NZ The Nançay Radio Observatory is a scientific department (the Unite Scientifique de Nançay) of the Paris Observatory, and it is also associated to the CNRS (the French National Scientific Research Council). Nasmyth Adaptive Optics System (NAOS, ESO VLT) Nation River Observatory National Astronomical Observatory of Spain (OAN) OAN is a 200 year old institution devoted to research in astronomy that operates several observatories. The Yebes Observatory is the site of a mm-wave 14m telescope devoted to spectroscopy and VLBI. A 1.5m optical telescope is located at the Calar Alto Observatory. The OAN is also the Spanish partner of IRAM, which runs a 30m mm-wave telescope and a 5x15m mm-wave interferometer. National Centre for Radio Astrophysics (NCRA) National Centre for Radio Astrophysics is the leading centre in India for reseach in radio astronomy. It operates the Giant Metrewave Radio Telescope(GMRT), one of the most powerful radio telescopes in the world for radio astronomy at metre wavelengths. National Laboratory for Astrophysics (LNA, Brazil) LNA is an Institute of the National Council for Scientific and Technological Development (CNPq). At present, LNA supports 3 telescopes: the 1.6-m Ritchey-Chretien and coudé, the 0.6-m Cassegrain and the 0.6-m telescope of the University of São Paulo. National Schools' Observatory (NSO) The National Schools' Observatory is a major web-based resource that allows UK schools to use world-class astronomical telescopes sited all around the world. Using the resources and software developed by the Observatory, students can prepare and carry out their own astronomical research and share in the excitement of discovery. National Solar Observatory / Sacramento Peak, Sunspot, NM (NSO/SP) National Solar Observatory (NSO) Synoptic Solar Magnetograms National Undergraduate Research Observatory (NURO) The National Undergraduate Research Observatory (NURO) at Lowell Observatory and Northern Arizona University is a 0.8m telescope located on Anderson Mesa south of Flagstaff, Arizona. NURO is a consortium of Universities and small colleges to provide a research grade telescope for undergraduate research and education. Near-Earth Asteroid Tracking (NEAT) NEAT is an autonomous celestial observatory located at the USAF/Ground-based Electro-Optical Deep Space Surveillance (GEODSS) site on Haleakala, Maui, Hawaii. It is designed to complete a comprehensive search of the sky for near-Earth asteroids and comets. Neutrino Oscillation MAgnetic Detector (NOMAD) Nomad (Neutrino Oscillation MAgnetic Detector) is CERN experiment WA96. The experiment searches for the oscillation nu_mu -> nu_tau in the CERN wide-band neutrino beam. It aims at detecting tau-neutrino charged-current interactions by observing the production of the tau lepton through its various decay modes by means of kinematical criteria. New Radio Telescope Technologies Laboratory (NRTT Lab) NRRT Lab. of JSEC "Astronomy" in St.Petersburg, Russia. Current research: Antenna testing and research, development of new antenna technologies for radio telescopes including multielement feed arrays, MMIC focal receiver arrays, active phased arrays for radio telescopes. Development, investigation and introduction of new observation modes at RATAN-600 radio telescope. Next Generation Space Telescope listservs (NGST Listservs) This URL takes you to a WWW page where you can subscribe to a number of listservs devoted to the Next Generation Space Telescope project. You may subscribe to any of them. Posting is restricted. Right now, these are used as ways to inform the community about progress in the project. The web site contains links for feedback to the project team members. Next Generation Space Telescope (NGST) The Next Generation Space Telescope (NGST) is a critical component of NASA's Origins Program. It will be a telescope of aperture greater than 4m, radiatively cooled to 30 - 60 deg.K, permitting extremely deep exposures at near infrared wavelengths with a 10 year life. A key requirement is to break the HST cost paradigm through the use of new technology and management methods. This site is designed to serve as the starting point for finding online NGST Study documentation. There is also a public home page at NASA, and a European site at ST-ECF. NFO's Automatic Radio Linked Telescope Observatory associated with Western New Mexico University in Silver City, NM (USA). NICMOS UofA (NICMOS) The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is a second-generation instrument to be installed on the Hubble Space Telescope (HST) during the February 13, 1997 on-orbit servicing mission. NICMOS will provide infrared imaging and spectroscopic observations of astronomical targets between 0.8-2.5 microns. Nobeyama Radio Observatory, NAOJ (NRO) Information regarding the 45-m Telescope, the Millimeter Array(NMA), the Large Millimeter and Submillimeter Array (LMSA) project, and much more. Nordic Optical Telescope (NOT, La Palma) Noto VLBI Station Oak Ridge Observatory Observatoire de Haute-Provence (OHP) The Observatoire de Haute-Provence (OHP) is an optical observatory in southeast France offering small and medium-sized observing facilities to astronomers in France, Europe and abroad. Includes information about instruments and user manuals. Observatoire du Mont Megantic (OMM) The Centre de recherche Observatoire du mont Mégantic (OMM) is an inter-university collaborative organisation which brings together researchers from Université de Montréal, Université Laval, with axis centred on the télescope du mont Mégantic (TMM). The Centre unites most of the professional researchers working in astronomy and astrophysics in Québec. Observatoire du Mont Mégantic (OMM) Observatoire Midi-Pyrenees (OMP) The Observatoire Midi-Pyrénées (OMP) is an Observatoire des Sciences de l'Univers placed under the administrative supervison of both the Institute des Sciences de l'Univers (INSU) of the French National Center for Scientific Research (CNRS) and the Ministry of Research, Technology and Education. It has laboratories located on the Rangueuil campus of Université Paul Sabatier in Toulouse (UPS), in Bagnères, Lannemezan and on the summit of Pic du Midi de Bigorre. Observatorio Astronomico da Serra da Piedade (OAP, Mainas Gerais, Brazil) The Serra da Piedade observatory belongs to the Federal University of Minas Gerais state, Brazil. It is opened to the general public every first Saturday of each month for observations. Tutorials and workshops are also part of the program, presented by astronomers and undergraduate students of the university. The observatory is equipped with one Zeiss 0.6 meter reflector and one Zeiss 15cm Coudè refractor. The observatory is located 50km east of Belo Horizonte-MG, Brazil. Observatorio Astronómico Nacional The Observatorio Astronómico Nacional (OAN) operates 3 telescopes (2.1m, 1.5m, and 0.84m) up in the mountains of the Sierra San Pedro Martir of Baja California. The observatory offices and workshops are located in Ensenada, B.C. overlooking the Pacific ocean. OAN is a part of the Instituto de Astronomía of the Universidad Nacional Autónoma de México. Observatorio Nacional, Brazil (Rio de Janeiro) Observatorium Hoher List (Bonn) The Wide Field Imager for the VST at Paranal. Onsala Space Observatory (OSO) OSO is the Swedish National Facility for Radio Astronomy. Optical Correctors for Liquid Mirror Telescopes One of the often cited limitations of liquid mirror telescopes pertains to the small region of sky which they can observe. Because the aberrations of a parabola increase rapidly with field angle, classical corrector designs cannot yield subarcsecond images for angles significantly greater than one degree. To access larger fields, innovative corrector designs must be explored. In these pages we discuss the Optical Design and Testing of a family of two-mirror correctors to compensate the aberrations of a fixed parabolic mirror observing at a large angle from the zenith. Orbiting Very Long Baseline Interferometry (OVLBI) Owens Valley Radio Observatory (OVRO) Palomar Observatory (CalTech) Palomar Testbed Interferometer (PTI) Public Observatory located in Deleware, Ohio, USA. Offers public programs almost every weekend. Owned and operated by the Ohio Wesleyan University. Perugia University Astronomical Observatory Articles, data, researches, and new developments at Perugia University Astronomical Observatory. Pine Mountain Observatory (University of Oregon) Planck is the third Medium-Sized Mission (M3) of ESA's Horizon 2000 Scientific Programme. It is designed to image the anisotropies of the Cosmic Background Radiation Field over the whole sky, with unprecedented sensitivity and angular resolution. Planck will provide a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure. Planck was formerly called COBRAS/SAMBA. After the mission was selected and approved, it was renamed in honor of the German scientist Max Planck (1858-1947), Nobel Prize for Physics in 1918. Pushchino Radioastronomy Observatory (PRAO) (PRAO) Pushchino Radioastronomy Observatory of Astro Space Center of P.N.Lebedev Physical Institute (PRAO ASC LPI). Radio Ice Cherenkov Experiment (RICE) A prototype ultra-high energy neutrino detector/obervatory located at the South Pole. RICE consists of an array of radio antennas buried deep in the ice which detect coherent Cherenkov emission from electromagnetic cascades produced as a by product of ultra-high energy neutrino interactions. RadioAstron is a project led by the Astro Space Center of the Lebedev Physical Institute in Moscow, Russia, that will put a 10-meter radio telescope into a high elliptical orbit in order to make VLBI observations in conjunction with radio telescopes on the ground. It is part of the Spectrum series of spacecraft, also including Spectrum X-Gamma and Spectrum-UV. Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) RHESSI's primary mission is to explore the basic physics of particle acceleration and explosive energy release in solar flares. RHESSI is a NASA Small Explorer. RHESSI was launched on February 5, 2002. Robotic Lunar Observatory (ROLO) The Robotic Lunar Observatory (ROLO) is dedicated to studying one of the remaining unknowns of the Moon: what is its precise brightness? ROLO is currently part of the NASA Earth Observing Spacecraft Mission. The concept of the project is that the Moon will be observed repeatedly, and data gathered, so that we can predict the brightness of the Moon to better than two percent. Then, spacecraft orbiting the Earth can look at the Moon as part of a calibration sequence to get an absolute brightness reference. Robotic Optical Transient Search Experiment (ROTSE) ROTSE is an experimental program to search for astrophysical optical transients on time scales of a fraction of a second to a few hours. This is an area of astronomical science that has been relatively unexplored until now. The primary incentive for this research is to find the optical counterparts of gamma-ray bursts (GRBs). Two sets of instruments are now under construction: ROTSE-I, a 4-fold camera array using telephoto lenses to cover a 16 degree by 16 degree field of view and ROTSE-II, a pair of 0.45 meter aperture telescopes to cover a 2 degree by 2 degree field of view. The expected sensitivities of these two systems is expected to be m_v ~ 15 and 18 respectively. ROentgen SATellite (ROSAT at GSFC. NASA) ROSAT, the ROentgen SATellite, is an X-ray observatory developed through a cooperative program between the Germany, the United States, and the United Kingdom. The satellite was designed and is operated by Germany, and was launched by the United States on June 1, 1990. ROSAT Guest Observer Facility (ROSAT) The ROSAT Science Data Center (RSDC) is responsible for execution of the guest investigator program, including such activities as providing assistance in the preparation of proposals, the receiving, processing, and distributing ROSAT pointed data, and providing facilities for the scientific analysis of these data. Roentgen Satellite (X-ray satellite) operated by the Max-Planck-Institut für Extraterrestrische Physik (MPE), Garching, Germany. Rossi X-Ray Timing Explorer Project (RXTE) The Rossi X-ray Timing Explorer is designed to facilitate the study of time variability in the emission of X-ray sources with moderate spectral resolution. Royal Observatory, Edinburgh (ROE) This site offers information about the extensive activities of the Royal Observatory, Edinburgh, a PPARC establishment responsible for building common-user IR and sub-mm instrumentation and managing telescope sites and data archive resources, as well as the UK Schmidt Telescope and the SuperCOSMOS measuring machine. The ROE site also has links to, or acts as the home page for: * Institute for Astronomy, University of Edinburgh; * latest research e-prints; * the Crawford library; * the ROE Visitor Centre; * the UKIRT data archive; * Public Understanding of Science; * ROE Photolabs; * Teacher Research Inititive and much more information besides. RXTE Guest Observer Facility (GFSC) Santiago de Compostela - Astronomical Observatory Ramón María Aller (AO RMA) SAtellite for Measurement of cosmological Background Anisotropies (SAMBA) SAMBA will use bolometers to survey the sky in the 0.3-6mm wavelength range. The project has been selected by ESA for a merging with the COBRAS proposal, which gives the COBRAS/SAMBA mission, now named PLANCK. Schaller Observatory (Amateur High Speed Stellar Photometry) Schaller Observatory is dedicated to high speed stellar photometry and optical SETI. The site describes the observatory, computer controlled telescope. photomultiplier tube detector, amplifiers, filters, data acquisition and FFT analysis. Schmidt telescope at Observatoire de la Cote d'Azur The Telescope is located at the "Observatoire de Calern", above the city of Grasse. Equipped with a 2K CCD camera, it is mainly used for the OCA-DLR Asteroid Survey program. It is also used for geostationnaary Space Debris detection and GRB optical counterparts follow ups. Small Explorers (SMEX) NASA's Small Explorer (SMEX) program provides frequent flight opportunities for highly focused and relatively inexpensive science missions. Soft X-Ray Telescope onboard Yohkoh Satellite, ISAS, Japan (description at LMSAL, USA) Yohkoh (" Sunbeam" in Japanese) is a satellite of the Japanese Institute of Space and Astronautical Science (ISAS) dedicated to high-energy observations of the Sun, specifically of flares and other coronal disturbances Solar and Heliospheric Observatory (SOHO) The SOHO project is being carried out by the European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA) as a cooperative effort between the two agencies in the framework of the Solar Terrestrial Science Program (STSP). SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by Matra, and instruments were provided by European and American scientists. Solar Extreme-ultraviolet Rocket Telescope and Spectrograph (SERTS) The Solar Extreme-ultraviolet Rocket Telescope and Spectrograph (SERTS) instrument obtains spatially resolved spectra and spectroheliograms over a wide range of extreme ultraviolet (EUV) wavelengths characteristic of temperatures between 5x10^4-3x10^7K, providing information about the Sun's corona and upper transition region. Wavelength coverage is 170-450A with spectral resolution near 10000, spatial resolution as good as 5arcsec, and relative photometric accuracy within +/- 20% over most of its range. This page contains links to information about the instrument, a solar EUV line list between 170 and 450 A from the SERTS-89 flight, and a list of SERTS-related publications. Soon to be added is information about upcoming launches. Also included are links to other WWW servers relevant to solar astronomers. Solar Group of RATAN-600 The group provides Solar Radio Monitoring on RATAN-600. Observations are performed with a high spatial, one - dimensional resolution scan near UT 9-00 at 30-40 wavelengths in the range from 1.67 cm up to 32 cm with left (LCP) and right (RCP) circular polarization. There are FITS and GIF data archives available from May 1997. Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) STACEE is a new experiment for detecting gamma-rays with energies from 20 to 300 GeV, corresponding to the last unopened window in the electromagnetic spectrum. STACEE will use a the heliostats available at a large solar power facility to collect Cherenkov light that results from gamma-ray air showers. STACEE is currently under development and should be operational sometime in 1997 or 1998. South African Astronomical Observatory (SAAO) The South African Astronomical Observatory (SAAO) is the National Facility for optical/infrared astronomy in South Africa. Its prime function is to further fundamental research in astronomy and astrophysics at a national and international level through the provision and use of a world-class astronomical facility. Southeastern Association for Research in Astronomy (SARA) The SARA telescope consortium operates the 0.9 meter SARA optical telescope on Kitt Peak. Southern African Large Telescope (SALT) SALT, a 9-m class southern hemisphere twin of the Hobby-Eberly Telescope (HET) in Texas, to be built at the Sutherland observing station of the South African Astronomical Observatory. Southern Columbia Millimeter Telescope (1.2 Meter) Space Infrared Telescope Facility (SIRTF) - Infrared Spectrograph (IRS) The Infrared Spectrograph (IRS) is one of three instruments to be flown in the Space Infrared Telescope Facility (SIRTF). Space Infrared Telescope Facility (SIRTF) The Space InfraRed Telescope Facility (SIRTF), the fourth and final element in NASA's family of "Great Observatories", has entered development. SIRTF consists of a 0.85-meter telescope and three cryogenically-cooled science instruments capable of performing imaging and spectroscopy in the 3 - 180 micron wavelength range. Incorporating the latest in large-format infrared detector arrays, SIRTF offers orders-of-magnitude improvements in capability over existing programs. While SIRTF's mission lifetime requirement remains 2.5 years, recent programmatic and engineering developments have brought a 5-year cryogenic mission within reach. A fast-track development schedule will lead to a launch in December 2001. SIRTF represents an important scientific and technical bridge to NASA's new Origins program. Space Interferometry Mission (SIM) SIM will be NASA's first space interferometer designed specifically for measuring the position of stars. SIM will utilize multiple telescopes placed along a 10-meter (33-foot) structure. Special Astrophysical Observatory of Russian Academy of Sciences (SAO RAS) SAO is Russia's main centre for ground-based space research. The Observatory is located in the South of Russia, in the Caucasus mountains of Karachaevo-Cherkesia. The basic instruments of the Observatory are the 6-meter optical telescope BTA (Big Alt-azimuth Telescope) and the 600-meter radio telescope RATAN-600. SPECTRUM UV is planned as a general purpose ultraviolet observatory. Phase A study activities are supported by the Space Agencies of Russia, Ukraine, Italy and Germany. Spectrum UV is planned to be launched round the turn of the century. Spectrum-X-Gamma Coordination facility (SXG. University of Harvard) Spectrum-X-Gamma (SXG) is an international high-energy astrophysics observatory which is being built under the leadership of the Russian Space Research Institute (IKI). The US SXG CF supports the US astronomical community in obtaining information about SXG, proposing for and making SXG observations, and performing archival research using the SXG archive Square Kilometer Array - Interferometer radio telescope project (SKA) This site provides information about the world-wide efforts to develop the next generation of radio telescope. Square Kilometre Array (SKA - Australian contribution) A web resource covering SKA scientific and engineering developments. Contains access to reports, meetings announcements, discussions of SKA issues, links to SKA related research. Stardial:an autonomous astronomical camera on the World Wide Web (Stardial) Stardial delivers images of the night sky nearly in real-time to the world wide web. It is used primarily for educational purposes. Its archive consists of images taken at 15 minute (sidereal) intervals since July 1996. The survey covers from 0 to -8 degrees declination to 12th magnitude. Highlights and possible classroom assignments are described. A space mission that will fly close to a comet and, for the first time ever, bring cometary material back to Earth STellar Astrophysics & Research on Exoplanets (STARE) STARE (STellar Astrophysics & Research on Exoplanets) uses precise time-series photometry to search for extrasolar giant planets transiting their parent stars. An important byproduct of STARE will be an unusually complete survey of variable stars within its selected fields-of-view. Stephen F. Austin State University Observatory (SFASU) Facilities, research, and personnel of the SFASU Observatory. The Steward Observatory Home Page provides information on the academic and research activities of the University of Arizona Department of Astronomy as well as information on the facilities of Steward Observatory. Stratospheric Observatory For Infrared Astronomy (SOFIA) The Stratospheric Observatory For Infrared Astronomy (SOFIA) will be a 2.5 meter, optical/infrared/sub-millimeter telescope mounted in a Boeing 747, to be used for many basic astronomical observations performed at stratospheric altitudes. The Facility will accommodate installation of different focal plane instruments, with in-flight accessibility, provided by investigators selected from the international science community. The Facility objective is to have an operational lifetime in excess of 20 years. SUBARU astronomical observatory Japan national optical-infrared telescope at the summit of Mauna Kea. The site includes astrophotographs from Subaru. Subaru Telescope at Hilo (NAOJ) The SUBARU is an 8.3-m diameter new-generation telescope being constructed and to be operated by the National Astronomical Observatory, under the Ministry of Education of Japan. Submillimeter Array (SMA) The Submillimeter Array (SMA), now under construction near the summit of Mauna Kea, was conceived as an exploratory instrument for high angular resolution observations at submillimeter wavelengths (1.3 to 0.3 mm). Submillimeter Polarimeter for Antarctic Remote Observing (SPARO) Mapping Interstellar Magnetic Fields from the South Pole. Submillimeter Receiver Laboratory (SAO) Submillimeter Telescope Observatory (SMTO) The Submillimeter Telescope Observatory (SMTO) is operated as a joint facility for the University of Arizona's Steward Observatory and the Max-Planck-Institut für Radioastronomie (Bonn). The SMTO is located on Emerald Peak of Mt. Graham, approximately 75 miles north-east of Tucson, Arizona. Submillimeter Wave Astronomy Satellite (SWAS) SWAS, the Submillimeter Wave Astronomy Satellite, is a pathfinding mission for studying the chemical composition of interstellar galactic clouds to help determine the process of star formation. Submillimetre Common-User Bolometer Array for the James Clerk Maxwell Telescope (SCUBA) SCUBA is a bolometer camera for the James Clerk Maxwell Telescope operating at submillimetre and millimetre wavelengths. Sudbury Neutrino Observatory (SNO at Queen's University) SNO is an astronomical neutrino observatory that is being built below ground in the deepest section of INCO Limited's Creighton Mine near Sudbury, Ontario. SNO is an international collaboration of scientists from Canada, USA and UK. Information services are available at * Queen's University * University of Guelph. Super-Kamiokande is a joint Japan-US collaboration to construct the world's largest underground neutrino observatory. Superconducting Tunnel Junction Detector Research (STJ) Such devices promise to yield the near-ideal astronomical photon-counting detector in which not just the location, but also the energy of each photon is recorded at extremely high efficiency. STJ detectors have previously been considered mainly for X-ray astronomy applications, but recent theoretical and laboratory research in the division has led to a dramatic breakthrough in extending the technique to visible and UV wavelengths where energy discrimination up until now has had to rely on filters or low efficiency dispersive optics. Supernova / Acceleration Probe (SNAP) The Supernova / Acceleration Probe (SNAP) Mission is expected to provide an understanding of the mechanism driving the acceleration of the universe. The satellite observatory is capable of measuring up to 2,000 distant supernovae each year of the three-year mission lifetime. Swedish 1-m Solar Telescope (NSST) 1m solar vacuum telescope at Roque de los Muchachos Observatory operated by the Royal Swedish Academy of Sciences. Swedish-ESO SUbmillimetre Telescope (SEST) Swift Gamma Ray Burst Explorer Swift is a three-telescoipe space observatory (gamma-ray telescope, X-ray telescope, and ultraviolet/optical telescope) for studying gamma ray bursts. It is a NASA MIDEX mission selected for launch in 2003. Sydney University Molonglo Sky Survey (SUMSS) SUMSS is a deep radio survey of the entire sky south of declination -30 degrees, made using the Molonglo Observatory Synthesis Telescope, operating at 843MHz and recording right-circular polarization. SUMSS matches (approximately) the resolution and depth of the NRAO-VLA Sky Survey (NVSS). The principal data products are mosaics which cover a 4x4 degree square on the sky. The centres of the mosaics mirror the NVSS centres in the north. The resolution is 45" x 45"/sin(dec), and the rms noise limit varies from 1.3 to 2mJy/beam (lower toward the south celestial pole). The survey began in March 1997 and will take eight years to complete. SUMSS is suported by funding from the Australian Research Council. The primary reference for a description of the survey is: Bock, D., Large, M. and Sadler, E. Taeduk Radio Astronomy Observatory (TRAO) Taeduk Radio Astronomy Observatory (TRAO) is part of the Korea Astronomy Observatory, which is operated under a cooperative agreement with the Ministry of Science and Technology. Telescope a Action Rapide pour les Objets Transitoires (TAROT) TAROT is an automatic, autonomous observatory whose first objective is the real-time detection of optical transient counterparts of cosmic gamma ray bursts. Telescope Array Project A project of ground-based detector for Astrophysics. Telescopio Infrarosso del Gornergrat (TIRGO) Italian national 1.5m telescope optimized for infrared observations, operated by CAISMI-CNR, Florence. Telescopio Nazionale Galileo - Italian National Telescope Galileo (TNG, La Palma) The Telescopio Nazionale Galileo is the national facility of the Italian astronomical community, set in the Canary island of La Palma (Spain). The Astronomical Observatory of Padova had the responsibility of its construction through the TNG Project Office. Tennessee State University 2-m Automatic Spectroscopic Telescope Project (2-m AST) This site details development of an 80-inch automatic telescope that Tennessee State University is developing for high-dispersion spectroscopy. It includes engineering reports and extensive pictures of the instrument. Terrestrial Planet Finder (Origins of Stars, Planets, and Life) The Terrestrial Planet Finder (TPF) is a key element of NASA Origins Program. It will study all aspects of planets: from their formation and development in disks of dust and gas around newly forming stars to the presence and features of those planets orbiting the nearest stars; from the numbers at various sizes, and places to their suitability as an abode for life. By combining the high sensitivity of space telescopes with the sharply detailed pictures from an interferometer, TPF will be able to reduce the glare of parent stars by a factor of more than one hundred-thousand to see planetary systems as far away as 50 light years. The Wilderness Center Astronomy Club (WCAC) Astronomy club in Canton, Ohio area. New observatory with refurbished 16" Ealing Cassegrain telescope. Planetarium and Educational programs. THEMIS - Heliographic Telescope for the Study of the Magnetism and Instabilities on the Sun (THEMIS) THEMIS (Télescope Héliographique pour l'Etude du Magnétisme et des Instabilités Solaires) is a new generation Franco-Italian solar telescope built by INSU/CNRS (France) and CNR (Italy). The main scientific goal for which it has been designed is the accurate determination of the vector magnetic field. Thueringer Landessternwarte Tautenburg (TLS) The observatory is running a 2m telescope which can be used in three different optical configurations: Schmidt telescope Cassegrain telescope Coude telescope Torun Radio Astronomy Observatory (TRAO) Torun Radio Astronomy Observatory (TRAO), now part of Torun Centre for Astronomy is an educational and research facility of the Nicolaus Copernicus University, Faculty of Astronomy and Physics, Torun, Poland. The Observatory main instrument is 32m modern design radio telescope usable up to 50 GHz. Presently equipped with cooled receivers for L and C bands is used extensively for VLBI, pulsar timing and spectroscopy. Since April 1998 Torun is the full member of the EVN. Transition Region And Coronal Explorer (TRACE) TRACE will enable solar physicists to study the connections between fine-scale magnetic fields and the associated plasma structures on the Sun in a quantitative way by observing the photosphere, transition region, and corona. U.S. Space Very Long Baseline Interferometry Project (U.S. Space VLBI) This project supports the VSOP (VLBI Space Observatory Programme) mission led by the Institute of Space and Astronautical Science in Japan, and the RadioAstron mission led by the Astro Space Center of the Lebedev Physical Institute in Russia. VSOP is scheduled for launch in September 1996, while RadioAstron is scheduled for launch in 1997. Each mission involves an orbiting 8-10 meter radio telescope dedicated to astronomical radio interferometry experiments using baselines formed between the spacecraft and a number of ground radio telescopes. A variety of information is now on line, describing the JPL Project, each of the space missions, and the science goals of the missions. Uhuru Satellite (GSFC. NASA) Uhuru was the first earth-orbiting mission dedicated entirely to celestial X-ray astronomy. It was launched on 12 December 1970 into an orbit of about 560 km apogee, 520 km perigee, 3 degrees inclination, with a period of 96 minutes. The mission ended in March 1973. UK Infra-Red Telescope (UKIRT) UK Schmidt Telescope - Anglo-Australian Observatory (UKST / AAO) UK Schmidt Telescope (UKST) The initial task of the UKST was to construct a photographic survey of the entire southern sky. The telescope still takes some 700 plates a year - about half for current surveys and the remainder taken at the request of research astronomers around the world. To date the UKST has taken over 17,000 plates, the plates are stored in the Plate Library at the Royal Observatory, Edinburgh (ROE) and represent a huge source of data for the astronomical community. Some 300 active research programmes make use of UKST plate material. Many plates are copied in the ROE Photolabs and sold as Sky Atlases or Teaching Packages. In addition to its photographic role the UKST also has a multi-object fibre spectroscopy system known as FLAIR. e-mail [email protected] Ultraviolet Imaging Telescope (UIT - Archives at STScI MAST) The Ultraviolet Imaging Telescope UIT was one of three ultraviolet telescopes on the ASTRO-1 mission flown on the space shuttle Columbia during 2-10 December 1990. The same three instruments were later flown on the space shuttle Endeavour from 3-17 March 1995, as part of the ASTRO-2 mission. Exposures were obtained on 70-mm photographic film in the 1200-3300 Å range using broadband filters and later digitized using a Perkin-Elmer microdensitometer. Image resolution was 3" over a 40' field of view. Overall, UIT-1 obtained 821 exposures of 66 targets, and UIT-2 obtained 758 images of 193 targets. Ulysses Mission (JPL) The Ulysses Mission is the first spacecraft to explore interplanetary space at high solar latitudes. Ulysses is a joint endeavor of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) of the USA. Instruments include: Magnetometer (VHM/FGM), Solar Wind Plasma Experiment (SWOOPS), Solar Wind Ion Composition Instrument (SWICS), Unified Radio and Plasma Wave Instrument (URAP), Energetic Particle Instrument (EPAC), Low-Energy Ion and Electron Experiment (HISCALE), Cosmic Ray and Solar Particle Instrument (COSPIN), Solar X-ray and Cosmic Gamma-Ray Burst Instrument (GRB) University of Bradford - Robotic Telescope The engineering in astronomy Team in the Department of Industrial Technology are currently working on low-cost fully-robotic telescopes. University of California Observatories - Lick Observatory (WWW) (UCO/Lick) Lick Observatory Anonymous ftp University of California, Irvine, Observatory (UCI Observatory) The University of California, Irvine, Observatory is located on campus. It consists of a computer-controlled telescope with a 24-inch primary mirror and numerous other portable telescopes. The instruments on the primary telescope include CCD cameras and a spectrograph. The Observatory is used primarily for undergraduate astronomy classes. In addition, Visitor Nights open to the general public are held quarterly, and special tours for community groups can be arranged. University of Denver Astronomy Mt.Evans Meyer-Womble Observatory located at 14,124 feet above sea level, on Mt.Evans in the Front Range of Colorado, used for infrared astronomy research. University of Hawaii IfA: 2.2m Telescope University of Louisville - Moore Observatory Moore Observatory is located in the Horner Wildlife Sanctuary near Louisville, KY. A computer-controlled 0.5 meter telescope, fiber optically coupled spectrograph, and wide field spectral imaging camera are used there to investigate physical processes in comets and low surface brightness emission nebulae. This resource describes the observatory and its environs, and provides a link to astrophysics research at the University of Louisville. University of Toronto Southern Observatory (UTSO) UTSO operates the 60cm Helen Sawyer Hogg Telescope located on Cerro Las Campanas in north-central Chile. This homepage provides information useful to potential users and others interested in our facility. Ventspils International Radioastronomy Center (VIRAC) The Ventspils 32-m antenna is the largest in the Baltics. At VIRAC, observations of solar and cosmic radio sources are carried out, as well as work in geophysics. VLBI experiments have been made, and a current goal is to join the European VLBI network. Very Large Array (VLA) The following resources are similar (same sort-key, different text): Very Large Array (VLA) Very Large Telescope Project (VLT, ESO) ESO is building what will be the World's largest optical telescope array, The Very Large telescope (VLT). The ESO Very Large Telescope will consist of four 8-meter telescopes which can work independently or in combined mode. In this latter mode the VLT provides the total light collecting power of a 16 meter single telescope, making it the largest optical telescope in the world. The four 8-m telescopes supplemented with 3 auxilliary 1 m telescopes may also be used in interferometric mode providing high angular resolution imaging. The useful wavelength range extends from the near UV up to 25 microns in the infrared. Very Long Baseline Array (VLBA) Very Small Array (VSA) The Very Small Array is an interferometer array designed to make images of the cosmic microwave background (CMB) radiation on angular scales around one degree. The VSA consists of an array of 14 small antennas, working at a frequency in the range 26-36 GHz, and will be sited at the Teide Observatory in Tenerife. Virgo Interferometer (VIRGO) VIRMOS (ESO-VLT Project) The VIRMOS project aims to deliver 2 spectrographs for the ESO- VLT . VIMOS is a visible imaging spectrograph with outstanding multiplex capabilities, allowing to take spectra of more than 800 objects simultaneously (10 arcsec slits), or spectroscopy of all objects in a 1x1 arcmin2 area. NIRMOS is a near-infrared imaging spectrograph with a multiplex of 180 (10 arcsec slits), and allows spectroscopy of all objects in a 30x30 arcsec2 area. Together VIMOS and NIRMOS allow to get spectroscopy from 0.37 to 1.8 microns, with unsurpassed efficiency for large surveys. Visible and Infrared Survey Telescope for Astronomy (VISTA) VISTA is the Visible and Infrared Telescope for Astronomy: a 4-m Wide Field Survey telescope for the Southern Hemisphere, being built at Cerro Paranal, close to ESO VLT, by a consortium of 18 UK universities. VLBI Antenna at Radio-Observatorio Espacial do Nordeste (ROEN) Site of Fortaleza, Brazil. VLBI Space Observatory Programme (VSOP) The VSOP (VLBI Space Observatory Programme) mission is led by the Institute of Space and Astronautical Science, in collaboration with the National Astronomical Observatory of Japan. The first VSOP satellite was successfully launched 12 February 1997 on the new ISAS M-V rocket from the Kagoshima Space Center. The satellite, renamed HALCA after its successful launch, sucessfully deployed an 8 meter diameter radio telescope in orbit on 27 & 28 February 1997. HALCA is in an elliptical Earth orbit, with an apogee height of 21,000km and a perigee height of 560km, which enables VLBI (Very Long Baseline Interferometry) observations on baselines up to three times longer than those acheivable on Earth. VLT Mid Infrared Imager Spectrometer (VISIR, ESO VLT) VLT Survey Telescope (VST) The VST project is a cooperation between the European Southern Observatory (ESO) and the Capodimonte Astronomical Observatory (OAC) for the study, design and construction of a wide field alt-az telescope of 2.6 m aperture, specialized for high quality astronomical imaging to be installed and operated on Cerro Paranal, next to ESO's Very Large Telescope (VLT). Vulcan Camera Project The Vulcan Camera Project, sponsored by NASA Ames Research Center, is designed to detect transits of large extrasolar planets using differential photometry. Vulcan uses a 15cm aperture refactor at Lick Observatory to image a wide field in which ~6000 stars are monitored for two months, in a search for the ~1% transit signal expect from a 51 Pegasi-type planet. Vulcan is a ground-based test-bed for the proposed Kepler Mission to detect Earth-sized exoplanets. WAVES : The Radio and Plasma Wave Investigation on the WIND Spacecraft (waves) WAVES radio astronomy instrument on the ISTP-Wind spacecraft. Westerbork Synthesis Radio Telescope (WSRT - ASTRON) The Westerbork Synthesis Radio Telescope is a linear 3 kilometer array located near the village of Westerbork in the North-East of the Netherlands. The WSRT consists of fourteen 25m dishes along a perfect east-west line. By combining these fourteen elements one can synthesize a radio telescope with a diameter of 3 kilometers. WFCAM - Wide Field Camera (UKIRT) WFCAM is an IR wide field camera for the UK Infrared Telescope on Mauna Kea. WFCAM will be operational as an IR imaging survey instrument in late 2002. The camera has been designed to maximize survey speed at J, H and K while retaining excellent image quality. Whipple Observatory (FLWO) Whole Earth Blazar Telescope (WEBT) The WEB Telescope (WEBT) is a network of optical observers who in concert have the capability to obtain continuous, high-temporal-density, optical monitoring of blazars. Whole Earth Telescope (WET) In 1986, astronomers from the University of Texas established a world--wide network of cooperating astronomical observatories to obtain uninterrupted time--series measurements of variable stars. The technological goal was to resolve the multi-periodic oscillations observed in these objects into their individual components; the scientific goal was to construct accurate theoretical models of the target objects, constrained by their observed behavior, from which their fundamental astrophysical parameters could be derived. This approach has been extremely successful, and has placed the fledgling science of stellar seismology at the forefront of stellar astrophysics. The following resources are similar (same sort-key, different text): Whole Earth Telescope (WET, site of University of Texas at Austin) The Whole Earth Telescope (WET) is a collaboration of astronomers who observe variable stars (white dwarfs and Delta Scuti stars) and cataclysmic variables Typically twice a year, we coordinate a global time-series photometry campaign at ~10 observatories worldwide such that our target objects are visible from the night side of the planet 24 hours a day Wide Field Infrared Explorer (WIRE) This is the website for NASA's Wide Field Infrared Explorer (WIRE). The primary purpose of WIRE was a four month infrared survey of the universe, focusing specifically on starburst galaxies and luminous protogalaxies. On 29 Mar 1999, the WIRE mission has been declared a loss. Wilcox Solar Observatory (WSO) The Wilcox Solar Observatory began daily observations of the Sun's global magnetic field in May 1975, with the goal of understanding changes in the Sun and how those changes affect the Earth; this is now called space weather. Now low-resolution maps are also made of the Sun's magnetic field each day, as are observations of solar surface motions. The observatory is located in the foothills just west of the Stanford University campus. Robotic observatory for small telescopes located in southeastern Arizona hosting telescopes from other institutions for a fee. See our Web site for details. Our own scientific interests are NEO's and minor planet astrometry and photometry. Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) was a pioneering effort to explore polarization and photometry in the ultraviolet (UV) spectrum. It was the first and most comprehensive effort to exploit the unique powers of polarimetry at wavelengths not visible on Earth. The instrument was designed and built at the University of Wisconsin Space Astronomy Laboratory in the 1980's. WUPPE flew on two NASA Space Shuttle missions: ASTRO-1 and ASTRO-2. WIYN, from Indiana University Wolfgang-Amadeus, The University of Vienna Twin Automatic Photoelectric Telescope (APT) We operate two robotic 75-cm telescopes for photoelectric photometry at Fairborn Observatory in the Sonoran desert near Tucson, Arizona. Not only are the telescopes automatic, but the observatory itself is automatic. A site-control computer monitors weather sensors, operates the observatory roof, and provides a nightly report to the observatory staff, who are located in Vienna, Austria. Wyoming Infrared Observatory (WIRO) X-Ray Timing Explorer (XTE. GSFC.NASA) The Rossi X-ray Timing Explorer is a Goddard mission which was launched on December 30th, 1995. RXTE is designed to facilitate the study of time variability in the emission of X-ray sources with moderate spectral resolution. Time scales from microseconds to months are covered in an instantaneous spectral range from 2 to 250 keV. It is designed for a required lifetime of two years, with a goal of five years. XMM-Newton Science Operations Centre (XMM, ESA) ESA s X-ray Multi Mirror mission XMM-Newtion is the second Cornerstone in ESA's Long Term Scientific Programme. With a large collecting area of its mirrors and the high sensitivity of its cameras, XMM-Newton is expected to increase radically our understanding of high-energy sources - clues to a mysterious past, and keys to understanding the future of the Universe. The European Space Agency's X-ray Multi-Mirror satellite is the most powerful X-ray telescope ever placed in orbit. It has an unprecedented sensitivity and the mission will help solve many cosmic mysteries, ranging from enigmatic black holes to the formation of galaxies. Yerkes Observatory (University of Chicago) Yerkes Observatory in Williams Bay Wisconsin hosts the 40" refractor, a 41" reflector, a 24" Boller & Chivens reflector, a 10" educational telescope, and support facilities. The 41" telescope is used for research including adaptive optics studies.

Crescent ♌ Leo Moon phase on 5 July 2016 Tuesday is Waxing Crescent, 1 day young Moon is in Cancer.Share this page: twitter facebook linkedin Previous main lunar phase is the New Moon before 1 day on 4 July 2016 at 11:01. Moon rises in the morning and sets in the evening. It is visible toward the southwest in early evening. Lunar disc appears visually 0.1% narrower than solar disc. Moon and Sun apparent angular diameters are ∠1885" and ∠1887". Next Full Moon is the Buck Moon of July 2016 after 14 days on 19 July 2016 at 22:57. There is medium ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at very acute angle, so their combined tidal force is moderate. The Moon is 1 day young. Earth's natural satellite is moving from the beginning to the first part of current synodic month. This is lunation 204 of Meeus index or 1157 from Brown series. Length of current 204 lunation is 29 days, 9 hours and 44 minutes. It is 2 hours and 35 minutes shorter than next lunation 205 length. Length of current synodic month is 3 hours and 1 minute shorter than the mean length of synodic month, but it is still 3 hours and 9 minutes longer, compared to 21st century shortest. This New Moon true anomaly is ∠48.9°. At beginning of next synodic month true anomaly will be ∠77.9°. The length of upcoming synodic months will keep increasing since the true anomaly gets closer to the value of New Moon at point of apogee (∠180°). 4 days after point of perigee on 1 July 2016 at 06:45 in ♉ Taurus. The lunar orbit is getting wider, while the Moon is moving outward the Earth. It will keep this direction for the next 7 days, until it get to the point of next apogee on 13 July 2016 at 05:24 in ♏ Scorpio. Moon is 380 287 km (236 299 mi) away from Earth on this date. Moon moves farther next 7 days until apogee, when Earth-Moon distance will reach 404 272 km (251 203 mi). 9 days after its descending node on 26 June 2016 at 05:28 in ♓ Pisces, the Moon is following the southern part of its orbit for the next 3 days, until it will cross the ecliptic from South to North in ascending node on 9 July 2016 at 01:41 in ♍ Virgo. 23 days after beginning of current draconic month in ♍ Virgo, the Moon is moving from the second to the final part of it. 1 day after previous North standstill on 3 July 2016 at 20:06 in ♊ Gemini, when Moon has reached northern declination of ∠18.598°. Next 12 days the lunar orbit moves southward to face South declination of ∠-18.569° in the next southern standstill on 18 July 2016 at 03:41 in ♑ Capricorn. After 14 days on 19 July 2016 at 22:57 in ♑ Capricorn, the Moon will be in Full Moon geocentric opposition with the Sun and this alignment forms next Sun-Earth-Moon syzygy.

What is a black hole? Do they really exist? How do they form? How are they related to stars? What would happen if you fell into one? How do you see a black hole if they emit no light? What’s the difference between a black hole and a really dark star? Could a particle accelerator create a black hole? Can a black hole also be a worm hole or a time machine? In Astro 101: Black Holes, you will explore the concepts behind black holes. Using the theme of black holes, you will learn the basic ideas of astronomy, relativity, and quantum physics. After completing this course, you will be able to: • Describe the essential properties of black holes. • Explain recent black hole research using plain language and appropriate analogies. • Compare black holes in popular culture to modern physics to distinguish science fact from science fiction. • Describe the application of fundamental physical concepts including gravity, special and general relativity, and quantum mechanics to reported scientific observations. • Recognize different types of stars and distinguish which stars can potentially become black holes. • Differentiate types of black holes and classify each type as observed or theoretical. • Characterize formation theories associated with each type of black hole. • Identify different ways of detecting black holes, and appropriate technologies associated with each detection method. • Summarize the puzzles facing black hole researchers in modern science. Introduction to Black Holes -Hello and welcome to the first module of Astro 101! In this module, you will become familiar with the basic structure of a black hole, learn the terminology used to describe them, and explore the history of black hole physics. Life and Death of a Star -Stars are the progenitors of black holes. In this module the student will learn about the lifecycle of stars, how stars produce energy, and how they radiate away energy. We will explore the death of stars, and what is produced by the death of stars, on all scales ; from the building blocks of life (carbon) to black holes. The Structure of Spacetime -What happens if you travel close to the speed of light? What happens to the passage of time as you fall towards a black hole? This module will explore relativity. We look at the many ways black holes affect the universe around them from discussions of reference frames through to the change in the passage of time as you approach a black hole. Sizing Up Black Holes -So far discussion has focussed on either the general case for black holes, of the stellar mass variety (endpoint of a star's life). In this module students will explore the various sizes of black holes and their measurable properties. Students will learn that there are four major types of astrophysical black holes (primordial/mini black hole’s, stellar mass, intermediate mass and supermassive black holes), and discover current theories on their formation, and what might feed them. Students will also gain an knowledge of ‘no-hair’ theorem and gravitational lensing. We will also explore the formation of supermassive black holes, intermediate mass black holes, and mini black holes in particle accelerators. Approaching a Black Hole -What would you see as you approached a black hole, using a black hole binary as a vehicle to explore black holes? In this module students will follow material as it is transferred from a companion star to a black hole via Roche lobe overflow or wind fed accretion. They will then follow that material down through the accretion disc to explore tidal forces to learn about the ways in which black holes can rip apart surrounding material. This material will then pass through the innermost stable orbit of the disc, before falling in. Students will also get the opportunity to look at jets - the outflow of material from the innermost regions of this structure. Module Objective: Introduce properties of black holes from the outside in, through the context of a journey into the event horizon of a black hole. What would we see as we are far away? What will we see and experience as we get closer? What is a disc? What is a jet? Crossing the Event Horizon -Module Description: What would happen if you fell into a black hole? In this module students continue on their journey through a black hole binary system, from the innermost stable orbit of the accretion disc to the singularity itself. Students will learn about the structure of a basic black hole, as well as rotating black holes. Students will explore the concept of wormholes and singularities. Module Objectives: Students will learn about the innermost region around a black hole, about its lack of surface and about the presence and definition of an event horizon. Students will also explore the impact that spin can have on this region, and how it is measured. Finally they will look inside the event horizon to discover the basic concepts of singularities and wormholes. Inside a Black Hole -What is in a black hole? This module will start to explore the theoretical side of black hole physics. You will receive a basic introduction to relevant topics of Quantum Mechanics and thermodynamics with the aim of understanding current black hole debates among the giants of the field. Hunting for Black Holes -If black holes absorb all light, how do we see them? In this module, you will explore how astronomers observe real black holes, from studies of accretion discs and jets to the study of material orbiting a black hole. Our Eyes in the Skies -Black holes change over time. This module will focus on how and why black holes change as well as how we look for these changes. Riding the Gravity Wave -How do you study a black hole that has no visible companion? In this module the student will be introduced to gravitational radiation. With the 2016 LIGO discovery of gravitational waves, a whole new branch of astronomy has been opened.

Now using an ion thruster that had been powered off since October, Dawn continues to make steady progress on its journey deeper into space. In this phase of the mission, each day of thrusting changes the probe's speed by 6.7 meters/second (15 miles/hour). Dawn will operate its ion thrusters for a total of more than 5 years, providing the extraordinary boost required to orbit both main belt asteroid Vesta and dwarf planet Ceres in the quest to understand the dawn of the solar system. Some readers may be reminded of the prophetic sagacity of Tardigrade the Celeritous, who, with uncanny prescience (and, at the time, abstruseness), is believed to have said that the journey of 11 kilometers/second (25,000 miles/hour) begins with a single day of thrusting. The spacecraft is outfitted with three ion thrusters but will never use more than one at a time. In October and November, during the initial checkout phase of the mission, all three thrusters were tested and confirmed to be healthy and ready for operation. Following the flight plan, thruster #3 was the first to propel the craft in its interplanetary cruise phase, which began on December 17. In the 184 days from the beginning of interplanetary cruise until ion thruster #1 took over, thruster #3 operated for a total of 149 days, flawlessly changing Dawn's orbit around the Sun. Each week the thrust was turned off for a few hours when the spacecraft turned to point its main antenna to Earth, and a few days every month or so have been devoted to other, non-thrusting activities. (Readers are encouraged to review the logs posted since December to remind themselves of such activities. That might yield an unexpected reward, as it may now be revealed that the text of those logs contains a highly encrypted message with information of astonishing import. If you find it, please let this writer know, as he has absolutely no idea what it is!) The effect of thruster #3's operation during this mission phase was to change the spacecraft's speed by 0.99 kilometers/second (,2200 miles/hour). Thanks to the exceptionally high efficiency of the ion propulsion system, Dawn's solar system xenon footprint in accomplishing this was less than 40 kg (87 pounds). (Note also that its carbon footprint was 0.) Dawn's ion thruster An engineering model of one of Dawn's three ion thrusters, which use electrical power to ionize xenon gas and accelerate it to a speed 10 times that of chemical engines. Each thruster is 30 centimeters (12 inches) in diameter and is steerable in two axes. Switching from one thruster to another is simple (to the extent that anything is simple for early 21st century humans controlling a spacecraft in deep space). The potential complication in this case was explained in the previous log. Our readers survey (conducted by Telepathic Business Services, Inc. when their employees had time between major poker competitions) shows that three readers do not fully recall the details and will not refer to that log, so the issue is summarized here. The three ion thrusters point in different directions on the spacecraft. To provide thrust in the correct direction in space, Dawn has to rotate to aim the designated thruster in that direction. The use of thruster #1 now requires the craft to assume an orientation quite different from any that had been experienced before, and engineers were not confident certain components would remain within their required temperature limits when the Sun shone on them. Last month's test, in which the spacecraft spent a few hours pointing in the required direction, provided some of the data needed to establish when it would be safe to commit to the use of thruster #1 for long periods of time. The results agreed with previous analyses, which had shown that all the components would remain in their prescribed temperature ranges if thruster #1 were put to use this month. Probably. Probably? That "probably" was not good enough. Ever-cautious mission controllers were not sufficiently confident to let the spacecraft remain in the new orientation for a week at a time, because there were a few components whose temperatures still could not be predicted well enough. The analyses were conclusive that the temperatures would be safe for more than 24 hours, as it takes a long time for that hardware to heat up. Therefore, the team devised a new approach. A typical set of commands for five weeks of operation with thruster #1 was formulated. In addition, engineers prepared instructions for storage onboard to stop thruster #1, rotate to the thruster #3 orientation, resume thrusting, and perform all the other associated functions, the description of which is precluded by laws on profoundly incomprehensible prose. (While such laws are applicable only in the vicinity of supermassive stars, we obey them out of consideration for such regions of our distribution.) The instructions were structured so that only a single, brief message from Earth would be needed to trigger the switch back to thruster #3. On June 18, the spacecraft turned from pointing its antenna to Earth to aim thruster #1 in the correct direction and initiated thrusting. A Deep Space Network antenna that was available was scheduled to listen in to the spacecraft on June 19. Dawn was programmed to use one of its small antennas, with a very broad radio beam, to transmit temperature measurements. Dawn's terrestrial team members receiving the data found the results to be much as expected. As predicted, the temperatures had not yet stabilized, and all were within the desired ranges. When they had about two hours of measurements in hand, engineers were able to predict with high confidence what the final temperatures would be. This confirmed that continued operation was safe, so there was no need to switch back to thruster #3. (Providing the spacecraft with the capability to make that decision, while that might seem pretty neat, would have required more work than the neatness would have merited.) As some may recall from long, long ago (to be specific, eight paragraphs ago), several days of coasting are included in the flight plan occasionally. Activities for some of those times are planned long in advance. Other such periods are held in reserve in case mission controllers identify the need for some previously unplanned work that could not be accommodated in the normal schedule. June 16 - 18 was one such interval. The mission has been going so smoothly, however, that no special activities were required then. The team did take advantage of the extra time that the primary antenna was pointed to Earth to clean up some file buffers and perform other maintenance on some of the spacecraft's computers. With the mission continuing so well, the Dawn team can devote much of its attention to preparing for future events. Although the Dawn project has no specific plans, readers may rest assured that the team members, as with their fellow residents of Earth, are completing personal plans to commemorate the centennial of the Tunguska event on June 29 (the event occurred on June 30 in Siberia's time zone). The next item of interest occurs on June 30, when the spacecraft exceeds the outermost reaches of the orbit of Mars; the probe will be farther from the Sun than that planet ever travels. Earth reaches its greatest distance from the Sun on July 4, when it will be almost 1.7% farther than its average distance. (On January 2, it was about 1.7% closer than average.) Then even as Earth begins a slow fall toward the Sun (a trend that will continue until next January), Dawn will continue its climb outward. On July 10, the robotic explorer will be twice as far from Earth as Earth will be from the Sun. At that time it will be 304 million kilometers (189 million miles) from the planet it left on a lovely dawn in September 2007. This blink animation consists of two 14-minute exposures. The faint speck that moves between the two images is the Dawn spacecraft, a million kilometers from Earth (about three times the Earth-Moon distance), and moving very fast. The telescope tracked Dawn during the long exposures, so the stars in the field of view form long and much brighter trails; the spacecraft glinted at only 20th magnitude at the time of the observation. At these extraordinary distances, humankind (and even some of our other readers) does not have the technology to see the spacecraft. Indeed, Dawn is barely discernible in a pair of portraits taken when it was more than 300 times closer to Earth. Yet some who follow the mission might enjoy gazing in the direction of the probe as they contemplate its journey deeper into space and the ambitious and exciting mission that lies ahead. For those in the continental United States, the spacecraft will be between 3° and 5° northeast of the moon in the evening of July 6 as the moon is approaching the western horizon. (In other words, Dawn will appear to be 6 to 10 times the moon's diameter away, north and higher in the sky.) Although quite invisible to your eyes, in that direction your mind may be able to see with great clarity one of your planet's envoys to the cosmos. With a blue-green trail of xenon ions behind it and appointments with distant, uncharted, alien worlds ahead of it, Dawn will be silently and contentedly carrying out its mission to extend our reach into space and to help fulfill our passionate search for knowledge and our yearning for adventure. Dawn is 286 million kilometers (178 million miles) from Earth, or more than 760 times as far as the moon and 1.88 times as far as the Sun. Radio signals, traveling at the universal limit of the speed of light, take 32 minutes to make the round trip.

Volume 518, July-August 2010Herschel: the first science highlights |Number of page(s)||15| |Section||Stellar structure and evolution| |Published online||26 August 2010| Do Wolf-Rayet stars have similar locations in hosts as type Ib/c supernovae and long gamma-ray bursts?* Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark e-mail: [email protected] 2 The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, 10691 Stockholm, Sweden 3 Department of Physics, University of Warwick, Coventry CV4 7AL, UK 4 Department of Astronomy & Astrophysics, University of California, Santa Cruz, CA 95064, USA 5 Sophie & Tycho Brahe Fellow Accepted: 31 March 2010 Aims. We study the distribution of Wolf-Rayet (WR) stars and their subtypes with respect to their host galaxy light distribution. We thus want to investigate whether WR stars are potential progenitors of stripped-envelope core-collapse supernovae (SNe) and/or long-duration gamma-ray bursts (LGRBs). Methods. We derived the relative surface brightness (fractional flux) at the locations of WR stars and compared with similar results for LGRBs and SNe. We examined two nearby galaxies, M 83 and NGC 1313, for which a comprehensive study of the WR population exists. These two galaxies contain a sufficiently large number of WR stars and sample different metallicities. To enable the comparison, the images of the galaxies were processed to make them appear as they would look at a higher redshift. The robustness of our results against several sources of uncertainty was investigated with the aid of Monte Carlo simulations. Results. We find that the WC star distribution favours brighter pixels than the WN star population. WC stars are more likely drawn from the same distribution as SNe Ic than from other SN distributions, while WN stars show a higher degree of association with SNe Ib. It can also not be excluded that WR (especially WC) stars are related to LGRBs. Some differences between the two galaxies do exist, especially in the subtype distributions, and may stem from differences in metallicity. Conclusions. Although a conclusive answer is not possible, the expectation that WR stars are the progenitors of SNe Ib/c and LGRBs survives this test. The trend observed between the distributions of WN and WC stars, as compared to those of SNe Ib and Ic, is consistent with the theoretical picture that SNe Ic result from progenitors that have been stripped of a larger part of their envelope. Key words: supernovae: general / stars: Wolf-Rayet / gamma-ray burst: general Table A.1 is only available in electronic form at http://www.aanda.org © ESO, 2010 Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform. Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days. Initial download of the metrics may take a while.

The first CubeSats launched in 2003, and in less than a decade, more than 100 had reached orbit. The aerospace industry has debated whether the 2kg to 15kg microsatellites are a fad, a toy, or a disruptive technology that will change they way we ultimately observe and study Earth and the rest of the Solar System. However, what is now beyond doubt is that the first CubeSats have gone interplanetary. On Saturday, after the launch of the InSight probe to Mars, NASA received signals from the Mars Cube One, or MarCO-A and -B satellites. The signals indicated that the twin spacecraft had retained enough charge in their batteries to deploy their own solar arrays, stabilize themselves, pivot toward the Sun, and turn on their radios. The twin MarCO satellites are not critical to the success of the InSight lander, they instead have their own separate mission to test the feasibility of CubeSats in deep space. They will follow InSight on its interplanetary trajectory to Mars and attempt to track the larger spacecraft’s descent and landing on Mars in November. "We’re nervous but excited," said Joel Krajewski of NASA’s Jet Propulsion Laboratory and MarCO’s project manager. "A lot of work went into designing and testing these components so that they could survive the trip to Mars and relay data during InSight’s landing. But our broader goal is to learn more about how to adapt CubeSat technologies for future deep-space missions." Scientists are eager to see how well the CubeSats work because they have the potential to revolutionize how we study the Solar System. Larger satellites, weighing hundreds of kilograms to several tons, are more complex and cost exponentially more to build than CubeSats. With their much greater mass, they also require larger, more powerful rockets to reach their intended targets—and they also cost more. If CubeSats can perform significant amounts of science, they could be launched in swarms to planets in the outer Solar System to gather intelligence. Moreover, if one or two failed out of that swarm, they would be relatively inexpensive to replace. By comparison, NASA is developing a six-ton "Clipper" satellite that will launch to Jupiter’s Moon of Europa as early as 2022. This mission will cost as much as $3 billion and includes eight different science instruments. If the MarCo satellites work at Mars, scientists will be able to begin to consider how much of that science could be done with smaller, much cheaper options.

« PreviousContinue » The density of the sun is only about one-fourth that of the earth, or 1.43 that of water, so that the weight of a body transferred from the earth to tho sun would not be increased in proportion to the comparative size of the two. On account also of the vast size of the sun, its surface is so far from its centre that the attraction is largely diminished, since that decreases, we remember, as the square of the distance. However, a man weighing at the earth's equator 150 lbs., at the sun's equator would weigh about 4,080 lbs.,—a force of attraction that would inevitably and instantly crush him. At the earth's equator a stone falls 16 feet the first second; at the sun's equator it would fall 437 feet. ^""telescopic Appeabance Of The Sun: Sun-spots.— We may sometimes examine the sun at early morning or late in the afternoon with the naked eye, and at midday by using a smoked glass. The disk will appear to us perfectly distinct and circular, and with no spot to dim its brightness. If we use, however, a telescope of moderate power, taking the precaution to properly shield the eye with a colored eye-piece, we shall find its surface sprinkled with irregular spots, somewhat as shown in the accompanying figure. Curious opinions concerning solar spots.—The natural purity of the sun seems to have been formerly an article of faith among astronomers, and therefore on no account to be called in question. Scheiner, it is said, having reported to his superior that he "had seen spots on the sun's face, was abruptly dismissed with these remarks: "I have read Aristotle's writings from end to end many times, and I assure you I do not find anything in them similar to that which you mention. Go, my son, tranquillize yourself; be assured that what you take for spots are the faults of your glasses or your own eyes." ^ ""^ Discovery of the solar spots.—They seem to have been noticed as early as 807 A. D., although the telescope was not invented until 1610, and Galileo discovered the solar spots in the following year. We read in the log-book of the good ship Eichard of Arundell, on a voyage, in 1590, to the coast of Guinea, that "on the 7, at the going downe of the sunne, we saw a great black spot in the sunne; and the 8 day, both at rising and setting, we saw the like,—which spot to me seeming was about the bignesse of a shilling, being in 5 degrees of latitude, and still there came a great billow out of the souther board." ^ Number and location of spots. — Sometimes, but rarely, the disk is clear. During a period of ten years, observations were made on 1982 days, on 372 of which there were no spots seen. As many as two hundred spots have been noticed at one time. They are found in two belts, one on each side of the equator, within not less than 8° nor more than 35° of latitude. They seem to herd together—the length of the straggling group being generally parallel to the equator. The size of the spots.—It is not uncommon to find a spot with a surface larger than that of the earth. / Schroter measured one more than 29,000 miles in diameter. Sir J. "W. Herschel calculated that one which he saw was 50,000 miles in diameter. In 1843 one was seen which was 14,816 miles across, and was visible to the naked eye for an entire week. On the day of the eclipse in 1858, a spot over 107,000 miles broad was distinctly seen, and attracted general attention in this country. Some who read this paragraph will doubtless recall its ap pearance. In 1839, Captain Davis saw one which he computed was not less than 186,000 miles long, and had an area of twenty-five billion square miles. If these are deep openings in the luminous atmosphere of the sun, what an abyss must that be at "the bottom of which our earth could lie like a boulder in the crater of a volcano!" spots consist of distinct parts.—From the accompanying representation it will be seen that the spots generally consist of one or more dark portions called the umbra, and around that a grayish portion styled the penumbra (pcne, almost, and umbra, black).— Sometimes, however, umbrae appear without a penumbra, and vice versa. The umbra itself has generally a dense black centre, called the this, the umbra is sometimes divided by luminous bridges. The spots are in motion.—They change from day to day; but they all have a common movement. About fourteen days are required for a spot to pass across the disk of the sun from the eastern side or limb to the western; in fourteen days it reappears, changed in form perhaps, but generally recognizable. The spots change their rapidity and apparent form as tliey pass across the disk.—A spot is seen on the eastern limb; day by day it progresses, with a gradually increasing rapidity, until it reaches the cen tre; it now gradually loses its rapidity, and finally disappears on the western limb. The diagram illustrates the apparent change which takes place in the form. Suppose at first it is of an oval shape; as it approaches the centre it apparently widens and becomes circular. Having passed that point, it becomes more and more oval until it disappears. This change in the spots proves the sun's rotation on its axis.—These changes can be accounted for only on the supposition that the sun revolves on its axis: indeed, they are the precise effects which the

NASA announced exciting news today that the Kepler space telescope has identified the most ‘earth like’ planet to date. So what does this actually mean? And is it really that exciting? This is a breakthrough for Kepler, because although it has discovered thousands of exoplantes (planets orbiting other stars) since 2009, only 12 of these have been remotely Earth-like, with a size less than double our own planet. In addition, these have all been found orbiting dwarf stars with far lower luminosity than our sun. Kepler 452b is different: it orbits a G class star which has a similar temperature and mass to our sun, although it is 20% brighter. The planet is less than twice earth’s size and has an orbit very similar to our Earth, and so it sits comfortably within the ‘habitable zone’ that allows the essential basic conditions for life – most important of which is the presence of liquid water. This is often called the ‘goldilocks’ zone because it describes an orbit not to close (too hot) and not to far away (too cold) for liquid water to exist. Come in Kepler The surface of Kepler 452b receives 10% more solar energy than Earth, but this is probably not prohibitive for photosynthetic life similar to our own. It has also been in the habitable zone for billions of years longer than Earth and so the timeframe for life to evolve exceeds that of Earth. Regardless of whether Kepler452b supports life, I think what is truly exciting is that this is really the nearest thing to Earth that humans have ever found – and it really raises the stakes in the debate about whether or not we are alone in the universe. I suppose what everyone wants to know is: Could humans survive on Kepler 452b? Possibly, we would get quite a suntan from brighter star, and the gravity is much greater but probably not be prohibitive to us physiologically. The the jury is still out as to whether it has a rocky liquid or gaseous surface – so that may require some adaptation! There is of course also the issue of getting there. If we traveled at the speed of the fastest human-constructed spacecraft (NASAs New Horizons) it would still take around 94 million years to reach Kepler 452b! This image shows the scale of Kepler452b’s solar system (and an earlier discovery Kepler 186) relative to our own (Image credit: NASA):

For the past nine months, Curiosity has been acting as a stunt double for astronauts, exposing itself to the same cosmic radiation humans would experience following the same route to Mars1. “Curiosity has been hit by five major flares and solar particle events in the Earth-Mars expanse,” says Don Hassler of the Southwest Research Institute in Boulder, Colorado. “The rover is safe, and it has been beaming back invaluable data.” Unlike previous Mars rovers, Curiosity is equipped with an instrument that measures space radiation. The Radiation Assessment Detector, nicknamed “RAD,” counts cosmic rays, neutrons, protons and other particles over a wide range of biologically-interesting energies. RADs prime mission is to investigate the radiation environment on the surface of Mars, but NASA turned it on during the cruise phase so that it could sense radiation en route to Mars as well. Curiosity’s location inside the spacecraft is key to the experiment. “Curiosity is riding to Mars in the belly of the spacecraft, similar to where an astronaut would be,” explains Hassler, RAD’s principal investigator. “This means the rover absorbs deep-space radiation storms the same way a real astronaut would.” Even supercomputers have trouble calculating exactly what happens when high-energy cosmic rays and solar energetic particles hit the walls of a spacecraft. One particle hits another; fragments fly; the fragments themselves crash into other molecules. “It’s very complicated. Curiosity has given us a chance to measure what happens in a real-life situation.” Hassler says the walls of the Mars Science Lab spacecraft have performed as expected: Only the strongest radiation storms have made it inside. Moreover, charged particles penetrating the hull have been slowed down and fragmented by their interaction with the spacecraft’s metal skin.

Albireo is a double star located in the constellation of Cygnus, being the fifth brightest star in the constellation. The primary star is yellow and makes a striking contrast with its blue, yet fainter companion. Key Facts & Summary - Albireo is located at around 430 light-years / 133 parsecs away from the Sun. - The star system has an apparent magnitude of 2.90 and an absolute magnitude of around -2.45. - The primary star, Albireo Aa, is believed to be itself a triple star system. - Albireo Aa is a bright-yellow giant star of spectral type K2II. It has an apparent magnitude of 3.18 and an absolute magnitude of -2.45. - Albireo Aa has around 14.52 solar masses and a radius of around 69 times that of the Sun. - Albireo Aa is cooler than our sun, at around 4.270 K average surface temperatures, but it is around 1.200 times brighter than our sun. - Albireo Aa is a slow spinner, having a rotational velocity of around 1.4 km / 0.8 mi per second. - The secondary star, Albireo B, is a blue-white main-sequence star of spectral type B8Ve. It has an apparent magnitude of 5.11. - Albireo B has around 3.84 solar masses and a radius of around 2.59 times that of the Sun. - Albireo B is much hotter than Albireo Aa, and the Sun combined. It has average surface temperatures of around 13.200 K. - Albireo B is around 230 times brighter than our sun, and it has been estimated to be much younger, at around 100 million years. - Albireo B is surrounded by a circumstellar disk of gas due to its mass loss rate, influenced by its fast rotational velocity of 250 km / 155 mi. - One of the two stars orbiting around Albireo Aa, is another blue-white star, but of spectral type B8:p. It is designated Albireo Ac and has an apparent magnitude of 5.82. - Albireo Ac is 3.84 times more massive than our Sun, and 950 times brighter. It is separated by Albireo Aa at a distance of around 40 AU. Albireo, though not the second-brightest in its constellation, is designated as Beta Cygni. It is actually fainter than Gamma Cygni, Delta Cygni, and Epsilon Cygni. Apart from this, the star’s name comes from a misunderstanding of the words “ab ireo.” This was a description of the constellation of Cygnus in the 1515 Almagest. The origin is believed to come from the Greek word “ornis,” which was the name of the constellation, and later became “urnis” in Arabic. It was translated into Latin due to an error, it was believed that the name referred to Erysimon, the Greek name for hedge mustard, and thus it became ireo – the Latin equivalent to hedge mustard. Thus “ab ireo” was eventually viewed as a miscopy and changed to al-bireo. It is unknown if the star’s in the Albireo star system formed at the same time or not. Apart from the others, Albireo B has been estimated to have around 100 million years, much younger than our sun. It is also unknown if Albireo B is truly gravitationally bound to Albireo Aa. The stars though, likely formed from a nebula or molecular cloud of gas and dust millions of years ago. Gravity pulled the swirling gas and dust together to form the Albireo stars. Distance, Size, and Mass Albireo is located at around 430 light-years / 133 parsecs away from the Sun. It is one of the closest beautifully and striking contrasted star system to Earth. The star can be seen with the naked eye, appearing as a single star though through smaller telescopes Albireo B may be distinguished. The primary star, Albireo Aa, is 14.52 solar masses, and a radius around 69 times that of the Sun. The secondary star, Albireo B, has 3.84 solar masses and a radius of around 2.59 times that of the Sun. The third star, Albireo Ac, is 3.84 times more massive than our Sun and its radius is currently unknown. The fourth star’s physical attributes are also unknown. The primary star, Albireo Aa, has two companion stars separately from Albireo B. Albireo Aa has an apparent magnitude of 3.18 and an absolute magnitude of -2.45. Albireo Aa is cooler than our sun, at around 4.270 K average surface temperatures, but it is around 1.200 times brighter than our sun. Albireo Aa is a slow spinner, having a rotational velocity of around 1.4 km / 0.8 mi per second. One of its companion stars is Albireo Ac, which is 3.84 times more massive than our Sun, and 950 times brighter. Albireo Ac has an apparent magnitude of 5.82 and an absolute magnitude of -0.25. The other companion’s physical characteristics are unknown. Albireo B, on the other hand, has an apparent magnitude of 5.11 and is much hotter than Albireo Aa, and the Sun combined. It has average surface temperatures of around 13.200 K, or 2.2 times hotter than our Sun. Albireo B is around 230 times brighter than our sun and is surrounded by a circumstellar disk of gas due to the fact that it spins very fast, at an estimated 250 km / 155 mi per second, thus it loses its mass very fast. Albiero Aa and B are separated by around 34.3 arcseconds. It is unknown if they are truly gravitationally bound to one another, but if they are, it would take around 75.000 years for them to complete one orbit. Albiero Ac is separated by Albiero Aa at around 0.4 arcseconds / 40 AU on average, while Albiero Ab was only 0.1 arcseconds away when it was discovered, and now it is currently 0.0 arcseconds, thus it is impossible to resolve the pair. Albiero Ac and Aa complete one orbit around each other once every 100 years or so. Both Albiero Ac and Albiero B appear blue-white in color while Albiero Aa is orange / bright-yellow. Albiero is located in the constellation of Cygnus, the celestial Swan. It is the fifth brightest star in the constellation and the faintest star which forms the summer asterism known as the Northern Cross. The Northern Cross is formed by Deneb – marking the top of the cross, and also the celestial tail of the Swan. Gamma Cygni, and Albiero outline the pole of the cross. Epsilon Cygni and Delta Cygni form the crossbeam. The constellation of Cygnus is the 16th largest in the night sky. For observers in the Southern Hemisphere, it is the most visible during the month of September, while for those in the Northern Hemisphere, from June to December. Due to the mass of Albiero Aa, it is considered a supernova candidate. It is difficult to predict when this will happen however, other studies suggest that the star will be the brightest in the night sky in the year 3.870.000. It will come within 80 light-years of the solar system. In the year 4.610.000, it will shine at magnitude -0.52, a little fainter than Canopus today. Did you know? - The two components of the primary star were discovered in the late 19th century after analyzing its spectrum. They were listed as HD 183912 and HD 183913 in 1923. - Cygnus is one of the Greek constellations, which first appeared in Ptolemy’s Almagest in the 2nd century C.E. - In medieval Arabic astronomy, Albiero was known as “the hen’s beak.” It reffered to the position of the star in the constellation as it marks the beak of the celestial swan. - Albiero, also appeared by the name “beak star” in the Calendarium of the Egyptian astronomer Al Achsasi Al Mouakket, in the 17th century, and was later translated into Latin as Rostrum Gallinae.

When NASA's Curiosity Mars rover landed in 2012, it brought along eclipse glasses. The solar filters on its Mast Camera (Mastcam) allow it to stare directly at the Sun. Over the past few weeks, Curiosity has been putting them to good use by sending back some spectacular imagery of solar eclipses caused by Phobos and Deimos, Mars' two moons. Phobos, which is as wide as 16 miles (26 kilometers) across, was imaged on March 26, 2019 (the 2,359th sol, or Martian day, of Curiosity's mission); Deimos, which is as wide as 10 miles (16 kilometers) across, was photographed on March 17, 2019 (Sol 2350). Phobos doesn't completely cover the Sun, so it would be considered an annular eclipse. Because Deimos is so small compared to the disk of the Sun, scientists would say it's transiting the Sun. In addition to capturing each moon crossing in front of the Sun, one of Curiosity's Navigation Cameras (Navcams) observed the shadow of Phobos on March 25, 2019 (Sol 2358). As the moon's shadow passed over the rover during sunset, it momentarily darkened the light. Solar eclipses have been seen many times by Curiosity and other rovers in the past. Besides being cool - who doesn't love an eclipse? - these events also serve a scientific purpose, helping researchers fine-tune their understanding of each moon's orbit around Mars. Before the Spirit and Opportunity rovers landed in 2004, there was much higher uncertainty in the orbit of each moon, said Mark Lemmon of Texas A&M University, College Station, a co-investigator with Curiosity's Mastcam. The first time one of the rovers tried to image Deimos eclipsing the Sun, they found the moon was 25 miles (40 kilometers) away from where they expected. "More observations over time help pin down the details of each orbit," Lemmon said. "Those orbits change all the time in response to the gravitational pull of Mars, Jupiter or even each Martian moon pulling on the other." These events also help make Mars relatable, Lemmon said: "Eclipses, sunrises and sunsets and weather phenomena all make Mars real to people, as a world both like and unlike what they see outside, not just a subject in a book." To date, there have been eight observations of Deimos eclipsing the Sun from either Spirit, Opportunity or Curiosity; there have been about 40 observations of Phobos. There's still a margin of uncertainty in the orbits of both Martian moons, but that shrinks with every eclipse that's viewed from the Red Planet's surface. NASA's Jet Propulsion Laboratory, a division of Caltech, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover. Malin Space Science Systems, San Diego, built and operates the Mastcam instrument and two other instruments on Curiosity. More information about Curiosity is at: More information about Mars is at: News Media ContactAndrew Good Jet Propulsion Laboratory, Pasadena, Calif.

- NASA’s DART mission will test the feasibility of redirecting an asteroid, but the debris it creates could generate the first-ever manmade meteor shower. - The DART mission includes a spacecraft that will slam into one of the rocks that makes up the binary asteroid Didymos. - A new study suggests we might see some of the debris light up the night sky. - Visit BGR’s homepage for more stories. NASA’s upcoming test of an asteroid redirection system may accidentally trigger the first-ever manmade meteor shower. That’s according to a study published in The Planetary Science Journal that assessed the potential outcomes of the space agency’s upcoming Double Asteroid Redirection Test (DART) mission. The aim of the mission is to test the feasibility that a spacecraft could save Earth from an asteroid impact by slamming into it before it reaches our planet. The mission will send a fast-moving spacecraft to the binary asteroid Didymos, targeting the smaller of the two space rocks while scientists back on Earth observe the results of the impact. This is a big deal, and we may one day have to rely on spacecraft like the one used in the DART mission to push a large, threatening space rock off a collision course with Earth. However, as the authors of the new study explain, the impact itself may disturb enough of the asteroid’s surface debris that it creates an artificial meteor shower here on Earth. The good news is that the researchers say the amount of material flung into space (called ejecta) will be relatively small. It wouldn’t be enough to cause any problems for us here on the surface, but it could be a concern for both uncrewed and crewed spacecraft. “The DART project may also represent the first human-generated meteoroids to reach Earth and is a test case for human activity on asteroids and its eventual contribution to the meteoroid environment and spacecraft impact risk,” the authors write. “This study finds that very little DART-ejected material will reach our planet, and most of that only after thousands of years. But some material ejected at the highest velocities could be delivered to Earth-crossing trajectories almost immediately, though at very low fluxes.” The vast majority of the debris that the DART spacecraft generates will remain with the asteroid thanks to the pull of gravity. A small amount may head to Earth rapidly, and other debris could find its way here many centuries from now. The entirety of the material that reaches Earth will likely burn up in the atmosphere, producing the familiar glow we’ve come to expect from naturally-occurring meteor showers. NASA will be keeping a close eye on how the entire saga unfolds, but it would certainly be a bummer if, in the midst of testing an asteroid defense system, the space agency accidentally flings tiny space rocks at spacecraft already orbiting Earth.

New research led by scientists from the Institute of Geophysics at the Czech Academy of Sciences describes the latest findings of mud on Mars. The team collaborated with researchers from Lancaster University, the Open University, and the Rutherford Appleton Laboratory in the UK, CNRS in France, DLR and Münster University in Germany, and CEED in Norway. Their results are published in Nature Geoscience. Martian mud is a new concept, as previously scientists had not been able to determine whether the lava-like flows were caused by lava or mud. Lionel Wilson, Emeritus Professor of Earth and Planetary Sciences at Lancaster University, said: "We performed experiments in a vacuum chamber to simulate the release of mud on Mars. This is of interest because we see many flow-like features on Mars in spacecraft images, but they have not yet been visited by any of the roving vehicles on the surface and there is some ambiguity about whether they are flows of lava or mud." The team simulated the movement of mud on the landforms that populate the Martian northern lowlands surface. These landforms are thought to be the result of devastating flood events, comparable to the largest floods ever known to have occurred on Earth. In order to conduct simulations on the movement of Martian mud, the researchers used the Mars Chamber at the Open University to recreate the surface temperature (-20°C) and low atmospheric pressure found on Mars. Unsurprisingly, they showed that free-flowing mud under Martian conditions is different from the mud we know and love on Earth. As Eureka Alert explains, this is “because of rapid freezing and the formation of an icy crust. This is because water is not stable and begins to boil and evaporate. The evaporation removes latent heat from the mud, eventually causing it to freeze.” So the mud on Mars comes out looking more similar to what we call "pahoehoe" lava, which we can find on Hawaii or Iceland and forms undulating textures when it cools. Lead author of the study, Dr. Petr Bro, explains the implications of their findings: "We suggest that mud volcanism can explain the formation of some lava-like flow morphologies on Mars and that similar processes may apply to eruptions of mud on icy bodies in the outer Solar System, like on Ceres."

How to Escape a Black Hole Posted on: Feb 1, 2019 Black holes are known for their voracious appetites, binging on matter with such ferocity that not even light can escape once it’s swallowed up. Less understood, though, is how black holes purge energy locked up in their rotation, jetting near-light-speed plasmas into space to opposite sides in one of the most powerful displays in the universe. These jets can extend outward for millions of light years. New simulations led by researchers working at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley combine decades-old theories to provide new insight about the driving mechanisms in the plasma jets that allow them to steal energy from black holes’ powerful gravitational fields and propel it far from their gaping mouths. The simulations could provide a useful comparison for high-resolution observations from the Event Horizon Telescope, an array that is designed to provide the first direct images of the regions where the plasma jets form. The telescope will enable new views of the black hole at the center of our own Milky Way galaxy, as well as detailed views of other supermassive black holes. “How can the energy in a black hole’s rotation be extracted to make jets?” said Kyle Parfrey, who led the work on the simulations while he was an Einstein Postdoctoral Fellow affiliated with the Nuclear Science Division at Berkeley Lab. “This has been a question for a long time.” Now a senior fellow at NASA Goddard Space Flight Center in Maryland, Parfrey is the lead author of a study, published Jan. 23 in Physical Review Letters, that details the simulations research. The simulations, for the first time, unite a theory that explains how electric currents around a black hole twist magnetic fields into forming jets, with a separate theory explaining how particles crossing through a black hole’s point of no return – the event horizon – can appear to a distant observer to carry in negative energy and lower the black hole’s overall rotational energy. It’s like eating a snack that causes you to lose calories rather than gaining them. The black hole actually loses mass as a result of slurping in these “negative-energy” particles. Computer simulations have difficulty in modeling all of the complex physics involved in plasma-jet launching, which must account for the creation of pairs of electrons and positrons, the acceleration mechanism for particles, and the emission of light in the jets. Berkeley Lab has contributed extensively to plasma simulations over its long history. Plasma is a gas-like mixture of charged particles that is the universe’s most common state of matter. Parfrey said he realized that more complex simulations to better describe the jets would require a combination of expertise in plasma physics and the general theory of relativity. “I thought it would be a good time to try to bring these two things together,” he said. Performed at a supercomputing center at NASA Ames Research Center in Mountain View, California, the simulations incorporate new numerical techniques that provide the first model of a collisionless plasma – in which collisions between charged particles do not play a major role – in the presence of a strong gravitational field associated with a black hole. The simulations naturally produce effects known as the Blandford-Znajek mechanism, which describes the twisting magnetic fields that form jets, and a separate Penrose process that describes what happens when negative-energy particles are gulped down by the black hole. The Penrose process, “even though it doesn’t necessarily contribute that much to extracting the black hole’s rotation energy,” Parfrey said, “is possibly directly linked to the electric currents that twist the jets’ magnetic fields.” While more detailed than some earlier models, Parfrey noted that his team’s simulations are still playing catch-up with observations, and are idealized in some ways to simplify the calculations needed to perform the simulations. The team intends to better model the process by which electron-positron pairs are created in the jets in order to study the jets’ plasma distribution and their emission of radiation more realistically for comparison to observations. They also plan to broaden the scope of the simulations to include the flow of infalling matter around the black hole’s event horizon, known as its accretion flow. “We hope to provide a more consistent picture of the whole problem,” he said. Other participants in the research are Alexander Philippov, who was an Einstein Postdoctoral Fellow at UC Berkeley, and Benoit Cerutti, a CNRS researcher at the Université Grenoble Alpes in France. Parfrey and Philippov were members of the Department of Astronomy and Theoretical Astrophysics Center at UC Berkeley, and Philippov is now at the Flatiron Institute in New York. The work was supported by NASA through the Einstein Postdoctoral Fellowships program, CNES, Labex OSUG@2020, NASA’s High-End Computing Program, TGCC, CINES, and the Simons Foundation.

Peter van de Kamp is, to some, a footnote in astronomy today. A trivia question at times. For some early exoplanet hunters, his name was even a bit of a career epitaph — the name you didn’t want to be associated with, so your evidence had better be air tight, or you’ll be another van de Kamp. So who was he? The common view is this: Peter van de Kamp was a Dutch astronomer who thought he’d discovered the first planets outside our solar system. They were just two systems away around Barnard’s Star. But the planets, the source of his life’s work, were simply put, not there. And indeed, time and time again, studies have failed anything like what van de Kamp proposed. His idea was more or less two gas giants, a Jupiter and a Saturn, if you will, around the tiny red star just six light years away, though the number of planets seemed to change. This put them close enough to Earth that the British Interplanetary Society pinpointed the star as the place to visit in their feasibility study on nuclear propulsion known as Project Daedalus. Sure, the Alpha Centauris were closer, but they had no planets to speak of. Read more about great astronomers: In 2018, a very un-van de Kampian world was found there. It was a few times the mass of Earth in a frigid location in its system. It’s closer to Barnard’s Star than Earth is to the Sun, but Barnard’s Star is just 14 per cent the mass of the Sun, so this distance makes it an inhospitable world. Compare that to Proxima Centauri, a little less than two light years closer, which may have a habitable world, and you get a planet, finally, where we’ve long looked for one. But the Barnard’s Star planet isn’t anything like van de Kamp hoped to find, and it is strange and cold and unlikely to have life enough to send an interstellar ship there. But there was something odd in the data too — something maybe the size of Neptune in a long orbit that, oddly, was within about the time span van de Kamp was claiming for his own planets. But the planet, if it exists (right now there’s some strong but inconclusive data) would be just a fraction of the size and would be unlikely to vindicate van de Kamp. Still, his name deserves some esteem. He was a man on the right track. In hindsight, he was just living in the wrong time. Double stars and planet-hunting Peter van de Kamp came to Swarthmore College outside Philadelphia in 1937. Born in the Netherlands in 1901, he was part of a large cadre of Dutch astronomers coming to prominence in the era. Adriaan van Maanen, with a strange dead star to his name, preceded this generation by a few decades, but the other names are familiar to many astronomy fans. Names like Gerard Kuiper, for whom the Kuiper Belt is named, or Jan Oort, whose name describes the realm of the solar system past the Kuiper Belt, the Oort Cloud. Or there was Dirk Reuyl. He was van de Kamp’s cousin. And he, too, tried to claim one of the first planets outside our solar system. But his claims were disproven — by Peter van de Kamp. But let’s back up a little. Peter van de Kamp © Friends Historical Library of Swarthmore College Van de Kamp came to Swarthmore to set about the double star program there. Many stars aren’t alone in the sky. The nearest star system, Alpha Centauri, actually has three stars. Two large stars orbit each other at the centre, while a smaller star, Proxima Centauri, orbits those two stars from a more distant location. Sometimes, when stars orbit other stars (this is called a binary, at least when it’s two stars), both can be easily seen in the sky with a telescope, two points of light that easily resolve. Alpha Centauri A and B are roughly the same size, brightness and mass, so a decent telescope can make out two points of light, even though the stars are “just” 1.7 billion kilometres apart. But other stars aren’t so easily resolved. Sometimes, one star dominates a system. This is the case of Sirius A and B. Sirius A is the brightest star in the night sky. But if you look up, you won’t see Sirius B. At least not without some high grade equipment a bit outside the price range of a common Celestron or Orion under the Christmas tree. That’s because Sirius B is less than 1 per cent the radius of mighty Sirius A. It has this unusual smallness (think: the size of Earth) because it’s the dead remnant of a star like the sun that exhausted its fuel and became a white dwarf. Not only is it less than 1 per cent the radius, it’s less than 1 per cent the luminosity. Read more about science history: So how do you find something the size of Earth around a star twice as big as the sun? Well, Sirius B may be small, but it still has about the same mass as the sun, and Sirius A is only twice as massive. So when you look at Sirius A in the sky, it doesn’t quite sit still like other stars. It deviates a little bit from a centre point. This is because one star doesn’t often cleanly orbit another. They find a mutual point of gravity to orbit in a big tug of war. So in 1844, astronomers figured out that Sirius A didn’t sit still — and thus something invisible pulled on it. By 1862, it had been seen through a telescope. Over 30 years later, a similar invisible companion, Procyon B, was confirmed around the star Procyon A. Peter van de Kamp (centre) and Sproul Observatory staff © Friends Historical Library of Swarthmore College Thus, van de Kamp’s initial searches were for similar invisible companion stars. But there’s a twist to this. It’s not just stars that pull on each other from a common centre of mass. A star and a planet can come to a similar orbital stalemate that pulls one off its centre point in subtle ways. By monitoring a star over time, you might — just might — be able to see it shift in place because of the movements of an invisible companion planet, something van de Kamp became a bit obsessed with. By 1942, he and a protégé, Kaj Strand (a Dane in the midst of the Dutch astronomers of the era) proposed a “substellar companion” around 61 Cygni. Strand was doubling time between Allied military efforts and astronomy work, and there was a strange controversy that came about when someone impersonating a relative of Strand told the New York Times that the duo had named the planet ‘Osiris’. (This was very much so not the case.) This was just as Reuyl, van de Kamp’s cousin, was proposing a planet around 70 Ophiuchi, a star system that had been in the crosshairs of planet hunters since the 19th Century, with frequent claims with limited veracity but no actual success. The most famous case, of one infamous astronomer named Thomas Jefferson Jackson See, was less famous for the scientific strength of the claim than the fact that See, a notorious crank, found himself nearly banned from the Astronomical Journal for how viciously he tried to attack someone who disputed his claims, a recurrent theme in his odious career. 61 Cygni, like 70 Ophiuchi, was a double star system with some seeming discrepancies in the motion of its stars. But the proof laid out by Strand and van de Kamp ultimately held out better than Reuyl and Erik Holberg’s claims. It’s also one of several lost pieces in the exoplanet prehistory — Barnard’s Star wasn’t even the first van de Kamp-related exoplanet claim. It was the third. The second was around Lalande 21185. Sarah Lee Lippincott, another van de Kamp protégé, was a driving force behind it, and was working on the proposed planet there around the same time she drew up the mass estimate and estimated distance of Ross 614B. When the star was found by its own light in 1955 based on her prediction, it was a big success for the Sproul program. By 1963, van de Kamp was making his first official Barnard’s Star projections. Thus, the planet search was always a part of a bigger program to finding invisible companions to stars, a program that — for Sproul — was massively successful, with Ross 614B as one of the bigger crowing successes. That may have been the most unique discovery, but mass estimates made of other systems helped refine the size, mass and other details of many of our closest stellar neighbour. But the problem with the planets lay in the technique. The astrometry problem Astrometry is a term encompassing finding the position of stars, often based on how they move in the sky in relation to each other. On the micro level, it can involve how the stars themselves move. Hence, looking for little changes caused by invisible stars or planets. In the case of Sirius, A and B weren’t that dissimilar in mass. It’s easy to detect a displacement. It’s the same with any star orbiting another (or their common centre of gravity, to get pedantic). But a planet is about one per cent the mass of its star, generously, at the higher end of planetary mass — 13 times the mass of Jupiter or less. The difference this makes in the sky is extremely tiny and hard to detect. In fact, though this is the oldest planet-finding technique, it’s never found a confirmed planet. This was the biggest undoing of van de Kamp. The kinds of changes a planet can make in a star are so small that the slightest bit of observational error can ruin a detection. Sarah Lee Lippincott teaching © Friends Historical Library of Swarthmore College All sorts of reasons float around for the discrepancies at Barnard’s Star — and, as it ends up, so many others, including Epsilon Eridani, another star purported to have a van de Kampian planet. There’s the apocryphal story on the Swarthmore campus of a regional commuter train throwing off the telescope. Flaws in the lens are sometimes blamed. There’s some evidence that the period of the planet corresponds to regular maintenance on the telescope. Little atmospheric blips can make a star appear to move. But any way you cut it, the planets were simply not there. But there are other things to take from it. One is that van de Kamp was a researcher more prescient than the astronomy in-jokes suggest. For instance, he proposed that censuses of regions of the sky could look at several stars at once and figure out which ones were dimmed in their brightness very slightly by a planet crossing in front of them. This proved true with Kepler, NASA’s space telescope that revealed to us thousands of planets. But perhaps most importantly, there was the idea of looking for planets via a wobbling star. Looking for a star moving in place visually has only yielded objects at the small end in between the mass of a planet and the mass of a star, called brown dwarfs. But if you look at the spectra of a star — the breakdown of its light — little changes in the velocity of the star can reveal the movement of planets, in this case, proving that looking for a wobble is the right way to go. The method of looking for changes in the speed of a star has yielded hundreds of planets since its first successful demonstration in 1988 with Gamma Cephei. By 1995, 51 Pegasi b was confirmed, the first bonafide planet around a sun-like star. It took a few years for astronomers to accept it and other new planets were real, partly because of so many errors before. Read more about exoplanets: But now, a little craft called Gaia may vindicate the astrometry technique within the next few years by finding planets via optical changes in its position. A new dataset in the coming years should find planets from space. There are also the flourishes of who he was as a person — gregarious, progressive, popular on campus due to his outsized personality, a close friend and mentor of the rare woman in astronomy Sarah Lee Lippincott, who struggled against greater sexism in academia – that get lost in the dehumanising narrative of his biggest mistake. We are, after all, better than our biggest mistakes, and the esteem van de Kamp left among colleagues was bigger and better than the planets he insisted on. Van de Kamp died in 1995 mere months before the discovery of 51 Pegasi b; 25 years later, his technique may finally bear fruit. But his legacy will remain a continued strange part of the path to planet finding. He may have been wrong — but he was wrong in all the right ways. Had he been born just a few decades later, he might have found the first genuine planets. But as it stands, he aided vastly in our understanding of stars near to us. His legacy is more than his mistakes — it’s part of the fabric of one of the most misunderstood stories in astronomy.

Source: NASA Press Release Images from NASA's Wide-field Infrared Survey Explorer (WISE) reveal an old star in the throes of a fiery outburst and spraying the cosmos with dust. The findings offer a rare, real-timelook at the process by which stars like our sun seed the universe with building blocks for other stars, planets and even life. The star, catalogued as WISE J180956.27-330500.2, was discovered in images taken during the WISE survey in 2010, the most detailed infrared survey to date of the entire celestial sky. It stood out from other objects because it glowed brightly with infrared light. When compared to images taken more than 20 years ago, astronomers found the star was 100 times brighter. "We were not searching specifically for this phenomenon, but because WISE scanned the whole sky, we can find such unique objects," said Poshak Gandhi of the Japan Aerospace Exploration Agency (JAXA), lead author of a new paper to be published in the Astrophysical Journal Letters. Results indicate the star recently exploded with copious amounts of fresh dust, equivalent in mass to our planet Earth. The star is heating the dust and causing it to glow with infrared light. "Observing this period of explosive change while it is actually ongoing is very rare," said co-author Issei Yamamura of JAXA. "These dust eruptions probably occur only once every 10,000 years in the lives of old stars, and they are thought to last less than a few hundred years each time. It's the blink of an eye in cosmological terms." The aging star is in the "red giant" phase of its life. Our own sun will expand into a red giant in about 5 billion years. When a star begins to run out of fuel, it cools and expands. As the star puffs up, it sheds layers of gas that cool and congeal into tiny dust particles. This is one of the main ways dust is recycled in our universe, making its way from older stars to newborn solar systems. The other way, in which the heaviest of elements are made, is through the deathly explosions, or supernovae, of the most massive stars. "It's an intriguing glimpse into the cosmic recycling program," said Bill Danchi, WISE program scientist at NASA Headquarters in Washington. "Evolved stars, which this one appears to be, contribute about 50 percent of the particles that make up humans." Astronomers know of one other star currently pumping out massive amounts of dust. Called Sakurai's Object, this star is farther along in the aging process than the one discovered recently by WISE. After Poshak and his team discovered the unusual, dusty star with WISE, they went back to look for it in previous infrared all-sky surveys. The object was not seen at all by the Infrared Astronomical Satellite (IRAS), which flew in 1983, but shows up brightly in images taken as part of the Two Micron All-Sky Survey (2MASS) in 1998. Poshak and his colleagues calculated the star appears to have brightened dramatically since 1983. The WISE data show the dust has continued to evolve over time, with the star now hidden behind a very thick veil. The team plans to follow up with space and ground-based telescopes to confirm its nature and to better understand how older stars recycle dust back into the cosmos. NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., manages and operates WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode after it scanned the entire sky twice, completing its main objectives. The principal investigator for WISE, Edward Wright, is at the University of California, Los Angeles. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology (Caltech) in Pasadena. Caltech manages JPL for NASA. The IRAS mission was a collaborative effort between NASA (JPL), the Netherlands and the United Kingdom. The 2MASS mission was a joint effort between Caltech, the University of Massachusetts and NASA (JPL). Data are archived at the Infrared Processing and Analysis Center at Caltech. For more information about WISE, visit:

“Researchers at the University of Central Lancashire (UCLan) unveil highest-ever resolution images of the Sun from NASA’s solar sounding rocket mission Newly released images of the Sun have revealed that its outer layer is filled with previously unseen, incredibly fine magnetic threads filled with extremely hot, million-degree plasma. The high-resolution observations have been analysed by researchers at UCLan alongside collaborators from NASA’s Marshall Space Flight Centre (MSFC) and will provide astronomers with a better understanding of how the Sun’s magnetised atmosphere exists, and what it is comprised of. Until now, certain parts of the Sun’s atmosphere had appeared dark or mostly empty, but new images have revealed strands that are around 500km in width - roughly the distance between London and Belfast - with hot electrified gases flowing inside them. The ultra-sharp images were taken by NASA’s High-Resolution Coronal Imager (or Hi-C for short), a unique astronomical telescope carried into space on a sub-orbital rocket flight. The telescope can pick out structures in the Sun’s atmosphere as small as 70km in size, or around 0.01% the size of the Sun, making these the highest resolution images ever taken of the Sun’s atmosphere. The exact physical mechanism that is creating these pervasive hot strands remains unclear, so scientific debate will now focus on why they are formed, and how their presence helps us understand the eruption of solar flares and solar storms that could affect life on Earth. Professor Robert Walsh, professor of solar physics at UCLan and institutional lead for the Hi-C team added: “Until now solar astronomers have effectively been viewing our closest star in ‘standard definition’, whereas the exceptional quality of the data provided by the Hi-C telescope allows us to survey a patch of the Sun in ‘ultra-high definition’ for the first time. “Think of it like this: if you are watching a football match on television in standard definition, the football pitch looks green and uniform. Watch the same game in ultra-HD and the individual blades of grass can jump out at you – and that’s what we’re able to see with the Hi-C images. We are catching sight of the constituent parts that make up the atmosphere of the star.” The international team of researchers are now progressing plans to launch the Hi-C rocket mission once again, this time overlapping their observations with two Sun-observing spacecraft currently gathering further data, NASA’s Parker Solar Probe and ESA’s Solar Orbiter (SolO). Dr Amy Winebarger, Hi-C principal investigator at NASA MSFC stated: “These new Hi-C images give us a remarkable insight into the Sun’s atmosphere. Along with ongoing missions such as Probe and SolO, this fleet of space-based instruments in the near future will reveal the Sun’s dynamic outer layer in a completely new light.” Dr Tom Williams, a postdoctoral researcher at UCLan who worked on the Hi-C data said: “This is a fascinating discovery that could better inform our understanding of the flow of energy through the layers of the Sun and eventually down to Earth itself. This is so important if we are to model and predict the behaviour of our life-giving star.” This research has been published in the Astrophysical Journal.”

A new study suggests that the Giza Pyramids might have been deliberately ‘anchored’ to the pole of the ecliptic at two distinct epochs by making use of certain stars, of religious importance to the Pyramid Builders, found in the circumpolar and non-circumpolar constellations. Such a hypothesis fortifies the possibility that the Pyramid Builders of Egypt were aware of the Precession of the Equinoxes. AWARENESS OF PRECESSION? There has been an ongoing heated debate between researchers in archaeoastronomy and Egyptologists as to whether the ancient pyramid builders of Egypt were aware of the phenomenon known as the precession of the equinoxes. In simple and brief terms, the precession of the equinoxes is the result of a very slow wobble-like gyration of the earth that takes around 26,000 years. The ‘discovery’ of the precession of the equinoxes is attributed to the Alexandrian-Greek astronomer Hipparchus in around 130 BC, and Egyptologists and historians in general totally reject the idea that the Egyptians might have known of the phenomenon thousands of years before. This view was recently voiced again in the international press based on the content of an article in the journal Nature by Dr. Kate Spence, an Egyptologist from Cambridge University . Contrary to popular opinion, the apparent effect of precession is quite noticeable in the sky across a few centuries, as there is considerable change in the position of stars that can be easily picked up by naked-eye observations. Indeed, Philip Morrison of MIT noted that to discover precession requires only a tree (solar gnomon) and faith in the veracity of one’s grandfather (an oral record). Thus over the 700 years or so that led from the formation of the ancient Egyptian civilisation in c. 3200 BC to the start of the 4th Dynasty in c. 2500 BC, the rising place (known in astronomy as the azimuth) of stars such as, say, those in Orion’s belt, would have changed by as much as 3° on the horizon, and as much as 2.5° at culmination on the meridian. This alone has led many modern researchers to remark that it would have been unlikely for a people like the ancient Egyptians, who were very keen and avid observers of the sky and stars, not to be aware of the precessional shift, even though they might not have understood its underlying cause or have been able to compute it mathematically . In 1894 the British astronomer, Sir Norman Lockyer (1836-1920), the ‘father of archaeoastronomy’, brought further evidence in support of this view, in his book The Dawn of Astronomy (1894), when he demonstrated that the ancient Egyptians’ aligned their temples to stars rising in the east and often changed the alignment of the temple in order to take into account the drift caused by precession. Athough Lockyer was largely ignored by the Egyptologists, a century later the same findings were reported by the American astronomer R.A. Wells for temples such as the Satet temple of Isis on Elephantine Island in Upper Egypt . It was not until 1964 that Lockyer’s findings prompt the well-known MIT professor Giorgio de Santillana to conclude that: “When a stellar temple is oriented so accurately that it requires several reconstructions at intervals of a few centuries, which involved each time the rebuilding of its narrow alignment on a star, and the wrecking of the main symmetry that goes with it; when Zodiacs, like that of Denderah, are deliberately depicted in the appearance they would have had centuries before, as if to date the changes, then it is not reasonable to suppose the Egyptians were unaware of the precession of the equinoxes, even if their mathematics was unable to predict it numerically. Lockyer let the facts speak for themselves, but it is he who has given the proof. Actually, the Egyptians do describe the Precession, but in a language usually written off as mythological or religious.” There are several astronomers who are open to the idea that the ancient Egyptians knew of precession , but as far as I can tell, the only Egyptologist who openly supports Santillana’s view is the American scholar Jane B. Sellers . The rest either choose to ignore it or attempt to disprove and discredit this idea at every opportunity . It is well-known that my colleague Graham Hancock and I fully endorse Santillana’s views, and that we have also argued that the pyramid builders of Giza not only were aware of Precession but also incorporated its principles in their architecture for religious and ritual purposes . In this present article I will review another aspect of the Old Kingdom pyramids which also demonstrates this fact, but from a totally different and new viewpoint. - Nature, Volume 408, 16 November 2000 pp. 230-4 - See for example Jane B. Sellers, The Death of Gods in Ancient Egypt, Penguin 1992, p. 9. - R.A. Wells, Sothis and the Satet Temple on Elephantine: A direct Connection, SAK 12, 1985; also BSAK 4, 1990 - Preface to the 1964 edition of The Dawn of Astronomy, M.I.T. Press 1964. - Op.cit. J. B. Sellers - Dr. Kate Spence, an Egyptologist from Cambridge University, remarked on several occasions recently to the British media that the ancient Egyptians were poor astronomers who could not have known of Precession (“They did not have a precise grasp of astronomy” Daily Mail 16.11.2000 p. 16; “Great Builders; No clue about Astronomy: Their building expertise is beyond doubt”, but Spence said her findings show they were poor astronomers. “This does show they did not have a sophisticated observation of astronomy.” London Reuter 16.11.2000) - The Orion Mystery, Heinemann 1994; Keeper of Genesis, Heinemann 1996 THE POLE OF THE ECLIPTIC The Earth tilts some 23° 26′ from the plane of the ecliptic. This angle, however, changes fractionally in cycles of 40,000 years from a minimum of about 22° 6′ to a maximum of about 24° 30′ due to a phenomenon known as the obliquity of the ecliptic. Calculations show that the angle of tilt has been steadily decreasing since the beginning of recorded history, c.3500 BC, at the average rate of about 40″ per century. Using the accepted rigid formula , it can be shown that in c. 2500 BC, when the construction of the Giza pyramids began, the tilt of the earth’s axis was 23° 58′. The Giza pyramid site is at latitude of 29° 59′, which means that the north celestial pole of the sky was at an altitude of 29° 59′. We always think in terms of the north celestial pole as being the focal point of the sky, an immovable imaginary point around which all the fixed stars seems to revolve in concentric circles. So entrenched is this idea that we ignore or are unaware that this imaginary point is not the true focal point of the sky at all. And even though the idea that the north celestial pole is a fixed point holds true for a short a very period of time, the statement becomes invalid over long periods of time because of precession. The fact is that the north celestial pole drifts away from the fixed field of stars at the rate of about 20″ arcseconds a year due to the perpetual wobble-like cycle of our planet. Furthermore the north celestial pole will keep on drifting from the fixed star field up to a full 47° (about one quarter of the visible sky field) over its 26,000 years cycle. This is hardly a fixed point in terms of cosmic time. There is, however, another point in the sky which drifts away from the fixed star field at the very much slower rate of 0.4 arcseconds per year, that is 50 times slower than the drift of the north celestial pole and thus, by true definition, making it the real focal point of the sky. This point is known as pole of the ecliptic. Furthermore the pole of the ecliptic will only displace itself a mere 2.5° over its 40,000 years cycle. The pole of the ecliptic is located in the heart of the constellation of Draco, approximately between the stars Zeta Draco and Al Tais. Assuming that the ancient astronomer-priests of Egypt began observing and recording the position of stars some 200 years before the dynastic period, say c. 3500 BC, up to the start of the 4th Dynasty in c.2500 BC, a simple calculations show that the position of the pole of the ecliptic would have displaced itself by only 6 minutes of arc (0.1°), over this whole 1000 year period. On the other hand the north celestial pole would have been displaced by 333 minutes of arc (5.55°). Imagine a dartboard where one dart (the pole of the ecliptic) is 1 cm away from the bull’s eye and another (north celestial pole) is 50 cm away, and you will get the picture. The pole of the ecliptic will cross the meridian twice each day i.e. upper and lower culmination. Calculations show that during the Pyramid Age, and as seen from the latitude of Giza (29° 59′), the pole of the ecliptic would have had its upper culmination at the meridian at an altitude of 53° 57′ (29° 59′ + 23° 58′) . The table below shows the altitude of the pole of the ecliptic at upper culmination at the meridian at different latitudes/locations in Lower and Middle Egypt, roughly encompassing the region of pyramid building during the Old Kingdom: |Location||Latitude||Upper culmination of Pole of the Ecliptic| |Abu Ruwash||30° 02′||54° 00′| |Giza||29° 59′||53° 57′| |Dashur||29° 45′||53° 43′| |Wadi Sannur||29° 00′||52° 58′| |Beni Hassan||28° 00′||51° 58′| |El Amarna||27° 30′||51° 28′| |Altitude at upper culmination of the pole of the ecliptic From difference location in Egypt. The angle of upper culmination of the pole of the ecliptic thus varied +/-2° from 52° depending where you stood in the desert region from Abu Ruwash to El Amarna. THE POLE-SPEAR OF THE HAWK-HEADED HORUS The pole of the ecliptic seems to have been known by some ancient cultures. For example, the French astronomer A. Bouche-Leclerq noted that “it is well-known that the pole par excellence for the Chaldeans was the pole of the ecliptic, which is in the constellation of the Dragon (Draco)” . Also the MIT scholar Giorgio de Santillana believed that the ancients perceived the pole of the ecliptic as the centre of a ‘whirlpool’ in the sky . In keeping with this hypothesis, R.A. Schwaller de Lubicz demonstrates that the astronomical arrangements of the circumpolar and zodiacal constellations at the centre of the circular Denderah Zodiac show both the pole of the ecliptic as well as the north celestial pole. As the author and pyramid researcher Peter Tompkins explained: “The zodiac (of Denderah) is a circle at the centre of which is our north pole… our north pole is correctly located in the constellation of the jackal, or Little Bear (Ursa Minor), as it was at the time the zodiac was carved, sometime about the first century BC. But the zodiac also shows the pole of the ecliptic, located in the breast of the hippopotamus, or constellation of Draco. To Schwaller this explains the spiral formation of the constellations. The mythological figures are entwined in two circles –one around the north pole and one around the pole of the ecliptic. Where these two circles intersect marks the point of the equinox, or due east. The zodiac thus becomes a calendar going back to remote antiquity.” In the 1970s the professor of the History of Science, Livio C. Stecchini, examined ancient Egyptian charts of the circumpolar constellations, showing the Hippopotamus (Draco) and the Thigh (Ursa Major or Great Bear) as well as a hawk-headed man, probably Horus, seen pointing a pole or spear at the head of the Bull . According to the Czechoslovakian Egyptologist Zybnek Zaba, the pole or spear held by the hawk-headed man indicated the meridian line passing through the north celestial pole. But Stecchini did not agree. He maintained that Zaba did not notice that the spear’s head divided the seven stars of the Thigh (Big Bear) constellation into groups of three and four stars. This line defined by the spear, argued Stecchini, does not indicate the meridian passing through the north celestial pole at all but the meridian passing through the pole of the ecliptic. According to Stecchini, the ancient Egyptians not only understood the precession of the equinoxes but also knew that the true meridian is the one passing through the pole of the ecliptic. Another point that seems to have escaped both Zaba and Stecchini, however, is the peculiar way the standing Hippopotamus holds a rope with its right hand that is attached to the lower end of the Thigh constellation. In my opinion the position of the ‘right hand’ seems very much to denote the actual position of the pole of the ecliptic onto which the Thigh (Great Bear) constellation seems to be ‘moored’ to or ‘anchored’ with a rope. - See Appendices 1 and 2 in The Orion Mystery. - L’Astrologie Grecque, Paris 1899 reprinted 1963; also Hamlet’s Mill, D.R. Godine Publishers, Boston 1969, p.143, fn. 11. - Hamlet’s Mill, p.239. - Peter Tompkins, Secrets of the Pyramid, Allen Lane, London 1973, p. 172-3. - Ibid. p.174. THE GREAT MOORING-POST OF THE SKY There are many references to a mysterious object called the ‘Great Mooring-post’ in the Pyramid Texts, often found alongside passages that are clearly astronomical in character . “The Great Mooring post calls to you… you ascend here as a star, the Morning Star. He comes to you his father, he comes to you, O Geb; take his hand and let him sit on the great throne that he may join the two ‘Hrmt’ [?] of the sky. ” PT 2014 “The doors of the sky are open for you, the mourning-woman summons you as Isis, the Great Mooring-post calls to you as Nephtys, you have appeared upon the causeway…” PT 2232 It is clear that the ‘Great Mooring-post’ is somehow to be regarded as being associated to the sky ascent of Osiris, the form of the defunct king who is assisted by his sisters, Isis and Nephtys. Now it is well-known that Osiris in his stellar form is the constellation of Orion. Not surprisingly, therefore, there are other references in the Pyramid Texts to the Great Mooring-post which appear in passages where Orion is specifically mentioned. For example: “O King, you are this great star, the companion of Orion, who traverses the sky with Orion, who navigates the Netherworld with Osiris… the Great Mooring-post cries out to you as to Osiris in his suffering.” PT 882-4 The Great Mooring-post calls out, because you are he who stands and will never tire in the midst of Abydos [Osiris?]… Betake yourself to the waterway, fare upstream to the Thinite Nome, travel about Abydos, in this spirit form of yours which the gods commanded belongs to you, may a stairway to the netherworld be set up for you to the place where Orion is…” PT 1711-7 Orion, however, is not a circumpolar or even a northern constellation but very much a southern constellation. Oddly, there are other passages which associate the Great Mooring-post to the ‘imperishable stars’, the northern circumpolar stars that never ‘die’ i.e. never set : “The doors of the sky are opened for you, the doors of the firmament are thrown open for you… the Mooring-post cries to you, the sun-folk call you, the Imperishable Stars wait on you…” PT 876 “The Great Mooring-post calls to you… may you remove yourself upon your iron throne, may you cross the lake, may your face be [cleansed?] in the north of the sky…” PT 1012-6 It has long been accepted by Egyptologists that the imagined skyward ascent of the king’s soul was either in the north of the sky among the ‘Imperishable Stars’ or in the south of the sky amongst the stars of Orion . This specific belief is materialised in the Great Pyramid of Giza by the so-called star-shafts emanating from the King’s Chamber, where one was targeted north to the circumpolar stars and the other targeted south to Orion . In consideration of this, it is justified to wonder if the pyramids were not, in some symbolic way, ‘moored’ or ‘anchored’ not just to the circumpolar region of the sky in general but, more specifically, to the pole of the ecliptic, the true ‘pole’ of the sky ? - See PT 794; 863; 872;884;1012; 1366; 1711; 2013; 2232; 2239]. - R.O. Faulkner, The King and the Star-Religion in the Pyramid Texts, J.N.E.S. xxv, 1966, pp.153-161. - I.E.S. Edwards, The Pyramids of Egypt, Penguin, London 1993, p. 285. - E.C. Krupp, Echoes of the Ancient Skies, Oxford Univ. Press, 1983, p.102. THE SLOPE OF THE PYRAMIDS It is well known that the monumental Pyramids of the Old Kingdom in Egypt, from the 4th Dynasty (c. 2500 BC) to the 6th Dynasty (c.2100 BC), have slopes 52° +- 2°, with two notable exceptions being the two pyramids at Dashur, with the Red Pyramid having a slope of about 43° 22′ and the Bent Pyramid having half its height at slope of 54° 27′ and the top half at 43° 22′. Today there are still some 25 royal pyramids standing in the 25 kilometres strip of desert land adjacent to the west bank of the Nile Valley near modern Cairo. Most have their core masonry sufficiently intact to allow relatively accurate measurements of their slopes. A recent batch of slope measurements were provided by Jaromir Malek and John Baines in 1984 and Mark Lehner in 1997, of which 17 pyramids spanning from the 4th to the 6th Dynasties can by analysed. The first, a pyramid attributed to the relatively unknown pharaoh Huni of the 3rd Dynasty, is generally thought to have been ‘converted’ into a true, smooth-sloped pyramid by the founder of the 4th Dynasty, king Snefru, the father of the Khufu builder of the Great Pyramid at Giza. I have thus considered the Meidum pyramid as being part of the 4th Dynasty trend. |PHARAOH||Dynasty||Location||Slopes (Malek & Baines)||Lehner| |Huni||3||Meidum||51° 50′ 35″||51° 50′ 35″| |Snefru||4||Dashur North||43° 22′ 00″||43° 22′ 00″| |Snefru||4||Dashur South||54° 27′ 44″||54° 27′ 44″| |Khufu||4||Giza||51° 50′ 35″||51° 50′ 40″| |Djedefre||4||Abu Ruwash||60° ~||52° ~| |Khafre||4||Giza||53° 07′ 48″||53° 10′ 00″| |Menkaure||4||Giza||51° 20′ 25″||51° 20′ 25″| |Userkaf||5||Saqqara||53° 07′ 48″||53° 07′ 48″| |Sahure||5||Abusir||50° 11′ 40″||50 11′ 40″| |Neferirkare||5||Abusir||53° 07′ 48″||53° 07′ 48″| |Niussere||5||Abusir||51° 50′ 35″||51° 50′ 35″| |Isezi||5||Saqqara South||53° 07′ 48″||52° 00′ 00″| |Unas||5||Saqqara||56° 18′ 35″||56° 18′ 35″| |Teti||6||Saqqara||53° 07 48″||53° 07′ 48″| |Pepi I||6||Saqqara||53° 07 48″||53° 07′ 48″| |Merenre||6||Saqqara||53° 07 48″||53° 07′ 48″| |Pepi II||6||Saqqara||53° 07′ 48″||53° 07′ 48″| |Source: Atlas of Ancient Egypt by Jaromir Malek and John Baines (Adromeda Oxford 1984) and The Complete Pyramid by Mark Lehner (Thames and Hudson 1997).| No convincing explanation has, so far, been given as to why the Pyramid builders selected slopes of 52° +/- 2°. There are geometrical theories and also construction issues that have been proposed as an explanation in recent years, but none are very satisfactory. From table 1 we can see that the angle of slope most often encountered is 53° 07′ 48″, which occurs in nearly 50% of the Old Kingdom pyramids. This range of angles, from 54.5° to 51.7°, as can be seen from Table 1 above, bears a conspicuous correlation to the range of angles of the pole of the ecliptic of 54.5° to 51.5° at upper culmination as seen from across the pyramid fields of the Old Kingdom. In consideration of this, it is very tempting to inquire whether the ancient builders could have incorporated the angle of the pole of the ecliptic in their design of pyramids. Let us examine this possibility. A STAR RELIGION There are many studies that show that the pyramid builders linked their religion, and consequently their pyramids, to the stars . It is also known that the ancient pyramid builders observed the stars as they culminated at the meridian north and south. Special attention, too, was given to the rising of the stars in the east, especially at dawn. The dominant group of stars that have been identified from ancient Egyptian sources with certainty are Orion, Sirius and the circumpolar constellations of Draco, Ursa Major and Ursa Minor. These circumpolar stars were perceived as being ‘immortal’ and ‘indestructible’ because they never rise or set but perpetually revolve in concentric circles around the north celestial pole. This led many Egyptologists to assert that the ancient Egyptians gave special attention to this region of the sky. At the very least, this all shows that the pyramid builders were avid observers of the rising and culmination of the stars, and most probably recorded their positions over long periods of time. It is also reasonable to assume that observations of the circumpolar stars might have been made while also observing simultaneously other stars rising in the east and still others simultaneously culminating in the south. The opinion is unanimous among Egyptologists and astronomers that the square bases of the Old Kingdom pyramids were deliberately made to face the four cardinal directions, in some cases with remarkably high precision. This, when coupled with the ancient builders’ keen interest in the sky, would mean that the dominant alignments were an axis running east-west and another axis running north-south, forming an imaginary cross through the pyramid. The implications are, therefore, that the east-west axis served for the observation of the rising of celestial bodies in the east whereas the north-south axis served for the observation of the culmination of celestial bodies north and south at the meridian. Now, due-east defines the rising place of the equinoxes i.e. the positions occupied by the sun at the spring or autumn equinox. When an equinox is rising due-east on the horizon, the prime meridian or ‘great circle’ will loop directly above, passing through the north celestial pole and also through the pole of the ecliptic. Thus, by definition, the pole of the ecliptic is always on the prime meridian line when an equinox point is rising in the eastern horizon. However, the pole of the ecliptic will be at upper culmination at the meridian (about 53.5° altitude) only when the vernal point (spring equinox) is rising due-east. When this happens, all the main ‘stations’ (or ‘collures’) of the sky –the two equinoxes and the two solstices– will be found in the four cardinal directions of the celestial landscape. Thus if the ancient pyramid builders had wished to design a symbolic representation of this very special moment in time when the sky can be truly said to be in perfect order around the pole of the ecliptic, they would have selected a time when Orion was sitting due-south at the same time as the pole of the ecliptic was sitting due-north and the vernal point was sitting due-east. When was that time? DEFINING THE ‘BEGINNING’ AND COSMIC ORDER OF THE WORLD By using astronomical software to scan the epochs, we find, interestingly, that the only one time in human history when this arrangement could have happened was c. 10,500 BC. Even more interestingly is the fact that the architectural simulacra defined by the Giza necropolis appears to ‘freeze’ that moment in immutable stone monuments: - The central pyramid, with its slope of 53 07′ 48′ is less than 1 degree away from the upper culmination of the pole of the ecliptic. - The three pyramids are set along the north-south ‘collure’ i.e. along the prime meridian of the sky. - The general pattern of the three pyramids correlates with the general pattern of the three central stars of Orion i.e. Orion’s belt. - The vernal point is in alignment with the Great Sphinx as well as the constellation of Leo. This astronomical conjunction, which only occurs in c. 10,500 BC, does not, of course, mean that the monuments themselves were constructed in that remote epoch. What it does is suggest that the ancient pyramid builders of Giza wanted to define the ‘beginning’ and the cosmic order of the world in a grandiose architectural symbolic plan. It also adds more cogency to the argument that the ancient Egyptians not only observed and recorded the stars over vast periods of time, but that they were well-aware of the effects of Precession.

NASA's Mission to Pluto and the Kuiper Belt October 22, 2019 University of Colorado "Pluto at perihelion party" flyer. (Courtesy of Fran Bagenal) New Horizons and its seven scientific instruments are healthy and performing well. As our spacecraft plows ever deeper into the Kuiper Belt – billions of miles from home – we continue to collect many kinds of new data. But before I say more about that, I want to reflect a little. Precisely 30 years ago last month, in September 1989, Pluto passed its perihelion, which means it passed as close to the Sun as it ever gets. While perihelion is still almost 3 billion (!) miles away, it still represented the easiest time to reach Pluto. After all, its farthest point from the Sun is almost 5 billion miles away! Back in 1989, the Pluto science community celebrated the perihelion passage with parties (like the one whose flyer is shown here) and hoped for a future mission to explore this distant planet. In those intervening 30 years we prevailed to see a mission to explore Pluto funded, designed, launched and flown across the solar system. That mission went through many iterations but ultimately came to be known as New Horizons. The result of New Horizons' brief but powerful flyby is that we now know more about Pluto after its initial exploration that we did about any other planet when it was first explored. We know so much, in fact, that we long for a follow-up orbiter to answer the many questions and quandaries that New Horizons raised by becoming the first mission there. But I digress; the subject of if and when we fly a follow-up orbiter mission to Pluto is a subject for the next Planetary Decadal Survey. What I want to tell you about next is what has been taking place on New Horizons since I last wrote, and what is immediately ahead. Most of our current operations involve the continued downlink of 2014 MU69 flyby data to Earth, which will go on for at least another year. But we're also taking new data at a fast clip. Last month we observed a variety of Kuiper Belt objects (KBOs) and dwarf planets in the distance for comparison to both MU69 and Pluto. Our view of Pluto has expanded since 1989 from a distant point of light to a planet we now know to be a scientific wonderland. See the online version of this map at nationalgeographic.com (Credit: National Geographic) We also conducted a thorough calibration campaign of all seven scientific instruments, so that we can make the most of the observations of MU69 and more distant worlds. This was the first complete instrument calibration campaign on New Horizons since shortly after the Pluto flyby. These complex calibrations, which our team designed, built and then tested for months before they were carried out, performed flawlessly. They will be transmitted to Earth over the next year, along with the remaining MU69 data and new Kuiper Belt science observations. Another important activity was the upload of new, more capable software to the Long Range Reconnaissance Imager (LORRI), the telescopic CCD camera aboard New Horizons. This upgrade allows LORRI to take longer exposures and detect fainter science targets than ever before. We transmitted the software in July and tested it – successfully -- in early September. Starting in December, when we next make KBO observations, this new capability will be in regular use for KBO exploration! There's a lot of activity on the science front too. First up are continued, essentially 24/7, plasma and dust observations of the outer heliosphere in the Kuiper Belt. These unique measurements improve on what the Voyagers collected when they traversed the same distances from the Sun in the 1990s and 2000s, because the instruments aboard New Horizons were built so much later and are therefore much more capable than their Voyager counterparts. But in addition, the New Horizons plasma and dust observations teach us about how that environment modifies the surfaces of KBOs and dwarf planets – adding to the storehouse of knowledge about the worlds in the solar system's third zone, the Kuiper Belt. We also just this month delivered a new set of MU69 flyby and other data to the open-source NASA Planetary Data System, or PDS. After peer review, the PDS will release these New Horizons data for anyone in the word to access! And we also recently had a new suite of Pluto surface feature names approved. Key individuals and missions that paved the way for the historic exploration of Pluto and the Kuiper Belt were honored in these 14 Pluto feature names. Read more about the names here and see the map below. Newly named official features on the map of Pluto. (Credit: NASA/Johns Hopkins Applied Physics Laboratory/Southwest Research Institute/Ross Beyer) Coming next? As alluded to, in December we plan on making some distant KBO observations we didn't even know were possible until September. We'll get a relatively close look at one KBO (though it will still be just a point of light), and we'll observe another at a different viewing geometry to see how its surface scatters light – and give us insight into surface properties like its porosity and roughness. And if that wasn't enough, our science team reported dozens of new results at last month's Division for Planetary Sciences meeting, and we and the broader scientific community are preparing to submit almost 20 new research papers on Pluto and MU69 to the planetary science journal Icarus. And that's my report for now. I plan to write again in a few months. Meanwhile, I hope you'll keep on exploring — just as we do! There are many ways to follow New Horizons news and commentary on social media! You can find others by searching on the Web.

The world’s second black hole photo announced! Can high-definition images reveal the mystery of quasars? After a long study of a black hole in April 2017, astronomers from more than 30 research institutes around the world have finally finished filming this black hole. In April 2019, the first photograph of a black hole was declared an important milestone in the study of black holes. A year later, astronomers released the world’s second photograph of a black hole. A photograph of the central core of the quasar 3C 279 and its reactive origin. It was taken in April 2017 at a distance of 5.5 billion light-years. On April 7, 2020, local time, the corresponding research results were published in the journal Astronomy & Astrophysics. The Research was published under the title “Visualization with the Event Horizon telescope” of the archetypal blazar 3C 279 with a maximum resolution of 20 microseconds. Mysterious heavenly body Presumably, everyone has heard of black holes. In 1915, Einstein completed the foundation of his general theory of relativity and officially published. The general theory of relativity predicts that in outer space there is a celestial body that is caused by the gravitational collapse of a sufficiently large star after the fuel of the nuclear fusion reaction is exhausted and dies. The density of this celestial body is extremely high, the body is actively low, and gravity is also extremely strong. So strong that even light is attracted and cannot escape. In 1916, the German physicist Karl Schwarzschild made an exact solution for this prediction. Karl Schwarzschild calculated a vacuum solution of the Einstein field equation, which shows that if the actual radius of the static spherically symmetric star is less than a fixed value (this is a certain value – the famous Schwarzschild radius), and around strange phenomena will occur to him: as soon as you enter the interface called “Vision”, even the light cannot exist. It was not until 1969 that American astrophysicist John Archibald Wheeler first proposed the concept of a “black hole” and has since spread the world. In 1970, the American Freedom satellite discovered Cygnus X-1, which is different from other sources of rays. Cygnus X-1 has a huge blue planet, 30 times heavier than the Sun. An invisible object, heavy as the sun, pulls. Astronomers agreed that this object was a black hole, which was also the first black hole in the history of human discoveries. In general, the study of black holes by scientists is very difficult. Most of the reason is that black holes cannot be observed directly. So scientists can only learn about their existence Lei learned that before an object is inhaled by a black hole, the acceleration caused by the gravity of the black hole will cause friction. Which will release the “information about the edges” of X-rays and gamma rays. And this is the evidence that scientists have received for the black hole. Of course, by indirectly observing the trajectory of stars or interstellar clouds.

Dark matter is kind of old-hat in these exciting days of dark energy. Nevertheless, we don't know very much about it. We know that it exists, we have a very good idea of where it is, and we even know how much of it is around—but we don't know what it is or how it interacts with other matter aside from via gravity. These are now central questions for those who study dark matter, but they are also expected to be a short-lived ones. We can expect some pretty good answers in the next ten years as the LHC begins to build up a large database of collisions and data comes in from many cosmological observations that are already in progress. The cosmological observations are already raising eyebrows and causing theorists to sharpen their pencils, though. All of these observations find significantly more electrons and positrons than expected coming from the galactic center. Now, in a very cool piece of physics, researchers have shown that all of these observations can be explained by dark matter interacting with itself. First, lets take a look at the observational data, starting with the cosmic microwave background radiation. The current map, produced by WMAP, shows a haze of hard radiation around the galactic center. It turns out that the data is best explained by synchrotron radiation, produced by charged particles going around in circles near the galactic center. But that implies that there are more charged particles out there than we'd expect. Then there is the data obtained by PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics). The scientists in charge have found that there are many more high-energy electrons and positrons than can be accounted for by the interaction of high-energy cosmic rays with the interstellar medium—they have already accounted for all other known sources in order to study cosmic rays in the first place. Similar results have been found by other cosmic ray observatories, and by gamma ray observatories as well. There are other observations that seem to display the same sort of anomaly but—and here is the kicker—all of these experiments are observing different physical phenomena in different ways, yet reporting the same problematic result. To add to cosmologists' problems, the conflicting results have been obtained by the LIBRA/DAMA collaboration and their competitors. LIBRA/DAMA claims to have observed an annual modulation in dark matter collisional interactions, a result they ascribe to the Earth traveling with and against galactic rotation as it circles the sun. Similar experiments run by other groups have failed to find such a signal, and the contradictory results have, frankly, confused everyone. To make matters worse, every single observation could be explained by assuming that something is unusual about that particular observation—for instance, supernovae could be blurring WMAP's vision. But this is pretty unsatisfactory, because the point of observation is to collect phenomena under an umbrella of a few descriptive and predictive models, rather than adding extra phenomena to explain each observation. A group of scientists have taken the first steps toward attempting to unify these phenomena under a single theoretical umbrella. To do this, they have posited that the electrons and positrons are the result of dark matter annihilations, while other annihilation paths that lead to different particles are suppressed. This idea is not as obvious as it sounds, because the number and energies of the electrons and positrons indicate that dark matter must be pretty strongly interacting, and interacting is on the list of things dark matter doesn't do. This problem can be alleviated if one assumes that there is relatively long-range force that acts between dark matter particles. This force can then enhance the probability that dark matter annihilates in a way that produces electrons and positrons while also suppressing other annihilation pathways. The nice thing is that this force provides an internal structure to dark matter that also explains why DAMA/LIBRA saw a dark matter annual modulation signal and other experiments did not. In other words, this single hypothesis brings a wide range of observations together and makes predictions about the properties of dark matter—everything you want in a hypothesis looking to make its way to theory status. But, I hear you say, they have replaced a few special phenomena that we know exist with one force that we don't know exists—surely, that is a step backwards. Well, it is true that further examination may prove that some of the observations are the result of special circumstances. It is, however, unlikely that all of them are. Furthermore, we know that there are very likely to be other bosons out there, awaiting the LHC attempt to reveal their existence. It doesn't seem unreasonable to suppose that one of them has the mass required for a dark force carrier. So, no, this isn't pure speculation, and, no, it doesn't rely on "something really strange emerging from the LHC." Nevertheless, it still requires a lot of confirmation before it gets its own chapter in physics text books. Physical Review D, DOI: 10.1103/PhysRevD.79.015014

As we all know, the moon landings started 50 years ago this July, and over the course of six subsequent visits, astronauts brought back 842 pounds of lunar rocks, pebbles, and soil. Believe it or not, that little collection changed our understanding of where we came from. Moon rocks tell the story of creation How? Well, around 4.5 billion years ago, when the solar system was still in its infancy, it was a much more chaotic place. The sun had burst into being, and it was still surrounded by bits of cosmic debris, all smashing into one another and clumping together to form the planets. Around this time, it is believed, the proto-Earth is thought to have been hit by a Mars sized planet. The resulting cataclysm fused the two worlds together, forming our Earth. (see pic sequence below). The power of that collision ejected material from both bodies, which eventually accreted together to establish the Earth/Moon system. It goes without saying the early moon was covered in an ocean of magma, which settled and cooled into the form we know today. Scientists are still debating the details of this hypothesis. However, because the Earth and moon are made out of similar base materials – suggesting they were created from the same source material – and because that material was molten at the time they formed, it seems reasonable to assume this is due to the power of the theorized impact. Even so, that’s only the beginning of the story. What can moon craters tell us about the history of the solar system? A huge part of the history of the lunar crust is its craters. And scientists have been able to use the Apollo samples to accurately date those craters. The moon has changed far less than the Earth, but that doesn’t mean it hasn’t changed at all. Asteroids have hit it over and over again, leading to the pockmarked surface we can see in the night sky. Those craters tell the story of what happened in the solar system after the Earth and the moon were formed. By age-dating the moon’s craters, we can age-date craters elsewhere. The bigger the craters, the longer ago they were made – basically, because bigger chunks of debris were much more common further back in time – meaning we have an accurate impact history of the solar system right on our doorstep. And it doesn’t stop there. Learning how old the moon’s craters are led to another stunning hypothesis: that the outermost planets — Jupiter, Saturn, Uranus, Neptune — have changed their orbits over their lifetimes. The craters show that around 600 million years after the planets formed, there was a second period of heavy bombardment, meaning that the moon got pounded by a lot of asteroids. This was odd, as the frantic pace of asteroid collisions were thought to have settled down by then. So what explains the additional pummeling during this time? Although scientists aren’t sure, one possible idea is that those big gas giant planets moved closer to the sun to begin with and then spun farther away, disturbing the “settled” field we see around us today. So what does this mean now? The White House is currently pushing NASA to send humans to the moon again by 2024. For now, the plan is for those astronauts to visit the lunar south pole at a crater called the South Pole–Aitken Basin — one of the biggest, deepest, and therefore oldest of the moon’s craters. It’s possible the impact that created the basin was so powerful that it exposed the mantle, or interior, of the moon. Take a look at the color picture of the size of the basis to get an idea why scientists are so excited. It’s over 1,300 miles across. And, because we can’t directly study the Earth’s mantle in the way scientists would like, this is the next best thing. After all, it’s thought to have originated from the same base material at the same time. Even better, it should help us understand why the Earth has such active geology while the moon doesn’t. And that knowledge could have a lot of practical implications. For instance, in the future, if humans want to start mining asteroids for metals and minerals, it will be enormously helpful to know the exact geologic makeup of a particular asteroid before we arrive. Practicing on the Moon first will help us refine the skills we need to get it right when we’re further from home. Yes, there are a lot of reasons for us to return to the moon and establish a more permanent presence there. The moon would be an excellent crucible laboratory to teach astronauts how to better survive long, lonely missions in deep space; it would serve as a launching ground for missions to Mars, or beyond; and it could even serve as a new source for the mining of natural resources as we run ever shorter here. We’ve got a lot to look forward to. . . I just wonder what the next 50 years will bring?

Basic Helium Facts Atomic Number: 2 Element Symbol: He Element Family: Noble Gas Atomic Mass: 4.002602(2) Electron Configuration: 1s2 Discovery: First identified: Pierre Janssen in 1868. First Isolated: Sir William Ramsay in 1895. Janssen was a French astronomer who observed a new yellow spectral line while observing a total solar eclipse in 1868. He assumed it was part of the sodium spectrum. English astronomer Norman Lockyer later observed the same line but could not link it to sodium. Together with English chemist Edward Frankland, they decided it was associated with a new element. In 1985, Scottish chemist William Ramsay isolated a gas from a sample of a mineral cleveite which contained the yellow spectral line. Swedish chemists Per Teodor Cleve and Abraham Langlet independently made the same discovery the same year in Sweden. Name Origin: Helios, Greek god of the Sun. Lockyer and Frankland named their unknown element after the location it was first discovered, the Sun. Helium-3 is a stable isotope of helium containing 2 protons and 1 neutron. He-3 accounts for 1.37 x 10-4% of helium found in the atmosphere Helium-4 is also stable with 2 protons and 2 neutrons. It is the most common form of helium found. It’s abundance in the atmosphere is 99.999863% of all helium found. Density: 0.000164 g/cm3 Melting Point: 0.95K (-272.20 ºC or -457.96 ºF) at 2.5 MPa Boiling Point: 4.222 K (-2683928 ºC or -452.070 ºF) Triple Point: 2.177 K at 5.043 kPa Critical Point: 5.1953 K at 227.45 kPa State at 20ºC: Gas Heat of Fusion: 0.0138 kJ/mol Heat of Vaporization: 0.0829 kJ/mol Molar Heat Capacity: 20.78 J/mol·K Atomic Radius: 1.40 Å Covalent Radius: 0.37 Å Van der Waals Radius: 1.40 Å Electron Affinity: not stable 1st Ionization Energy: 2372.3 kJ/mol 2nd Ionization Energy: 5250.5 kJ/mol Common Oxidation States: 0 - Helium is the lightest and least dense of the noble gases. - Helium was the first element to be discovered outside of Earth. The first evidence of the existence of helium was from spectroscopy data from the Sun. - Even though helium is relatively rare on Earth, it is the second most abundant element. Helium accounts for roughly 23% of all elemental mass of the universe. - Helium has the lowest melting and boiling points of all the elements. Creating solid and liquid helium takes extreme pressures and low temperatures. - Helium gas is colorless, tasteless, odorless, non-toxic and inert. - Most helium gas is extracted from natural gas deposits. - Radioactive emissions from α decay are helium nuclei. - Helium is the second least reactive noble gas after neon. - Inhaling helium gas can raise the pitch of a person’s voice. - Even though helium was discovered by its yellow spectral line, ionized helium gas has a reddish orange glow. Learn more about elements on the periodic table.

Our Sun is a star. It’s a vast ball made up of 74% hydrogen and 24% helium, with trace amounts of other elements. It has so much mass that the temperatures and pressures at its core are hot enough to ignite fusion. At the core of the Sun (and other stars), atoms of hydrogen are being fused into atoms of helium. This process releases a tremendous amount of energy. If an object isn’t performing some kind of fusion at its core, it’s not a star. Most planets are actually made of similar material to the Sun. Both Jupiter and Saturn have similar mixtures of hydrogen and helium. If the planet Jupiter is made of hydrogen, why doesn’t it shine like a star? It all comes down to mass. Jupiter would need to be about 80 times more massive before it had enough mass to actually ignite hydrogen fusion at its core. The small rocky terrestrial planets like the Earth and Mars make up just a fraction of the mass of the Solar System. Unlike the larger gas giants, the terrestrial planets are mostly made up of denser elements, like iron, silicon and oxygen. The larger gas giant planets probably have large quantities of these heavier elements in their cores. In fact, Jupiter probably has an Earth-like ball of rock with 14 to 18 times the mass of the Earth at its core. What about orbits? Planets orbit stars, no question. But you can also have multi-star systems where stars are orbiting stars. And it’s also possible that you could have binary planets orbiting a common center of gravity and together they orbit around a star. The end of the day, the only real difference between planets and stars is mass – almost everything out there is made up of 75% hydrogen and 24% helium. If an object has about 80 times the mass of Jupiter, it has sufficient mass and temperature to ignite solar fusion in its core. If it doesn’t… it can’t NASA: Cosmic Chemistry

A massive particle detector located a mile underground has found bits of antimatter known as geo-neutrinos deep inside the Earth. The find proves the Earth derives most of its power from radioactivity and could help us predict volcanoes and earthquakes. Geo-neutrinos are antimatter particles created by the radioactive decay of uranium, thorium, and potassium deep within the Earth's crust and mantle. Although geo-neutrinos had first been found in 2005, this is the first real confirmation that they originate in large quantities deep underground. The successful detection using what amounts to a geo-neutrino "telescope" also means geologists have gained a powerful new tool to examine what the Earth's interior looks like. The presence of these particles confirms radioactivity is a significant source of the Earth's internal power. It's long been thought that the decay of uranium and thorium heats up the Earth and contributes to convection processes in the mantle, in which rock flows steadily upwards, carrying extreme heat with it. This then powers plate tectonics, which is the primary force behind volcanic eruptions and earthquakes. Geo-neutrinos have now tipped the scale towards radioactivity as quite possibly the single biggest source of geothermal energy. So what are these particles? Their matter counterparts, the neutrinos, are chargeless and inert elementary particles that are emitted by the Sun and cosmic rays. They have almost no mass at all and can pass through matter leaving barely any disturbance at all. This all combines to make neutrinos incredibly difficult to detect, and scientists have to go to extraordinary lengths to find them. This particular detector is located a mile underneath Italy's Gran Sasso Mountain, a necessary step to put as much thick rock as possible between the device and surface radiation that might interfere with neutrino detection. But that's nothing compared to the detector itself. It's a massive nylon sphere containing 1,000 tons of hydrocarbon fluid. Around the sphere is a huge array of ultra-sensitive photodetectors that can hopefully spot the neutrinos passing through. And all of that is encased in a stainless steel sphere that in turn is suspended in 2,400 tons of purified water inside yet another steel sphere 59 feet in diameter. The device was originally built just to detect solar neutrinos, but the team soon realized they could also put it to use hunting for geo-neutrinos. Geo-neutrinos are thousands of times less common than their solar neutrino counterparts, and the detector only finds a few such particles per year. The most exciting practical application of the discovery of geo-neutrinos is the creation of a worldwide network that can sense the particles at various locations. This data could then be used to figure out what's going on inside the Earth in a larger sense, and with sufficient precision it would be possible to predict when volcanoes were going to erupt or when earthquakes were going to occur. This would provide humanity an early warning system that it still sorely needs. [via Physics Letters B]

L. TR’AFTON Astronomy Radiative greenhouse the temperature of the transport of heat. Observatory, Texas 78712 16, 1972; of Jupiter’s cloud level Neglecting convection, Sagan and Mullen (1972) performed a two-level radiative equilibrium calculation to derive a temperature between 270 and 340°K at the “effective reflecting level” of Jupiter’s lower cloud layer. As a consequence, they suggest that water, its compounds, and solutions form this reflecting layer. They reconcile this result with the measured rotational temperatures by suggesting that these are means over two distinct layers, ammonia cirrus at 120°K and dense water cumulus at 270-340°K. Assuming that infrared abundances near the center of the Jovian disk refer to gas quantities overlying the lower cloud layer, their analysis overestimates the temperature at the top of the lower clouds by 64 124°K. The amount depends on which thermal opacities their models include and arises from their neglect of the convective heat transport. In the convecting layers of Jupiter’s atmosphere, the vertical atmospheric motion transports part of the heat. What this means is that the temperature gradient must be less than that for radiative equilibrium because the net energy flux is fixed by solar insolation and the internal source of heat. For a reflecting level fixed by the overlying gas abundances, the shallower temperature gradient causes this level to be cooler than the temperature predicted by the corresponding radiative solution. I pointed out (Trafton, 1967) that less than 3Okm-atm H, provides sufficient thermal opacity to bring about convection Copyright 0 1973 by Academic Press, Inc. All rights of reproduction in any form reserved. atmosphere because they 22, 1972 seriously neglect in the underlying layers of Jupiter’s atmosphere. A model which I have recently computed (cf., Wildey and Trafton, 197 1) verifies that the top of Jupiter’s convective zone lies near 142’K and underlies 20kmatm H,. These results are not sensitive to the likely range of He/HZ abundance ratios. The opacities include H, and the rotational band of ammonia. Table 1 compares P(T) for this radiative-convective model and for the corresponding model in purely radiative equilibrium. Comparison of radiative models should be made for common compositions and pressure levels. The radiative portion of Table 1 corresponds approximately to Sagan and Mullen’s HZ-NH, model, except that they include the vibrational bands of ammonia. The latter, however, have only a minor effect on the structure which can be estimated on the basis of a comparison with the H,-CH, model. Interpolating the opacities in their models, we find that the temperature of the lower cloud zone of their model including H, and only the rotational band of ammonia would be near 246°K. This result is directly comparable to the corresponding level of the radiative model in Table 1. Observed HZ abundances fall typically in the range 50-80km-atm for Jupiter. If we take 80km-atm H, above Jupiter’s lower cloud layer, this puts this layer at a temperature of 237°K and a pressure of 1.8 atm in the radia,tive model. The difference between this temperature and the 246°K of the corresponding model of Sagan and Mullen is presumably due to Radiative convective” 1ogP (c.g.s.) Purely radiative 1ogP (c.g.s.) 100.5 102.3 104.4 105.0 105.6 106.1 106.6 107.1 108.7 110.3 112.5 113.8 114.9 116.0 117.1 119.0 120.7 122.3 123.7 126.4 128.8 131.0 133.1 135.1 137.0 141.8 146.6 151.4 156.4 164.5 170.4 181.4 190.1 204.5 216.0 225.9 234.6 242.3 258.7 272.4 284.2 3.783 3.934 4.173 4.325 4.436 4.587 4.675 4.738 4.889 4.987 5.091 5.140 5.180 5.214 5.244 5.294 5.335 5.369 5.399 5.450 5.491 5.526 5.556 5.583 5.608 5.659 5.704 5.750 5.795 5.865 5.913 6.000 6.067 6.171 6.250 6.315 6.370 6.417 6.515 6.591 6.655 5.659 5.702 5.738 5.769 5.822 5.866 5.936 5.991 6.076 6.140 6.192 6.236 6.273 6.350 6.409 6.458 a Convection begins starting tabulated values in the purely column. For lower temperatures, pressures in the two models are The point-by-point convergence 0.5% in the flux. The maximum is ratio is 6.7 x 10m4; ammonia to be saturated when its vapor gives a smaller mixing ratio. with the radiative the the same. is to NHJH, assumed pressure their approximate treatment of the band transmissions and to a somewhat different choice of gas abundance overlying the lower cloud tops. In our radiative-convective model, this pressure level has a temperature of 2 16°K ; convection cools this level by 21°K. We note here that this result is compatible with a fairly transparent cloud layer at the 120°K level, at least for observations near the center of the disk. The essential point to realize now is that the addition of further thermal opacities, which are minor constituents to this radiative-convective model, will slightly elevate the top of the convective zone but leave the adiabatic gradient essentially unaltered. Adding such thermal opacities to the convecting region of the atmosphere does not affect the temperature of the lower cloud top (in the first approximation) as it definitely would if added to the purely radiative model. The radiative models of Sagan and Mullen illustrate the sensitivity of the lower cloud temperature to opacity. The 340°K value derived by including the opacity of water in their models is over 120°K higher than the temperature of the same pressure level in the same model where convective motion is permitted. These considerations suggest that the spectroscopically-determined temperatures really are representative of the absorbing layer and that any lower cloud layer is too cold to consist primarily of water cumulus clouds. My model neglects the high-altitude absorption of sunlight by methane, but this has only a small influence on the deeper structure because the magnitude of the internal heat source insures that convection occurs throughout this region. It remains to verify that the P(T) . relation in the convecting region (cf., Trafton, 1967) holds in spite of the short time constants for large scale dynamics in Jupiter’s atmosphere. Gierasch and Goody (1969) showed that this time constant is much shorter than that for radiative processes in these layers. Stone (1972), however, has recently shown that the Jovian atmospheric dynamics specify a lapse rate which differs from the convective one by only one part in 1 04. Since radiation to space sets a boundary value to the resulting P(T) relation, the use of a radiative-convective model for supporting my above conclusions should be adequate. REFERENCES GIERASCH, P., AND GOODY, R.(1969).Radiative time constants J. Atmos. Sci. in the 26, 979. G.(1972).TheJupiter greenhouse. Icarus 16, 397. STONE, P. (1972). A simplified radiativedynamical model for the static stability of rotating atmospheres. J. Atmos. Sci. 29, 405. TRAFTON, L. (1967). Model atmospheres of the major planets. Astrophys. J. 147, 765. WILDEY, R., AND TRAFTON, L.(1971).Studiesof Jupiter’s equatorial thermal limb darkening during the 1965 apparition. Astrophys. J. Suppl. 23, l-34.

Bakersfield Night Sky – March 3, 2018 By Nick Strobel There are more than 100 billion galaxies in the observable universe and keeping on eye on each one of them is, shall we say, “difficult to do”. A supernova will happen in a galaxy roughly once-a-century. Seems like a long time to wait but when you have 100 billion galaxies to work with, there will be many supernova going off somewhere in the universe in any given year but where should you look to catch one just beginning to happen? Even with all the huge array of telescopes pointed up at the sky on any given night around the world for many decades, we haven’t caught a supernova in its beginning stage. That is until Victor Buso, an amateur astronomer in Argentina, pointed his telescope at NGC 613, a spiral galaxy about 68 million light years away from us, so we are seeing the galaxy as it was 68 million years ago. Up until Buso’s observation, no one had seen the “shock breakout phase” of a supernova that occurs in the first few hours as the shockwave from the sudden core collapse, that triggers a supernova, reaches the huge star’s surface. When the shockwave reaches the star’s surface, the gas layers heat up, blast outward, and the star gets brighter and brighter at a rate of ten quadrillion times per day. (I had to look up what number equals a thousand trillion—“quadrillion” is the name for that number.) After Buso and another amateur astronomer friend of his, Sebastian Otero, sounded the alarm, other ground-based research telescopes and space telescopes were pointed at NGC 613 to catch those precious photons encoded with all sorts of information about the death of a star much more massive than the sun. Only the very massive stars will have the violent death of a supernova. These stars are very rare—much less than 1% of the stars out there. Most stars, including our sun, will have a gentler way of dying. Analysis will continue on the observations being gathered from this supernova but Buso’s observations already do finally confirm the theoretical models of what happens in the first several hours of a supernova explosion. Closer to home another brilliant spot continues to climb higher up in the early evening sky. That spot is Venus which is now probably high enough to be above the dust and smog layer after sunset. Venus’s separation from the sun as seen from Earth will increase through spring and we’ll have an easier time seeing. Venus appears so bright in our sky because it is the closest planet to us and its clouds made of sulfuric acid droplets reflect 77% of the sunlight reaching Venus. One popular science article I read said that Venus is so bright because of its thick atmosphere. The picky astronomer in me said, “No, the thickness of atmosphere doesn’t make it reflect so much sunlight—the clouds do and they make up a teeny tiny (to use a highly technical scientific term) fraction of its atmosphere.” Venus’s atmosphere is 96.5% carbon dioxide and 3.5% nitrogen both of which are transparent to visible light. The other trace gases (like sulfur dioxide, argon, and water vapor) are measured in parts per million. The carbon dioxide is not transparent to infrared energy which is why Venus is so darn hot (another technical scientific term). Carbon dioxide is a greenhouse gas that traps infrared energy close to the surface and Venus has a lot of it—its surface air pressure is 92 times higher than Earth’s. Tonight you’ll see Mercury right next to Venus about a thumb width at arm’s length to the right of Venus (see the inset of the star chart below). Speedy Mercury will climb higher past Venus and reach its greatest separation from the sun on March 15 but it will get slightly dimmer as it does so. The moon was at full phase yesterday, so we’ll get a “blue moon” at the end of March but no lunar eclipse. The moon will be at perigee (closest to Earth) on March 26, so no “supermoon” either. Tonight the gibbous moon will rise shortly after 8 p.m. and wash out most of the sky for the rest of the night. Early risers will see a nice line-up of the outer planets, moon, and the two bright stars Antares and Spica. In tomorrow morning’s sky, the order from left to right will be Saturn, Mars, Antares, Jupiter, Spica, and the moon. You might have a hard time seeing Spica next to that bright moon. The star chart below shows the moon’s motion over the next several mornings. On March 10, the waning crescent moon will form a beautiful triangle with Saturn and Mars. Director of the William M Thomas Planetarium at Bakersfield College Author of the award-winning website www.astronomynotes.com

This diagram illustrates the evolution of Rosetta’s dual-lobed comet, 67P/Churyumov-Gerasimenko, over the past 4.5 billion years. The comet is thought to have formed this long ago in the primordial disc of the Solar System, perhaps as two small objects slowly collided and stuck together. Comets form in the icy outer Solar System and are stored there in vast clouds before beginning their journey inwards; comet 67P/C-G is thought to have entered the giant planet region hundreds of thousands to millions of years of ago. By this point a form of geological erosion named mechanical shear stress had taken hold, and was the dominant process sculpting and shaping the comet’s surface and interior. A new study using data from Rosetta found this stress to peak in the region connecting the two lobes of the comet: the ‘neck’. This neck bore the brunt of mechanical erosion, fracturing and thinning over time – as shown in the diagram by the cross-hatched lines. The final steps cover the time period from tens of thousands of years ago to present day, a period during which sublimation erosion was dominant in shaping the comet’s surface and interior. This kind of erosion takes place as the Sun warms ices within the comet, causing the ice to turn to gas and escape to space, carrying cometary material along with it. This weakened the comet’s neck further, and the force grew stronger as it travelled inwards from Jupiter’s orbit towards Mars. It is important to note that the red arrows do not imply cometary rotation; instead, they represent shear deformation, and illustrate the torque generated at the neck.

Dale P. Cruikshank and Joseph W. Chamberlain Copyright © 1999 by the American Astronomical Society. This article originally appeared as a chapter in The American Astronomical Society's first century volume edited by David H. DeVorkin. 1999. Pages 252-268. ISBN 1-56396-683-2. We trace the origins of the Division for Planetary Sciences as the premier scientific society in North America for the promotion of planetary science. There was a time when the work of every major observatory in the United States included the astrometric or physical study of the myriad bodies of the Solar System. To appreciate fully the reasons for the creation of the Division, we must recall the highlights of the history of the subject matter area itself. Whether it was the positions of comets and asteroids, visual observations of the seasonally shifting tones of Mars' surface, the motions of planetary satellites, or the spectroscopy of Saturn's rings, planetary observations figured significantly in the regular programs of Lick, Yerkes, Harvard, Yale, the U.S. Naval Observatory, and others. In the early 1900s, with the emergence of modern astrophysics, and perhaps partly as a consequence of the huckster-like promotion of Mars as the habitat of a technically advanced civilization, based on questionable visual observations, planetary astronomy was somewhat de-emphasized among professionals. While planetary astronomy continued at various institutions, the research of most American astronomers with an interest in the planets assumed a low profile and was conducted in parallel with work on stars, galaxies, or other topics. The story is much more complex than can be summarized in a few sentences, but the net effect was that a rebirth of planetary astronomy occurred in post-war American science, largely through the special efforts of a very few astronomers, aided by the patronage of the U.S. Government through the military and the agency that became the National Aeronautics and Space Administration.[1,2] In the late 1940s, planetary astronomy began to evolve into a more broadly based planetary science, as the result of several specifc events. German V2 rockets captured at the end of World War II were used at White Sands Proving Ground to take pictures from more than 100 km altitude, showing large-scale views of the geology and geography of the southwestern U.S. This helped give us some of our first perceptions of the Earth as a planet. This new material was incorporated into the program of a conference organized by the Dutch-born American astronomer Gerard P. Kuiper at the Yerkes Observatory, September 8-10, 1947, in conjunction with the fiftieth anniversary of the Observatory. The conference volume, The Atmospheres of the Earth and Planets, included contributions by astronomers, meteorologists, and “high-altitude specialists.” A second, revised edition was published in 1952, and included an updated version of one of Kuiper's most significant papers on the atmospheres of the Earth and other planets from an observational and cosmochemical point of view. The development of Kuiper's interest in the bodies of the Solar System has been described by Cruikshank and by Kuiper himself.[4,5,6] At the same time, the origin and chemistry of the planets had caught the interest of Nobel Laureate Harold C. Urey, who published his landmark book, The Planets, Their Origin and Development, in 1952, which brought the study of the Solar System clearly within the view of chemists and geochemists, and offered a perspective on the Moon and planets of interest to traditional geologists. In 1953, Kuiper edited the first of his four-volume compendium on the Solar System, The Sun, and the next year The Earth as a Planet, the cover of which shows a picture of a piece of the desert southwest from a V2 rocket.[8,9] This book clearly established the study of the planets as an interdisciplinary enterprise. Not only were the interior, mantle, and crust of the planet explored, but the dynamics of Earth and its interaction with the Moon were covered, as were its oceans, all levels of the atmosphere, and the aurora. Significantly, the biochemistry of the atmosphere was a part of this truly global view of Earth. Those aspects of Earth (albedo, color, polarization) that can be directly compared with telescopic observations of other planets, were reviewed by astronomer André Danjon. Inklings of what has more recently become a systems view of Earth's oceans, crust, and atmosphere, are seen in this extraordinary book. Although by the early 1950s planetary science had taken on the status of a multidisciplinary endeavor in principle, interested scientists continued for many years to approach their research from the vantage points of their foundations in the traditionally defined fields of astronomy, geology, meteorology, chemistry, and to a lesser degree, biology. Not until the 1970s did there emerge explicit university curricula in planetary science. It is facile to abbreviate the story of the development of planetary astronomy in these few paragraphs, using conferences and books as guideposts; the details are compelling and interesting, particularly when they are derived from primary sources. Those details, with commentary, are given by Doel in a book that is an essential resource for understanding the development of studies of the Solar System in America. A key turning point in American planetary science was the formation, in 1969, of the Division for Planetary Sciences (DPS) of the American Astronomical Society. It is the story of the origins of the DPS that we tell here. The view of the emergence of planetary science from its birthplace in astronomy, and in particular the establishment of the DPS, has been described by one of the present authors, who helped define the multidisciplinary character of the field by organizing the first national society devoted to it. The present paper draws upon Chamberlain's reflections and perceptions, and it is augmented by key documents and accounts of pivotal events, mainly covering the period 1967-1971. Specialists and Generalists Young astronomers entering the field are commonly overwhelmed when attending their first full meeting of the AAS. Throngs of astronomers surge into multiple meeting rooms as the overlapping sessions begin early each morning. At coffee breaks the corridors are awash with astronomers lined up to fill their styrofoam cups with “the fuel of science.” The din slowly rises as conversations accelerate, and then the sessions resume as the participants file back into the meeting rooms for more 5-minute presentations by them and their colleagues. This goes on for several days, and even the evenings are occupied with special presentations, the banquet, the business meeting, committee meetings, and more. Years ago, AAS meetings were attended by fewer than 100 astronomers, sessions were serial rather than parallel, and presentations were far less hurried. Furthermore, each American astronomer was acquainted with the person and the work of every other American astronomer. The same situation prevailed elsewhere in the world; the late Boris A. Vorontsov-Velyaminov of Moscow, told one of us (DPC) in 1969 that he once knew every astronomer in Russia, but by 1965 he didn't even know all of the astronomers working in his own institute (Sternberg State Astronomical Institute). This depersonalization, brought about by the population explosion within science, has afflicted most of the major scientific societies. As the attendance at meetings swell, the organization is overpowered and can no longer accommodate in three or four days of leisurely sessions all of the contributed papers, along with various special sessions and activities that must accompany a major meeting. The members must then choose from a variety of unpleasant alternatives, including a longer meeting, shorter papers, “poster” sessions, relegation of some papers to the status of “read by title only,” or holding two or more simultaneous sessions for contributed papers. (see DeVorkin and Routly page 122.) Simultaneous sessions were the dreaded Final Solution, ‘devoutly to be fear'd,’ especially by generalists. A generalist is an individual who understands quite a bit about every aspect of the entire subject of astronomy. In 1950, such a person attended most of the meetings of the AAS and read The Astrophysical Journal from cover to cover—all 130 papers per year, 1200 pages per year. In 1996, the ApJ published about 1800 articles in 18,450 pages, not counting the Letters and the Supplements; did any one person read all that? Even the Editor? Today the vestigial generalist attends both AAS meetings and one or two special meetings per year, and knows that if two sessions are run simultaneously, he will certainly miss something important. Specialists, on the other hand, confine their interest to one major area of astronomy. They organize and attend their own conferences, sometimes publish in a specialty journal, and they agitate for a professional society that caters to their specific interests. As specialty groups spin off from a larger scientific society, two opposite effects occur. First, the specialty is strengthened, but its practitioners grow further from the broader, overarching subject. The compensating effect is that other specialists from other fields soon join with the splinter group and the new amalgam develops a character all its own. In the present case, when the planetary astronomers were no longer regarded merely as astronomers, scientists from other planetary disciplines (e.g., geophysics, atmospheric physics) joined with them in their new society. As the population continues to grow, the inevitable and undesirable happens: the specialist society becomes too large to accommodate all activities, and its annual meetings suffer the same compressional fate as the original parent society did. Multiple sessions, large crowds, and unwieldy business meetings ensue. Furthermore, the “generalist” emerges anew, but redefined as a planetary generalist rather than an astronomy generalist. Filling the Need Interest in the moon and planets got a big boost with Sputnik in 1957, as did every other scientific and technological endeavor in the United States. Tatarewicz has traced the post-Sputnik development of planetary science as the U.S. military sought specific information on the suitability of the moon and other bodies in space in the context of national security. At the Pentagon's behest, NASA looked for people “who knew what they were doing” when it came to understanding the Solar System. The priority given by NASA to such specific things as determining the thickness of the lunar regolith, the surface pressure on Mars, and the water content of Venus' atmosphere, fostered the agency's sponsorship of the construction of three (later four) major telescopes and various other facilities. At the same time, NASA funding managers supported the activities of Kuiper and others to establish multidisciplinary university curricula in the new and broadly defined field of planetary science. The growth in interest in the Solar System, plus the increasing facilities with which to conduct observations at the telescope and in the laboratory, and especially the exploration of the planets with spacecraft, created pressure within the community of planetary scientists to conduct their own meetings and eventually to establish their own society. The journal Planetary and Space Science began publication in 1959, and in May, 1962, Academic Press published the first issue of Icarus, an international journal devoted entirely to Solar System research. To accommodate the increased need to maintain open lines of communication, various small conferences were created by planetary scientists. In the 1950s, Lowell Observatory hosted workshops on planetary atmospheres, and beginning in early 1967, a series of five annual symposia was organized by staff members of the Planetary Sciences Division of Kitt Peak National Observatory (KPNO). The Planetary Science Division at KPNO consisted of about a dozen professionals, including J. W. Chamberlain, M. J. S. Belton, J. C. Brandt, D. M. Hunten, Michael McElroy, Darrell Strobel, Lloyd Wallace, and frequent visitor Richard Goody. It was at that time one of the larger specialty groups in planetary science in the country. Together with the staff and students in Kuiper's Lunar and Planetary Laboratory, just across the street at the University of Arizona, there was a large concentration of planetary science talent in Tucson. The Arizona Conferences on Planetary Atmospheres, as they were called, focused on different specific themes at the annual gatherings. In 1967 it was “The Atmospheres of Venus and Mars,” in 1968 it was “The Atmosphere of Venus,” in 1969 “The Atmospheres of the Jovian Planets,” in 1970 “Motions in Planetary Atmospheres,” and then “Aeronomy of CO2, Atmospheres” in 1971.[12,13,14,15,16] Thus, planetary scientists had a forum for publication, and various means for organizing relatively small meetings, but a professional society was needed to bring planetary scientists of all persuasions together. Birth of the DPS The Space Science Board of the National Academy of Sciences convened a Panel on Planetary Astronomy, which held its organizational meeting in Tucson in late February 1967. This meeting, chaired by John Hall, was held in conjunction with the first of the Arizona Conferences. At its Summer Study at Woods Hole later that year, the Panel wrote its report, “Planetary Astronomy: An Appraisal of Ground-Based Astronomy.” The report stated that “The establishment of a national society for planetary sciences or of an affiliate of an existing society would be highly desirable to serve as a forum for discussion and a cohesive force to facilitate recruitment of personnel, to assist in obtaining financial support or facilities for projects of unusual merit, and to encourage publication of results.” Tobias C. Owen noted that it was Juan Oro who initially argued at the summer study for a separate society. He also recalled that “Juan's suggestion became one of the study's recommendations. I went to Gerard [Kuiper] with this idea, but he declined to get involved, suggesting I talk to Carl [Sagan] instead. Carl in turn consulted with Frank [Drake].” Building on a draft composed by Drake, Sagan and Owen composed the second draft of a letter to Albert Whitford, then President of the AAS. On February 1, 1968, Sagan and Owen sent this draft to a number of colleagues with a cover letter. Noting that there was favorable reaction in the community to a specialized society, but that the actual structure of such a society was the subject of debate, Owen and Sagan noted that: Possible conflicts with existing groups and the undesirability of additional journals and meetings have been cited as arguments against the formation of a new, completely independent organization. It is our opinion that the best hope for the realization of our common goals lies in the proposal outlined in the accompanying letter [to Whitford]. It is suggested that we begin by forming as [a] branch of the American Astronomical Society that would be concerned primarily with Solar System problems. We have chosen the AAS for this purpose because most of the scientists interested in these problems are already members and because it appears that fractionation of the Society into subspecialties is already occurring to accommodate the needs of solar physicists. By maintaining an affiliation in this way, we can avoid the difhculties inherent in the formation of a new organization, although such a step may become desirable at a later date. A necessary prerequisite for the proposed arrangement would be permission from the AAS to hold relatively autonomous meetings that would include an interdisciplinary flavor, a concentration on problems of special interest, and opportunities for extensive discussion which are currently lacking in meetings sponsored by the existing organizations. The letter concluded with a solicitation for approval of the letter to Whitford, to be indicated by the recipient's signature on that letter, to be taken also as agreement to participate in the organizing committee for the first meeting, “...which might be held in the fall or winter of 1968-1969.” At the same time Sagan and Owen canvassed their colleagues, they drafted a letter to Whitford outlining what they had in mind and laying out the substance of the issues that were at stake. In brief, Sagan and Owen suggested that the AAS “sponsor annual or semi-annual scientific meetings devoted entirely to solar system studies, excluding solar physics.” They envisioned meetings that would be similar to AAS meetings, but focussed on one specialty allowing for more time for the presentation and discussion of papers. “Our concern for such meetings is motivated by the rapidly increasing interest and activity in the entire range of solar system studies, and by the lack of regular scientific meetings in which there is adequate time to present new results and related discussion. In fact, as a result of the diverse backgrounds of the scientists working in these areas, no suitable forum is currently available for the regular exchange of ideas and results on problems of mutual interest.” Lunar and planetary atmospheres, surfaces, and interiors, and relevant investigations of asteroids, meteorites and comets were the topics Sagan and Owen identified, but they also wanted to encourage broadly based interdisciplinary participation: “We would encourage participation by specialists in celestial mechanics who are interested in problems associated with the evolution of the solar system, such as spin-orbit coupling. In addition, we would like to invite scientists who are not members of the AAS to give papers, particularly in such areas as chemistry, geology, and biology, where significant contributions to the field can be expected.” Sagan and Owen recognized that there were alternatives, such as transferring attention to other professional organizations, “as has been attempted diffusely and without vigor by the American Geophysical Union,” which they thought was a “poor solution.” They also argued that the formation of a new society was: ... unnecessary and undesirable in view of the existence of the AAS, which we feel provides a basic organizational structure and atmosphere - in particular an appropriate balance between formality and informality - which engenders productive interaction among scientists. The leading figures in solar system science seem closest, in the majoriy of cases, to the AAS. It also appears to us that there is no need for an additional journal, removing what might be a minor argument for a new sociey. We conclude that retaining solar system studies in the AAS is the most desirable means, at least for the present, to nurture growth in this field. Among the recipients of the February 1 draft, apparently only Anders and Chamberlain made substantive suggestions for changes. Anders thought that clarification of the issue of the formation of a “branch” of the AAS devoted to solar system problems was needed, since such a suggestion did not appear explicitly in the letter to Whitford. Anders also favored holding the planetary meetings in conjunction with AAS meetings. He suggested that such meetings might be organized as symposia, thereby “enhancing the attractiveness of the AAS meetings for people with interdisciplinary interests.” He did not want the planetary meetings to appear to be a “wholly separate activity run as a service by the AAS.” Anders' suggestions were followed, so the letter finally sent to Whitford on March 18, 1968 argued that by creating symposia, “it would be possible to hold joint sessions in conjunction with regular AAS meetings when this appeared to be desirable.” This would encourage scientists with interdisciplinary interests to attend AAS meetings, “while astronomers with an interest in planetary research would have an opportunity to confer with specialists from other disciplines. If the AAS should ultimately find that it is necessary to develop subgroups devoted to various branches of astronomy, participants in the proposed symposia would form a nucleus for the organization of a group devoted to planetary research.” When Owen discussed their proposal with Whitford prior to crafting the final version of the letter, he learned that, as he later told those who had shown interest, “we have chosen a favorable time for our appeal.” The Council was then also hearing from other solar and high energy specialists who were calling for similar recognition, and was planning to take the matter up at their next meeting in April 1968. John Firor was already taking the initiative among solar astronomers, while Eugene Parker was doing the same for the high energy astronomers. Owen and Sagan reported that Whitford wanted to “retain solar-system studies within the framework of the AAS and would support their effort ‘If no complications arise ...’.” Within the month, Owen learned from Whitford that the Council was “favorably disposed” to their petition, “In fact the Society plans to cooperate with sections of the membership interested in holding meetings devoted to the discussion of one restricted topic. This has already been done by the solar physicists and there will be others.” The Secretary of the AAS, G. C. McVittie, had already been in touch with Harlan Smith about holding a planetary meeting on the day before the Austin meeting of the full AAS in December 1968. He offered the help of the Secretary's office in mailing announcements and in giving advice on procedure, but noted that the organizing committee of the planetary group would have to do the organizational work for the meeting itself, and suggested that the solar physics people, who had done it twice before, might offer useful suggestions. The AAS meeting was scheduled in Austin in part to celebrate the opening of the NASA-funded Texas planetary telescope, and Whitford noted that a special meeting on planetary astronomy held in conjunction with the regular meeting would be particularly relevant. Pointing out that “The Council views the format as an experiment,” Whitford reported that the Council wished that “the purpose of these restricted one-topic meetings will in general be best realized by a two-day meeting at a separate time and place.” The Council was very interested to have the planetary astronomers' reaction to this suggestion, because it opened the door for future meetings held at times and places completely independent of the AAS general meetings, while the option remained for contiguous meetings as well. Smith wrote to Owen to begin preparations for the Austin meeting, proposing to call the planetary session the “Special Meeting of the AAS on [Planetary Astronomy] [or whatever].” He told Owen that “Our fliers should be mimeographed or multilithed on a special conspicuous color of paper, and sent to McVittie, 2500 copies, unfolded.” On May 8, 1968, Owen and Sagan distributed the Whitford letter (of April 12) to their original list, with the cover memo soliciting input on possible topics for the Austin meeting. They proposed four possibilities: - Interpretations of cratering statistics for the moon and Mars. - Spin-orbit coupling and tidal effects in the solar system. - Organic molecules in the early history of the solar system. - Problems in planetary atmospheric circulation. These topics reflected the interests of the day. The Apollo 11 lunar landing just over a year away, and a session on crater studies would appeal to geologists working on planetary problems. Sagan's own interest in organic matter in the Solar System was clearly represented, although few astronomers were interested in the topic at the time. With new data, old classical problems of planetary spins and resonances involving orbital periods were being reopened by a number of young scientists, rekindling the field of gravitational astronomy. Finally, planetary atmospheres appealed to much of the core group of Solar System researchers, certainly those who had attended the Tucson conference series sponsored by KPNO. Not everyone had the same priorities, of course; Smith replied to Owen that his own interest in the proposed topics was exactly in the reverse order to that which had been given in the memo. On July 17, Whitford in Santa Cruz phoned Chamberlain, who was spending part of the summer in La Jolla, to say that the AAS was about to send out a mailing on the organization of divisions. It was to contain guidelines for setting up the official machinery, and of course everything had to be consistent with the Constitution and bylaws of the Society. Chamberlain was asked to nominate about eight people for the Organizing Committee for a Division for Planetary Sciences. The first meeting would probably be in Austin at the time of the AAS meeting in December, and would afford an opportunity to set down the Divisional bylaws. Rather than have an earlier meeting to get started, Chamberlain preferred to communicate with his small organizing committee by phone and letter. Secretary McVittie wrote to Chamberlain and the other committee members officially announcing the Council's action: At the Annual Business Meeting of the Society on 22 August 1968, the membership approved the institution of Divisions of the American Astronomical Society devoted to Special Subjects. One such Division is that on Planetary Astronomy. The Council at its meeting of August 20, 1968, had agreed that you should be the members of the Organizing Committee for the Division on Planetary Astronomy. McVittie added that their first task will be to draw up bylaws for the Division, perhaps following the method used by the AAS. He asked for the proposed divisional bylaws in time for presentation to the Council at its meeting of December 10, 1968. Chamberlain was thus put in charge of organizing the planetary scientists, although Sagan and Owen had taken the initiative and gotten the attention of the Society. Chamberlain later wrote that on the basis of the Sagan and Owen letter alone the AAS would not likely have responded by setting up divisional structures. Had it not been for the pressure brought by the high-energy astronomers, the planetary astronomers might have gone down one of the alternate routes that were emerging. In particular, Chamberlain notes that because of the regard in which planetary astronomers were held in the American astronomical community in the 1960s, pressure for a special section of the AAS to accommodate Solar System interests would probably have resulted in an “invitation” to set up a completely separate society, had it not been for pressure from other astronomers in the AAS in pursuit of their special interests. The high-energy astrophysicists (including John Simpson, William Kraushaar, George Clark, Herbert Friedman, Eugene Parker, and others) had been agitating for a reorganization of the AAS that would accommodate the particular needs of their subdiscipline. Chamberlain asserts that the threat to secede by this influential community, “followed by the successful diplomatic intervention by Martin Schwarzschild, convinced the Council that divisions were definitely in the Society's future, like it or not.” Schwarzschild's positive role in the reorganization, which was surely dreaded by the Council, proved to be critical to the successful birth of the DPS and to other divisions of the Society. Chamberlain recounts the events, noting that in 1966 Bengt Stromgren began a two-year term as President of the Society, but resigned after one year to return to Copenhagen. Albert Whitford, as the senior Vice-President, became Acting President for 1967-1968. Although Whitford began his own two-year term as President on July 1, 1968, he had previously committed to take a sabbatical leave at Mount Stromolo Observatory in Canberra, Australia, beginning in the late summer of 1968. In his absence from the U.S., Martin Schwarzschild, at that time the senior Vice-President, carried out the duties of President until Whitford returned in mid-1969. At that time Schwarzschild assumed the newly created office of President-Elect for 1969-1970 and became President for 1970-1972. This series of events put Schwarzschild at the center of action during the time of the reorganization to accommodate the new divisional structure of the Society. As Whitford recalled, “I felt that I could go away with a good conscience, since the problem of dealing with the mounting pressure for specialized divisions in the AAS would fortunately be in the capable hands of Martin Schwarzschild.” As Chamberlain drafted the bylaws of the planetary division, he was in frequent communication with Schwarzschild, exchanging ideas by letter and telephone. Schwarzschild worked to ensure that there were no conflicts with the Society's governing rules and that the emerging “Division did not go charging off in all directions without parental restraint.” Chamberlain was intent on “ensuring a high degree of independence in the Division's operations: e.g., by allowing the affiliation of non-astronomers, in order to make the Division the preeminent society of its kind in the world.” Indeed, the individuals on the Organizing Committee covered nearly all areas of planetary science as it was seen at the time, although Sagan in particular had suggested others with an interest in exobiology to Chamberlain. Overshadowing Chamberlain's efforts to draft the bylaws was the knowledge that the approval of the AAS Council was mandatory to guarantee the success of the venture. On September 17, 1968, well in advance of the organizational meeting to be held in Austin, Chamberlain, acting as Temporary Chairman, wrote to his Organizing Committee noting that one day of meetings of the Committee (December 9) would be adequate to get the bylaws in final shape for presentation to the AAS Council on December 10, which would be their own day “devoted exclusively to the scientific sessions on planetary astronomy.” Chamberlain then set out the functions of the Committee as follows: If the Organizing Committee can accomplish its functions at the Austin meeting, it could presumably pass out of existence at that time. However, until procedures are established for other members of the AAS to affiliate with the Section, membership of the Section consists solely of the Organizing Committee, who will presumably select the initial slate of Section ofhcers at the Austin meeting, in accordance with procedures outlined in the Section bylaws adopted there. Chamberlain added that to proceed “as expeditiously as possible” he appointed Carl Sagan as Temporary Secretary of the Section. Sagan would work with the AAS Secretary to make arrangements for Austin and to publicize the meeting. “I have just learned from Martin Schwarzschild,” Chamberlain reported, “that the Amendment to the Society bylaws for the ‘Introduction of Divisions of AAS,’ as adopted in Victoria, authorizes the Temporary Section Chairman to conduct the election of the Permanent Chairman of the Organizing Committee without necessarily awaiting the formality of a meeting. I favor this provision as it will allow the Permanent Chairman to organize the Austin meeting well in advance, and hopefully this should accelerate the formal organization of the Division.” Chamberlain enclosed a ballot card with instructions to return it to Toby Owen, the Teller for the first election. He also invited input to the Section bylaws. The result of the voting was that Chamberlain was elected Permanent Chairman of the Organizing Committee, to serve until the election at the Austin meeting. On October 1, 1968, Chamberlain wrote to a wider list of scientists interested in the organization of the planetary sciences division, noting the Council's approval to proceed. He issued a call for papers for Austin. The morning program was to consist of an interdisciplinary symposium on “Organic Matter in Meteorites and on the Moon” (chaired by F. L. Whipple) and one on the “results of the most recent optical and radar investigations of the asteroid Icarus, chaired by Dr. A. Kliore.” The afternoon session was to consist of contributed papers on lunar and planetary topics. Titles and abstracts were to be sent to Sagan. Figure 1. In the 1970s, Carl Sagan expressed how planetary sciences were changed by the space age: “In all the history or mankind, there will be only one generation that will be first to explore the Solar System, one generation for which, in childhood, the planets are distant and indistinct discs moving through the night sky, and for which, in old age, the planets are places, diverse new worlds in the course of exploration.” Carl Sagan, Cosmic Connection (New York: Anchor/Doubleday, 1973), p. 69. Photograph from the Cosmos series, courtesy ASP Archives and Andy Fraknoi. The Organizational Meeting, Austin, December 1968 In mid-October, Chamberlain distributed draft bylaws to the Organizing Committee, but Anders was the only one who “did his homework” and provided substantive input to a revised draft that was put on the table on December 9 in Austin. Chamberlain recalls that “the Committee worked hard all afternoon, then recessed for a Mexican dinner and a stop at a wine shop, where Anders and Goody tried to ‘out-winesmanship’ one another. The result was that we had a peculiar combination of Chilean and Portuguese wines to speed up the decision making process in our evening session.” At Austin an initial slate of officers was selected by the Organizing Committee from its own membership, with Anders nominated for Vice-Chairman and Chamberlain for Chairman. Nine people were nominated to fill six staggered terms as Committee members over the next three years. The Division membership was established by a list drawn up by the Organizing Committee including everyone thought to be interested in becoming a member. Owen was appointed (over his objections) to Secretary-Treasurer pro tem, and arrangements were established for a Nominating Committee to be selected by the full membership at the first annual business meeting. The official program agenda of the 128th meeting of the AAS, distributed in advance of the Austin meeting, did not show that the special planetary meeting was scheduled for Tuesday, December 10, only that the Council would meet that day, followed by registration and an informal reception. Deeper in the brochure, however, under “Notices,” was the following: Symposia. An interdisciplinary Symposium on Organic Matter in Meteorites and on the Moon, followed by papers on the asteroid Icarus will be held on December 10, 1968, at the University of Texas, Austin, Texas. Details may be obtained from Dr. Carl Sagan... The AAS program made no specific mention that this symposium might be related to the formation of a new Division of the Society, or was even associated, except by proximity, with the 128th meeting of the AAS. The regular program of the AAS meeting included nine contributed papers about the Moon, Venus, Jupiter, comets, Pluto, and the origin of the Solar System, all presented on Wednesday, December 11. Nevertheless, the special planetary science session on December 10 was a success. In Session I chaired by Arvidas Kliore, five papers about asteroid 1566 Icarus were presented, followed by discussion. Session II on organic matter was chaired by Whipple. In that session Sagan provided an introduction, followed by a review on organic matter in meteorites by M. H. Studier, R. Hayatsu, and Anders. John Oro followed with “Carbonaceous Matter in Meteorite & Lunar Samples,” Stanton Peal on “Water on the Moon,” and P. R. Bell on “Lunar Sample Analysis in the Lunar Receiving Laboratory.” A 30-minute panel discussion including the presenters, plus Harold Urey, Harold Masursky, and A. G. W. Cameron, finished up the symposium. The afternoon session consisted of 24 papers, including a special invited presentation by Urey on the history and implications of lunar mass concentrations. Tidying Up the Details On December 30, 1968, following the Austin meeting, Chamberlain sent a memorandum to the “Organizing Committee of the Division for Planetary Sciences.” Note that the name now clearly identified planetary sciences rather than planetary astronomy. With this memo he solicited lists of individuals who may wish to be affiliated with the DPS. In January, Chamberlain wrote to Schwarzschild to expand upon a few items in the draft bylaws submitted to the Council by the DPS Organizing Committee. In particular, a provision was included to encourage involvement of outstanding foreign scientists in the DPS meetings, somewhat above and beyond the degree to which the AAS had at that time become accustomed. In particular, the DPS wanted its Committee to be able to designate especially worthy planetary scientists outside North America as Foreign Affiliates of the Division, giving them full rights to attend and present papers at the Division meetings. Other items were organizational details concerning co-opted Committee members and the term of the Secretary-Treasurer. Schwarzschild was concerned about the introduction of Foreign Affiliates desired by the DPS. He asked Chamberlain to clarify a few points about the election of Affiliates, but his main concern was that “...we could not defend it to the AAS membership at large if we spend funds or appreciable energies of our AAS officers for the benefit of people who are not members of [the main body of] the AAS.” Neither Chamberlain nor Anders were happy about Schwarzschild's allusion that the AAS Council might limit the Division's autonomy on the admission and treatment of Foreign Affiliates,[37,38,39] but in a memo to the Organizing Committee, Chamberlain noted that the AAS Council had considered the Division's bylaws at their meeting in Honolulu, and the results of the deliberations were communicated to Chamberlain by the Executive Officer H. M. (Hank) Gurin, who would also be acting as the liaison officer for the newly established Divisions. Among other changes requested by the AAS Council, the issue of Foreign Affiliates surfaced. The version advocated by the Council (denoted Version B by Chamberlain), changed the qualification from one of “recognized accomplishment” to “outstanding accomplishment,” and imposed a limit of five percent of the Division membership for the Foreign Affiliate category. Chamberlain expressed his personal view that the Council was making a mistake to restrict the Division's autonomy in this matter, but he recommended to the Organizing Committee that the language requested by the Council be adopted, concluding that, “If at some later date the fears of the Council subside, the bylaws could be revised.” With that, he put the new draft of the bylaws to a vote by the Committee, requesting that ballots be returned by May 15, 1969. With the Division bylaws approved by the Organizing Committee, on May 16, 1969 Chamberlain distributed an invitation to join the Division to a list of “Initial Members, Division for Planetary Sciences, AAS.” Dues of $4.00 were to be sent to Owen. Just over 100 AAS members had expressed the desire to join the Division, plus “an additional dozen or so non-members” had indicated their intent to join the AAS and the Division. He urged all colleagues with an interest in the planetary sciences to affiliate with the DPS. On to San Francisco The success of the inaugural meeting of the DPS in Austin, especially its scientific symposium, led most of the active planetary scientists in the country to express interest in joining the Division. The approval by the AAS Council propelled Chamberlain and his Committee toward preparations for the First Annual Meeting, to be held in San Francisco in January, 1970. Chamberlain had invited Richard Goody to chair the scientific program in San Francisco. Goody accepted and enlisted the help of M. B. McElroy and Owen. Local arrangements for the San Francisco meeting were handled by George Pimentel and Hyron Spinrad. The meeting was held at the Jack Tar Hotel (since renamed) on January 19-21; the registration fee was $10. The program for Monday, January 19, consisted of a Symposium on Lunar Science, convened by W. Hess and W. Rubey, and a Symposium on Mars Imaging, convened by R. Leighton and T. B. McCord, followed by a Panel Discussion convened by H. Masursky. The next day began with a Symposium on the Atmosphere of Mars, convened by C. Leovy and M. McElroy, followed by the Annual Business Meeting (for DPS members only), and then a Symposium on Planetary Spectroscopy, convened by Owen and G. Münch. Wednesday, January 21, was occupied by 10-minute contributed papers, led off by Kuiper's paper on “Further High Altitude Spectra of Venus.” The minutes of the Business Meeting were kept by Owen. Present were Chamberlain, Anders, Pettengill, Kliore, Smith, Owen, Goody, McElroy, Sagan, Gurin, and guest L. LeMoine (KPNO). The minutes show that the main items of business concerned classes of membership and arrangements for the following annual meetings. Münch, B. Murray, and S. Gulkis were appointed to take charge of the 1971 meeting, with Owen's assistance. The results of the election of officers for 1970 were announced: Chamberlain was elected Chairman and Anders Vice-Chairman. “Committeemen” serving until 1971 were Sagan and I. Shapiro; until 1972, Kuiper and McElroy, and until 1973, Smith and Pettengill, thus establishing the cycle of staggered terms on the Committee. Dues were kept at $4 per year, and a change in the bylaws was proposed to clarify an ambiguity in electing the Secretary-Treasurer. Owen's Treasurer's report showed that dues had been received from 135 members, and with various mailing costs deducted, the Division's financial balance as of January 15, 1970 was $471.17. With the successful scientific meeting in San Francisco, and a Business Meeting that dealt primarily with mundane matters, the Division for Planetary Sciences was decisively launched. Looking ahead to the 1971 meeting, Chamberlain had already asked Anders to take on the program chairmanship to ensure avoidance of “any show of indecisiveness in San Francisco,” in part because “Sagan is starting to make noises again about being left out of things... .” Anders replied quickly, declining because of the “mess” that the lunar program had made of his life. “NASA is running it [the lunar program] like a military operation.” But Anders soon relented. Chamberlain's term as Chairman ended at the 1971 meeting in Tallahassee, when he turned the podium over to Anders as the incoming Chairman. Anders paid tribute to Chamberlain's years of effort on behalf of the DPS with a nautical metaphor: “Joe has helped launch the Good Ship DPS and, over the past two years, has steered its course through uncharted waters — some say in the wrong direction, but at least we're still afloat.” Figure 2. (l to r) Gerard P. Kuiper and Tobias Owen at the Texas radio telescope near Marfa circa 1970. Dale Cruikshank Photograph. Topics for Future Exploration The early years of the DPS were not without interesting incidents that could reasonably be attributed to the “growing pains” expected of any new organization. Some of these may merit a deeper historical study, using the materials in the archives of the DPS and the papers of some of the principals involved. Here we note just a few points of interest. A. Strife Over the Division Structure in the AAS Not long after the adoption of the Division structure in the AAS, discord arose between the divisions and the Council of the parent organization. On January 20, 1972, A. G. W. Cameron sent a four-page memorandum to all members of the Council of the AAS and all officers of the divisions. The memorandum began, “The American Astronomical Society, in its great wisdom, is promoting the fragmentation of astronomy into many non-communicating pieces.” The principal issues included the apparent indifference to the divisions on the part of the Council, and a lack of communication among the governing entities. The divisions were not usually represented at the meetings of the Council, the distribution of minutes of those meetings was not always reliable, and there were disputes over the costs incurred by the AAS in mailings that included divisional materials to the full membership. The strong tone of Cameron's memorandum sparked interest in the divisions and in the AAS Council to adopt policies For distribution of meeting minutes, payment for mailings, and inclusions of division materials in the Bulletin of the American Astronomical Society to help remedy the situation. Discussions on the issue of communication among the divisions and with the parent society continue to the present day. B. The Journal Icarus is Adopted by the DPS Carl Sagan became the Editor of Icarus beginning with Volume 10 in January 1969. At that time, Icarus was transformed from a journal in which papers were recommended for publication by one or two or three editors, to one in which submitted papers were fully refereed in what has become the standard method of operation for peer-reviewed scientific journals. A Publications Subcommittee, organized in 1971 and chaired by C. R. Chapman, began to discuss with Academic Press the establishment of a Divisional affiliation with Icarus in 1972 or 1973. With Sagan's encouragement, the DPS moved to adopt Icarus as the official journal of the Division, and starting with Volume 24, No. 1 January 1975), the cover of the journal bears the imprint, “Published in affiliation with the Division for Planetary Sciences, American Astronomical Society.” C. A Secessionist Movement in the DPS As the DPS membership grew in number and attracted scientists from non-astronomical disciplines (notably geology and meteorology), the relationship of the Division to the parent AAS was frequently questioned in the Committee and at the open Business Meetings. Non-astronomers reported treatment as second-class members, among other things. But of deeper concern, the DPS began to seek greater autonomy from the AAS in order to exert some political influence on the annual NASA budget that so strongly affected funding for planetary science. The discontent was relayed to AAS President E. M. Burbidge in January, 1977 in a letter from AAS Treasurer William E. Howard III, and in subsequent correspondence preserved in the DPS archives. Donald M. Hunten, the DPS Chairman for most of 1977, attended the Atlanta AAS meeting of the Council on June 11 of that year. He found that the Council clearly wanted to retain the affiliation of the planetary scientists with the AAS, and an agreement was reached by which the AAS would provide more support in the preparation of the program of the DPS annual meeting through the use of the BAAS. In order to give the Division more political flexibility, it was agreed that the DPS Chairman “may write letters as long as the AAS President is notified (or the Secretary in her absence).” As a consequence of this action by the Council and President Burbidge, the secessionist movement evaporated. Figure 3. Fred L. Whipple of the Smithsonian Astrophysical Observatory was the second winner of the G. P. Kuiper Prize of the DPS in 1985. Irwin photograph, August 1973. AIP Emilio Segrè Visual Archives, Irwin Collection. D. Establishing the DPS Prizes In 1973, DPS Secretary-Treasurer David Morrison, who served from 1971 to 1977, began to promote the idea of DPS Prizes to be awarded to meritorious planetary scientists, primarily to call attention to achievements in planetary science and to the professional activities of the Division. The concept met with mixed reactions. In a poll of the membership that Morrison conducted in 1973, he found that of 95 responding members, a small majority favored the prize. Of those who felt strongly about the issue, twice as many approved as disapproved. The matter was delayed, but Morrison later arranged for corporate funding of two prizes, which were finally instituted; in 1984, E. M. Shoemaker was the first recipient of the G. P. Kuiper prize, recognizing a lifetime of exceptional contributions to planetary science, and D. J. Stevenson received the first Harold C. Urey prize for outstanding contributions by a planetary scientist under the age of 36. The Harold Mazursky award for meritorious service to planetary science was first presented in 1991, to Carl Sagan. E. The DPS and the Press Most of the leadership of the DPS in the early years, and certainly the bulk of the membership at large, was inexperienced, uninformed, and somewhat naive about the promotion of planetary science in the press. Outreach to the public, who through their taxes pay for planetary science, was recognized as highly desirable, in part for the pure motive of education and in part for the delicate but practical reality of influencing public policy-making at the highest governmental levels. The DPS at its annual meetings sought to interest the press by issuing rather bland invitations to recognized science writers from a few national newspapers. This fundamentally passive approach had little effect. Jonathan Eberhart, the Space Sciences Editor of the weekly Science News, attended his first DPS meeting in 1974, in Palo Alto, California. At the next meeting, in 1975 in Columbia, Maryland, Eberhart was the only reporter present. He took an immediate liking to the DPS scientists and the meeting style, not to mention the windfall in new results to report in his weekly science magazine. In a long letter to Carl Sagan, Eberhart gave detailed and specific suggestions for improving and expanding the public awareness of planetary science. His suggestions were discussed among the DPS leadership, and most of them implemented, thus affecting the way in which the organization of the annual meetings interfaces with the press and local educators in the meeting city each year. At the Palo Alto meeting in 1991, the DPS honored Eberhart by arranging to have asteroid 4764 named Joneberhart, to recognize his contributions and loyalty to the Division. Figure 4. Joseph Wyan Chamberlain, circa 1960, taken at Kitt Peak. Photograph courtesy J. Chamberlain. A Note on Sources The letters and other documents referenced here are held in the Archives of the Division for Planetary Science housed at the Niels Bohr Library of the American Institute of Physics in College Park, Maryland. Copies of some of these materials will also be found in the professional papers of some of the principals mentioned in this chapter. Historical notes on the DPS, consisting of minutes of business meetings, lists of former officers, meetings, and prize recipients, are published with the abstracts from the Division's annual scientific meeting in the BAAS. - 1. R. E. Doel, Solar System Astronomy in America (Cambridge: Cambridge Universiy Press, 1996). - 2. J. N. Tatarewicz, Space Technology and Planetary Astronomy (Bloomington: Indiana University Press, 1990). - 3. G. P. Kuiper, in The Atmospheres of the Earth and Planets (Chicago: Univ. of Chicago Press, 2nd edition, 1952), p. v. - 4. G. P. Kuiper, ed., The Atmospheres of the Earth and Planets (Chicago: Univ. of Chcago Press, 2nd edition, 1952). - 5. D. P. Cruikshank, Biographical Memoirs of the National Academy of Sciences 62, 259-295, 1993. - 6. G. P. Kuiper, Communications of the Lunar and Planetary Laboratory 9, 183, 40J407, 1973. - 7. H. C. Urey, The Planets, their Origin and Development (New Haven: Yale Univ. Press, 1952). - 8. G. P. Kuiper, ed., The Sun (Chicago: Univ. of Chicago Press, 1953). - 9. G. P. Kuiper, ed., The Earth as a Planet (Chicago: Univ. of Chicago Press, 1954). - 10. A. Danjon, in The Earth as a Planet (Chicago Univ. of Chicago Press, 1953), pp. 726-738. - 11. J. W. Chamberlain, BAAS 21, 891-895 (1989). - 12. First Arizona Conference on Planetary Atmospheres, published in The Atmospheres of Venus and Mars, J. C. Brandt and M. B. McElroy, eds. (New York: Gordon and Breach Science Publ., Inc., 1968). - 13. “Second Arizona Conference on Planetary Atmospheres,” J. Atm. Sci. 25 (4), 533-671, 1968. - 14. “Third Arizona Conference on Planetary Atmospheres,” J. Atm. Sci. 26 (5), 795-1001, 1969. - 15. “Fourth Arizona Conference on Planetary Atmospheres,” Earth and Extraterrestrial Sciences 1, 171-184, 1970, and J. Atm. Sci. 27, 523-560, 1970. - 16. “Fifth Arizona Conference on Planetary Atmospheres,” J. Atm. Sci. 28, 833-1086, 1971. - 17. Planetary Astronomy, An Appraisal of Ground-Based Opportunities, Publication 1688, (National Academy of Sciences, 1968). The panel consisted of John S. Hall (Chair), J. W. Chamberlain, W. C. DeMarcus, R. Hide, G. P. Kuiper, B. Mason, C. H. Mayer, B. C. Murray, W. A. Noyes, Jr., J. Oro, T. C. Owen, G. H. Petengill, D. H. Rank, E. Roemer, and R. L. Wildey. W. E. Brunk and Urner Liddell were contributors from NASA, and N. W. Hinners served as a consultant. - 18. Owen to Chamberlain, 16 August 1985. - 19. Sagan and Owen memo, 1 February 1968. The memo was distributed to Edward Anders, Joseph W. Chamberlain, Frank D. Drake, George B. Field, John S. Hall, Seymour L. Hess, Norman Horowitz, Arvydas Kliore, Gerard P. Kuiper, Guido Mnch, John (Juan) Oro, Tobias Owen, Gordon H. Pettengill, Carl Sagan, Eugene M. Shoemaker, Harlan J. Smith, Rupert Wildt, and Albert G. Wilson. These individuals appeared on the “Tentative List of Members of Organizing Committee.” - 20. Draft letter to Whitford from Sagan and Owen, 1 February 1968. - 21. Anders to Sagan, 8 February 1968. - 22. Owen and Sagan to Whitford, 18 March 1968. - 23. Sagan and Owen cover letter, 21 March 1968. - 24. Whitford to Owen, 12 April 1968. - 25. Smith to Owen, 16 April 1968. Bracketed words in original. - 26. Owen and Sagan memo to distribution, 18 May 1968. Sent to people listed above under (19). - 27. Smith to Owen, 16 May 1968. - 28. McVittie to Chamberlain, 16 September 1968, with copies to Edward Anders, Lewis Branscomb, Richard Goody, John S. Hall, Arvydas Kliore, Michael McElroy, Tobias Owen, Gordon H. Pettengill, Carl Sagan, and Harlan J. Smith. - 29. Whitford to Chamberlain, approximately late 1985. - 30. Chamberlain to Organizing Committee, 17 September 1968. - 31. Chamberlain to long list of scientists, 1 October 1968. - 32. Anders to Chamberlain, 4 November 1968. - 33. Nominees for the Committee were R. Goody, G. Kuiper, M. McElroy, B. Murray, G. Pettengill, C. Sagan, I. Shapiro, H. Smith, and F. Whipple, Chamberlain to the Organizing Committee, 30 December 1968. - 34. Chamberlain to Organizing Committee, 30 December 1968. - 35. Chamberlain to Schwarzschild, 20 January 1969. - 36. Schwarzschild to Chamberlain, 19 February 1969. - 37. Chamberlain to Schwarzschild, 26 February 1969. - 38. Anders to Chamberlain, 11 March 1969. - 39. Anders to Chamberlain, 29 April 1969. - 40. Chamberlain to Organizing Committee, 24 April 1969. - 41. Chamberlain memorandum of invitation to join the DPS, 16 May 1969. - 42. Minutes of the first DPS Business meeting, by Owen, January, 1970. - 43. Chamberlain to Anders, 25 November 1969. - 44. Anders to Chamberlain, 1 December 1969. - 45. D. M. Hunten to Cruikshank, quoting from his notes made in 1977, 15 May 1997. - 46. Eberhart to Sagan, 2 April 1975. - 47. BAAS 28, 1175-1177, 1996. About the authors These paragraphs appeared at the end of The American Astronomical Society's first century volume. Joseph W. Chamberlain, emeritus professor in the Department of Space Physics and Astronomy at Rice University, was educated at the Universities of Missouri and Michgan. He was project scientist at the U.S. Air Force Cambridge Research Center (1951-1953) and was a staff member at the Yerkes Observatory from 1953 to 1962. He then was associate Director of the planetary science division of KPNO from 1962 to 1970. In 1971, he became adjunct professor at Rice and from 1971 to 1973 was Director or the Lunar Science Institute. His specialties include planetary atmospheres, aurora and airglow, as well as atmospheric pollution and climate. Dale P. Cruikshank is a planetary scientist at NASA's Ames Research Center. He received his B.S. from Iowa State University in 1961 and his Ph.D. from the University of Arizona in 1968. He has worked in Moscow and the Crimea, spent one more year at the Lunar and Planetary Laboratory, and in 1970 joined the faculty of the University of Hawaii. His specialty is asteroids and the small bodies of the outer Solar System. He is particularly interested in the organic material on small bodies, and the connections of such material with the organic matter and ices in the interstellar medium. He also studies the infrared spectra of asteroids, with the specific goal of tracing certain kinds of meteorites to their asteroidal parent bodies.

Below you’ll see that I’m running Mike Brown’s sketch of the ‘new’ Solar System, one I originally ran with our discussion of Joel Poncy’s Haumea orbiter paper, which was presented at Aosta in July. The sketch is germane on a slightly different level today because as we look at how our views of the Solar System have changed over the years, we’ve learned how many factors come into play, including one Brown’s sketch doesn’t show. For surrounding the planets and nearer regions of the Kuiper Belt is the heliosphere, that bubble of solar wind materials whose magnetic effects help protect the inner system. Image: Our view of the Solar System has gone from relatively straightforward to one of exceeding complexity. Credit: Mike Brown/Caltech. Look at the heliosphere diagram below and you’ll see that while the eight planets are comfortably within it, our Pioneers and Voyagers are pushing toward or through the termination shock on their way to the heliopause. Galactic cosmic rays are shown pushing from deep space in toward the bow shock. Our new view of the Solar System must include the fact that the heliosphere does not extend to all of it. The Oort Cloud, that vast sphere of comets, is well outside it, and so would be those Kuiper Belt objects that wander too far from the Sun. Image: Components of the heliosphere. Credit: NASA Ames. How about a future mission to Sedna? Better be careful, because this odd object moves out to about 990 AU at aphelion. Our intrepid astronauts, having solved the propulsion problem, would now face galactic cosmic rays without the helpful shielding effects of the heliosphere. Galactic cosmic rays are subatomic particles — protons and some heavy nuclei — that have been accelerated to high velocity by supernova explosions. They’re enough of a problem on the interplanetary level, but become even more of one beyond the system. All this comes to mind because we’re seeing an increase in cosmic ray intensities, some 19 percent higher than what we’ve seen in the last fifty years, according to Caltech’s Richard Mewaldt, who adds “The increase is significant, and it could mean we need to re-think how much radiation shielding astronauts take with them on deep-space missions.” This NASA news release points to three culprits: a flagging solar wind, a decline in the Sun’s interplanetary magnetic field, and a flattening of the heliospheric current sheet where the polarity of the Sun’s magnetic field changes from a plus to a minus. We’re safe enough where we are, of course, because the Earth’s atmosphere has allowed life to weather far worse cosmic ray fluxes. But if Mewaldt is right, we may have experienced a low level of cosmic ray activity for most of the space era. “We may now be returning to levels typical of past centuries,” says the scientist, reminding us how much we have to learn about the factors that make space flight within and without the system a hazardous enterprise.

The Moon in 3-D Pictorial representation of the ARTEMIS probes as they will orbit the moon beginning July 17. ARTEMIS P1 and P2 were the outermost two THEMIS probes before they began maneuvers on July 20, 2009, to swap an Earth orbit for a lunar orbit. Credit: UC Berkeley On Sunday, July 17, the Moon will acquire its second new companion in less than a month. That’s when the second of two probes built by the University of California, Berkeley, and part of NASA’s five-satellite THEMIS mission will drop into a permanent lunar orbit after a meandering, two-year journey from its original orbit around Earth. The first of the two probes settled into a stable orbit around the Moon’s equator on June 27. If all goes well, the second probe will assume a similar lunar orbit, though in the opposite direction, sometime Sunday afternoon. The two spacecraft that comprise the ARTEMIS mission will immediately begin the first observations ever conducted by a pair of satellites of the lunar surface, its magnetic field and the surrounding magnetic environment. "With two spacecraft orbiting in opposite directions, we can acquire a full 3-D view of the structure of the magnetic fields near the Moon and on the lunar surface," said Vassilis Angelopoulos, principal investigator for the THEMIS and ARTEMIS missions and a professor of space physics at UCLA. "ARTEMIS will be doing totally new science, as well as reusing existing spacecraft to save a lot of taxpayer money." "These are the most fully equipped spacecraft that have ever gone to the Moon," added David Sibeck, THEMIS and ARTEMIS project scientist at the Goddard Space Flight Center (GSFC) in Maryland. "For the first time we’re getting a unique, two-point perspective of the Moon from two spacecraft, and that will be a major component of our overall lunar research program." The transition into a lunar orbit will be handled by engineers at UC Berkeley’s Space Sciences Laboratory (SSL), which serves as mission control both for THEMIS (Time History of Events and Macroscale Interactions during Substorms) and ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun). "We are on our way," said Manfred Bester, SSL director of operations. "We’re committed." What makes the auroras dance? Artist’s concept of THEMIS in orbit. THEMIS was a 2-year mission consisting of 5 identical probes designed to study the violent eruptions of Auroras. Credit: NASA The five THEMIS satellites (or probes) were launched by NASA on Feb. 17, 2007 to explore how the Sun’s magnetic field and million-mile-per-hour solar wind interact with Earth‘s magnetic field on Earth’s leeward side, opposite the Sun. Within a year and a half, they had answered the mission’s primary question: Where and how do substorms in the Earth’s magnetosphere – which make the auroras at the north and south poles dance – originate? The answer: the storms originate deep in the planet’s shadow, about a third of the way to the Moon, where magnetic field lines snap, reconnect and unleash a storm of energy that funnels to the poles and makes the atmosphere glow in reds and greens. Large storms can wreak havoc on satellites, power grids and communications systems. Mission accomplished, the THEMIS team was eager to divert two of the probes to the Moon to extend their magnetic field studies farther into space. One key reason was that the two probes most distant from Earth would soon die because, with too much time spent in Earth’s shadow, their solar-powered batteries would discharge. To achieve this new mission, the UC Berkeley and Goddard teams, with the assistance of experts at the Jet Propulsion Laboratory in Pasadena, charted the 150 fuel-saving orbital maneuvers needed to boost the two THEMIS spacecraft from Earth’s orbit into temporary orbits around the two Earth-Moon Lagrange points, which are spots in space where the gravitational attraction from the Moon and Earth are equal. That transfer took about 18 months, after which Goddard colleagues kept the two spacecraft in Lagrange-point orbits for several months before the first probe (P1) was transferred into lunar orbit last month. "That was an engineering challenge; this is the first mission where we’ve piloted into a lunar orbit spacecraft not designed to go there," said Daniel Cosgrove, the UC Berkeley engineer who controls the spacecrafts’ trajectories. The probes’ small thrusters, for example, only push down and sideways. The probes are also spinning, which makes maneuvering even more difficult. Also, last year probe P1 lost a spherical sensor from the end of one of four long wires that protrude from the spacecraft to measure electrical fields in space. The probable cause was a micrometeorite that cut a 10-foot section off of the 82-foot wire and caused it to retract into its original spherical housing, sending the "little black sphere flying through the Solar System," Bester said. "All five spacecraft have been built by a very talented team with enormous attention to detail," he said, predicting that the ARTEMIS probes could survive for another 10 years, longer than the three remaining THEMIS probes, which repeatedly fly in and out of Earth’s dangerous Van Allen radiation belt. Side view of the ARTEMIS P1 probe’s orbit in 2010 as it cruised around the two Earth-moon Lagrange points. In 2011 it maneuvered into a permanent orbit around the Moon. Credit: NASA Once the second probe, P2, is in orbit, the two ARTEMIS satellites will graze the lunar surface once per orbit – approaching within a few tens of kilometers – in a belt ranging 20 degrees above and below the equator while recording electric and magnetic fields and ion concentrations. "When the Moon traverses the solar wind, the magnetic field embedded in the rocks near the surface interacts with the solar wind magnetic field, while the surface itself absorbs the solar wind particles, creating a cavity behind the Moon," Angelopoulos said. "We can study these complex interactions to learn much about the Moon as well as the solar wind itself from a unique two-point vantage that reveals for the first time 3-D structures and dynamics." Sibeck noted that NASA’s twin STEREO spacecraft, launched in 2006, already provide a 3-D perspective on the sun’s large-scale magnetic fields. "THEMIS and ARTEMIS study the microscale processes, which we now know run the system," he said. One goal of the ARTEMIS mission is to look for plasmoids, which are hot blobs of ionized gas or plasma. "THEMIS found evidence that magnetic reconnection propels hot blobs of plasma both towards and away from the Earth, and we want to find out how big they are and how much energy they carry," Angelopoulos said. "Plasmoids could be tens of thousands of kilometers across." "THEMIS found the cause and now ARTEMIS will study the consequences, which are likely massive and global," Sibeck said. The spacecraft also will study the surface composition of the Moon by recording the solar wind particles reflected or scattered from the surface and the ions sputtered out of the surface by the wind. "These measurements can tell us about the properties of the surface, from which we can infer the formation and evolution of the surface over billions of years," Angelopoulos said. The two ARTEMIS probes will join NASA’s Lunar Reconnaissance Orbiter, which has been orbiting the Moon since 2009 taking high-resolution photographs and looking for signs of water ice. In September, NASA is scheduled to launch two GRAIL (Gravity Recovery and Interior Laboratory) spacecraft to map the Moon’s gravitational field, and in 2013, the agency plans to launch LADEE (Lunar Atmosphere and Dust Environment Explorer) to characterize the lunar atmosphere and dust environment. "ARTEMIS will provide context for the LADEE mission," Sibeck said. Three other non-functioning satellites remain in orbit around the Moon: two subsatellites of Japan’s lunar orbiter, Kaguya, which was guided to a crash on the surface in 2009; and India’s Chandrayaan-1, which lost communication with Earth that same year. China’s second lunar orbiter, Chang’e 2, left the Moon for interplanetary space on June 8.

How to Create a Colour Saturated Moon Photo Submitted: Friday, 16th September 2011 by Mike Salway Why does the picture of the Moon above have those funky colours? You can't see them with your eyes, or through the telescope like that, right? Actually the colours are real - they've just been artificially boosted; amplified during processing. The colours themselves represent the various types of iron and mineral deposits on the Moon. The blue hues reveal titanium rich areas while orange and purple colors show regions relatively poor in titanium and iron. In this article, I'm going to show you how to process your lunar images to bring out those colours. I'll talk a little about the equipment and capture, but most of the article will focus on the image processing. Equipment and Capture For my images, I used a standard Saxon ED80 with a modded Canon 40D DSLR. You can use almost anything though - the telescope can be your newtonian, to your SCT or refractor or even a long telephoto lens. Your capture device can be a DSLR, dedicated astro camera or webcam. However there are a couple of points to consider. Your telescope, any extensions/barlows and the camera will dictate the focal length and therefore the image scale of the Moon when captured on the device. With a standard DSLR, a focal length of around 1000mm will fit the Full Moon in the Field of View (FOV). Any longer focal length, and you won't fit the whole Moon on the chip. You'll need to capture the parts of the Moon separately and do a mosaic to create a Full Moon image. If your focal length is too short (500mm and under), the Moon will be quite small on the DSLR chip - so when you crop the image around the Moon, you won't get the same sharpness and detail at full resolution. If you're using a webcam, the chip is much smaller and the resolution is much smaller too. It will depend on the focal length of your telescope, but you might end up with a much more "zoomed in" view and capture only a portion of the Moon. If you're using a Newtonian, your DSLR may not come to focus at prime focus unless you move the mirror up the tube. You'll have to experiment yourself - this article isn't focusing on the capture part of the process. My Saxon ED80 only has a 600mm focal length, so I used part of a 2x barlow and an extension tube (necessary to bring it to focus) to reach around 1000mm. The Moon just fits in the field of view of my 40D, but it depends whether the Moon is at apogee or perigee. I capture a mosaic anyway - see below for more. Capture Device (Camera) Any camera will work, but it obviously has to be a colour camera. A monochrome camera obviously cannot capture colour :) In my opinion, a DSLR is best for this type of job. Good size colour chip, good resolution for printing later, easy to capture onto the computer via remote control. With my setup, the Moon doesn't always fit in the FOV of the DSLR so I capture the Moon in 2 parts - the top half, and then the bottom half. I obviously have a large amount of overlap. I connect the DSLR to my laptop and use the standard EOS Utility Remote Shooting to remote control my camera. For my images, I use ISO250 and 1/60s exposure and the histogram was comfortably in the top third towards white without blowing out any highlights. I captured 60-70 images for the top half and the same for the bottom half. Take them as quickly in succession as possible and try not to let the Moon drift too much during your sequence, or Registax might have trouble aligning. The reason for capturing so many images is so that you can stack them using Registax. This reduces noise in your images and they'll be less grainy when you push the sharpening and colour saturation. You can do it with a single image, however in most cases it just won't end up as smooth. The images were captured in RAW format, so I need to convert them to TIF to load into Registax. I use Lightroom for this - for no other reason than it's my pre-processing software of choice. All I do is simply export all images as TIF. You can see in the image below how I capture the top half and bottom half of the Moon. The pink tinge to the images is because the camera is a modded DSLR. Like I said above, the reason we stack multiple images together is to increase signal and reduce the noise. I use Registax for this, however you may prefer to try other DSLR image stacking programs like ImagesPlus or other. I actually had some difficulties with Registax. The latest version (v6) just doesn't work for me with these large images. I ended up using Registax 5.1 with a single alignment point. You can experiment with what works best for your images on your computer - but the end result is you want to stack the sharpest of your images, and apply some wavelets to the stacked image. I stacked the sharpest 30-35 frames, and produced 2 versions - a "harder" wavelets version which brought out more detail, and a "softer" wavelets version that I use for the very edge of the Moon. You'll see shortly why I do this. I saved each version as a TIF. Don't forget I repeat this process for both the top half and bottom half of the Moon - I haven't joined them yet. Merging / Mosaic I'm now ready to join my Moon Halves into a Full Moon. I've got 4 images now: I use AutoPano Pro to do any stitching/mosaic work. It's just simply the best program around and works exceptionally well. The normal workflow in AutoPano Pro: It's that easy. I've never had a time when it couldn't stitch my mosaics together. Processing in Photoshop Now for the fun part. Everything we've done so far is just to get a sharpened Full Moon image into Photoshop so we can bring out the colour! Fixing the Limb You should now have 2 images - a stitched "hard wavelets" version, and a stitched "soft wavelets" version. The reason I process two versions, is because when you use harder wavelets, it can be quite harsh on the edges of very contrasty areas - especially the limb of the Moon. It creates a hard white edge that can make it look overprocessed. So I copy the outer few pixels of the "soft wavelets" version, and paste them over the top of the "hard wavelets" version to make the limb look less processed. The process I use to do this is: Switch to the "hard" image You can see the effect in the image below; the right part of the image shows the limb with the soft layer switched off. You can see how there's a hard white edge that looks pretty ugly. The left part of the image shows the soft layer switched on. It's much softer and more natural looking around the limb. Fixing Colour Balance You can see from the images above that the Moon has a very pink colour cast - the reason for this is because I was using my modded Canon 40D for these images, which gives a pink tinge to all the images as its capturing more into the infrared part of the spectrum. You can see from the image below how pink it is, and how mismatched the histogram is with the colour channels all over the place. So we need to fix that. To fix it, use Photoshop's fabulous Auto Colour correction. Check the result below - excellent! Contrast Using Levels and Curves I love a more contrasty look on the Moon, highlighting the differences between the mare and the highlands. So I use Levels and Curves to increase the contrast. There's no general "rule" for how much to apply here - it's purely personal taste and what type of image you want. Again, just keep an eye on your histogram and make sure you're not blowing out the highlights and mainly just adjusting the black points and mid levels. You can see the more contrasty image and my new histogram below, after using levels and curves adjustment layers as shown on the image. Copy your adjustments into a new layer, same as before. This gives us a new base layer. Now it's time to do some noise reduction, and I use the awesome Topaz De-Noise plugin for this (the whole set of Topaz plugins are very useful). Duplicate the layer (Ctrl-J), and on the new layer, go to Topaz De-Noise. I use the "RAW Moderate" preset, but it will depend on your camera and how noisy the image is to begin with, and again you can use your personal taste and preference for how smooth you want the final result. The reason I duplicate the layer is so you can use the opacity of the layer to back off the adjustments if you think it looks a bit over-smoothed. In this case I didn't. Now the fun part - enhancing the colour! This is done by using a Saturation adjustment layer, and it can be as simple as a single layer and pushing the saturation hard - but it can look quite harsh and technicolour, as you can see from the image below. Instead, we only use minor amounts of Saturation adjustment (I use 13) and then duplicate the layers until you get the level of saturation and colour you're after. Again, it's personal taste but I usually use about 7 or 8 duplicated layers to get to where I'm generally happy. The image below shows this result. Start by merging the image so far into a new layer, by Ctrl-A, Ctrl-Shift-C, and then Ctrl-V to paste as a new layer. Then, go down and select your "after noise adjustment" layer, and duplicate it (Ctrl-J), and move it right to the top so it's at the top of your layer stack. Change the layer blending mode to "Luminosity". What this has now done, is to use the Detail from your Pre-Colourised Data, and use the Colour Data from the merged layer beneath. We can now do adjustments to the colour without affecting the sharpness, and vice versa. By using the luminance from your earlier layers, you won't get the colour noise from the saturation adjustments in your final image. Sometimes the effect is minor, but it depends on your adjustments and what other adjustments or sharpening you might do. See the screenshot for the example, hopefully it'll make more sense. I might sometimes do some final adjustments (personal taste) to Colour Balance or Curves, and I can do this between the merged saturation layer, and my luminosity layer, or applied to the whole image. You can see in the image above I've done a couple more adjustments to get the image how I like it. Saving for Later I still need to do some final web or print preparation, but you'll want to save a version with all of your layers still in case you want to modify the image later. I call my file something like "moon-working.psd". Adding Text and Web Preparation The hard work is now done. I flatten the image (Layer->Flatten Image), and save as a new filename, "moon-flat.psd". I can now do any final touches such as: The image below you can see the flattened image with a text layer added. Want a Less Saturated Version? Not everyone wants a highly saturated version - that's no problem. It's easy to create a less saturated version with all the same adjustments. If you want it pure black and white, you can always change the image to greyscale (Image->Mode->Greyscale) instead of RGB. In the image below you can see a version that has been flattened, and a new de-saturation layer added where I mostly de-saturate the image. Again, it's personal taste. What I have presented has been my workflow - there are always many ways to achieve the same or a similar result, and your mileage may vary. This tutorial should be used as a guide rather than verbatim; your image may not respond well to the same adjustments, depending on the telescope and camera used. I sincerely hope that it does inspire you to give it a go, and I hope you try and improve your skills in image capture and processing. I look forward to seeing your attempts in the IceInSpace Solar System Forum. Larger versions of my final saturated and de-saturated Moon images are posted on my blog at: Colour Full Moon, September 2011.

'Ageless' silicon throughout Milky Way may indicate a well-mixed galaxy As galaxies age, some of their basic chemical elements can also show signs of aging. This aging process can be seen as certain atoms "put on a little weight," meaning they change into heavier isotopes—atoms with additional neutrons in their nuclei. Surprisingly, new surveys of the Milky Way with the National Science Foundation's (NSF) Green Bank Telescope (GBT) in West Virginia, found no such aging trend for the element silicon, a fundamental building block of rocks throughout our solar system. This "ageless" appearance may mean that the Milky Way is more efficient at mixing its contents than previously thought, thereby masking the telltale signs of chemical aging. When massive first-generation stars in young galaxies end their lives as violent supernovas, they fill the cosmos with so-called primary isotopes—elements like oxygen, carbon, and silicon with a balance of neutrons and protons in their nuclei. "Massive stars are the cauldrons in which heavy elements like silicon are fabricated," said Ed Young, a scientist at the University of California at Los Angeles and author on a study appearing in the Astrophysical Journal. "First-generation stars make silicon 28—an isotope with 14 protons and 14 neutrons in its nucleus. Over billions of years, later generations of stars are able to create the heavier silicon 29 and 30 isotopes. When these later-generation stars explode as supernovas, the heavier isotopes are blasted into the interstellar medium, subtly altering the chemical profile of the galaxy." Astronomers cannot directly measure these long-term chemical changes. They can, however, do the next best thing: measuring the apparent maturing of isotopes from the outskirts of our galaxy toward its center. Since there is a greater concentration of stars the closer you get to the center of the Milky Way, including massive stars that end of their lives as supernovas, astronomers expect to find a greater percentage of heavier isotopes among the elements there. Past radio telescope studies of carbon and oxygen atoms in the Milky Way provided some indication that there is in fact a steady progression from light to heavy isotopes the closer you move toward the galactic center. Intervening interstellar clouds, however, made these observations difficult and the results were inconclusive. "There were some tantalizing hints in past studies that carbon and oxygen isotope ratios shifted as expected. But it was difficult to account for the material in the interstellar medium, so we were uncertain how reliable these data were," said Young. "Silicon, as detected in molecules of silicon monoxide, has a spectral signature that makes it much easier to account for the dust and gas in our galaxy. We therefore had to make fewer assumptions than were necessary for the surveys done for oxygen and carbon." Using the 100-meter GBT, the astronomers surveyed vast swaths of the Milky Way, starting from the region near our sun and then moving all the way toward the galactic center. In each region, they probed the radio spectra naturally emitted by silicon monoxide molecules. Differences in the silicon isotopes would be seen as subtle changes in the radio spectra. Counter to their expectations, the researchers found none of the expected gradient in the isotope ratios. "There was no evidence of a gradient," said Nathaniel Monson, a member of the research team and a graduate student at UCLA. "That was a bit surprising. We may have to reassess what we think we know about our galaxy." These data may mean that the Milky Way is remarkably efficient at mixing its material, circulating molecules and atoms from the galactic center out into the galaxy's spiral arms and back. It is also possible that type 1a supernovas—which are formed in binary systems when a white dwarf star steals too much material from its companion and detonates—produce an overabundance of Si 28 later in the lifespan of a galaxy. If subsequent surveys of carbon and oxygen are better able to account for past uncertainties and show the same lack of gradient, it would point to mixing as being the most likely scenario. "There's a lot about the galaxy we don't understand yet," concluded Young. "It's possible that further studies with the GBT will teach us a bit more about the Milky Way."

Our editors will review what you’ve submitted and determine whether to revise the article.Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work! Bernard Lyot, (born Feb. 27, 1897, Paris, Fr.—died April 2, 1952, Cairo, Egypt), French astronomer who invented the coronagraph (1930), an instrument which allows the observation of the solar corona when the Sun is not in eclipse. Before Lyot’s coronagraph, observing the corona had been possible only during a solar eclipse, but this was unsatisfactory because total eclipses occur only rarely and the duration of such eclipses is too short (no more than seven minutes) to allow prolonged scientific observation of the corona. Merely blocking out the Sun’s radiant disk was insufficient to view the comparatively dim corona because of the diffusion of the Sun’s light by the atmosphere, whose brightness rendered the delicate corona invisible. But by going to the Pic du Midi Observatory high in the French Pyrenees, where the high altitude resulted in less atmospheric diffusion, and by equipping his coronagraph with an improved lens and a monochromatic filter that he had developed, Lyot succeeded in making daily photographs of the Sun’s corona. In 1939, using his coronagraph and filters, he shot the first motion pictures of the solar prominences. Learn More in these related Britannica articles: telescope: Solar telescopesBernard Lyot constructed another type of solar telescope in 1930 at Pic du Midi Observatory in France. This instrument was specifically designed for photographing the Sun’s corona (the outer layer), which up to that time had been successfully photographed only during solar eclipses. The coronagraph,… coronagraph…1930 by the French astronomer Bernard Lyot and was used to observe the Sun’s corona and prominences.… Corona, outermost region of the Sun’s atmosphere, consisting of plasma (hot ionized gas). It has a temperature of approximately two million kelvins and an extremely low density. The corona continually varies in size and shape as it is affected by the Sun’s magnetic field. The solar wind, which flows radially…

In chemistry an element is a species of atom having the same number of protons in its atomic nuclei (that is, the same atomic number, or Z). For example, the atomic number of oxygen is 8, so the element oxygen describes all atoms which have 8 protons. In total, 118 elements have been identified. The first 94 occur naturally on Earth, and the remaining 24 are synthetic elements. There are 80 elements that have at least one stable isotope and 38 that have exclusively radionuclides, which decay over time into other elements. Iron is the most abundant element (by mass) making up Earth, while oxygen is the most common element in the Earth's crust. Chemical elements constitute all of the ordinary matter of the universe. However, astronomical observations suggest that ordinary observable matter makes up only about 15% of the matter in the universe. The remainder is dark matter; the composition of this is unknown, but it is not composed of chemical elements. The two lightest elements, hydrogen and helium, were mostly formed in the Big Bang and are the most common elements in the universe. The next three elements (lithium, beryllium and boron) were formed mostly by cosmic ray spallation and are thus rarer than heavier elements. Formation of elements with 6 to 26 protons occurs in main sequence stars via stellar nucleosynthesis. The high abundance of oxygen, silicon, and iron on Earth reflects their common production in such stars. Elements with greater than 26 protons are formed by nucleosynthesis in supernovae, which, when they explode, blast these elements as supernova remnants far into space, where they may become incorporated into planets when they are formed. The term "element" is used for atoms with a given number of protons (regardless of whether or not they are ionized or chemically bonded, e.g. hydrogen in water) as well as for a pure chemical substance consisting of a single element (e.g. hydrogen gas). For the second meaning, the terms "elementary substance" and "simple substance" have been suggested, but they have not gained much acceptance in English chemical literature, whereas in some other languages their equivalent is widely used (e.g. French corps simple, Russian простое вещество). A single element can form multiple substances differing in their structure; they are called allotropes of the element. When different elements are chemically combined, with the atoms held together by chemical bonds, they form chemical compounds. Only a minority of elements are found uncombined as relatively pure minerals. Among the more common of such native elements are copper, silver, gold, carbon (as coal, graphite, or diamonds), and sulfur. All but a few of the most inert elements, such as noble gases and noble metals, are usually found on Earth in chemically combined form, as chemical compounds. While about 32 of the chemical elements occur on Earth in native uncombined forms, most of these occur as mixtures. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, and native solid elements occur in alloys, such as that of iron and nickel. The history of the discovery and use of the elements began with primitive human societies that found native elements like carbon, sulfur, copper and gold (though the status of these materials as elements was not known at the time). Later civilizations extracted elemental copper, tin, lead and iron from their ores by smelting, using charcoal. Alchemists and chemists subsequently identified many more; all of the naturally occurring elements were known by 1950. The properties of the chemical elements are summarized in the periodic table, which organizes the elements by increasing atomic number into rows ("periods") in which the columns ("groups") share recurring ("periodic") physical and chemical properties. Save for unstable radioactive elements with short half-lives, all of the elements are available industrially, most of them in low degrees of impurities. The lightest chemical elements are hydrogen and helium, both created by Big Bang nucleosynthesis during the first 20 minutes of the universe in a ratio of around 3:1 by mass (or 12:1 by number of atoms), along with tiny traces of the next two elements, lithium and beryllium. Almost all other elements found in nature were made by various natural methods of nucleosynthesis. On Earth, small amounts of new atoms are naturally produced in nucleogenic reactions, or in cosmogenic processes, such as cosmic ray spallation. New atoms are also naturally produced on Earth as radiogenic daughter isotopes of ongoing radioactive decay processes such as alpha decay, beta decay, spontaneous fission, cluster decay, and other rarer modes of decay. Of the 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope (except for technetium, element 43 and promethium, element 61, which have no stable isotopes). Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected. Some of these elements, notably bismuth (atomic number 83), thorium (atomic number 90), and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy metals before the formation of our Solar System. At over 1.9×1019 years, over a billion times longer than the current estimated age of the universe, bismuth-209 (atomic number 83) has the longest known alpha decay half-life of any naturally occurring element, and is almost always considered on par with the 80 stable elements. The very heaviest elements (those beyond plutonium, element 94) undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized. As of 2010, there are 118 known elements (in this context, "known" means observed well enough, even from just a few decay products, to have been differentiated from other elements). Of these 118 elements, 94 occur naturally on Earth. Six of these occur in extreme trace quantities: technetium, atomic number 43; promethium, number 61; astatine, number 85; francium, number 87; neptunium, number 93; and plutonium, number 94. These 94 elements have been detected in the universe at large, in the spectra of stars and also supernovae, where short-lived radioactive elements are newly being made. The first 94 elements have been detected directly on Earth as primordial nuclides present from the formation of the solar system, or as naturally occurring fission or transmutation products of uranium and thorium. The remaining 24 heavier elements, not found today either on Earth or in astronomical spectra, have been produced artificially: these are all radioactive, with very short half-lives; if any atoms of these elements were present at the formation of Earth, they are extremely likely, to the point of certainty, to have already decayed, and if present in novae have been in quantities too small to have been noted. Technetium was the first purportedly non-naturally occurring element synthesized, in 1937, although trace amounts of technetium have since been found in nature (and also the element may have been discovered naturally in 1925). This pattern of artificial production and later natural discovery has been repeated with several other radioactive naturally occurring rare elements. List of the elements are available by name, atomic number, density, melting point, boiling point and by symbol, as well as ionization energies of the elements. The nuclides of stable and radioactive elements are also available as a list of nuclides, sorted by length of half-life for those that are unstable. One of the most convenient, and certainly the most traditional presentation of the elements, is in the form of the periodic table, which groups together elements with similar chemical properties (and usually also similar electronic structures). The atomic number of an element is equal to the number of protons in each atom, and defines the element. For example, all carbon atoms contain 6 protons in their atomic nucleus; so the atomic number of carbon is 6. Carbon atoms may have different numbers of neutrons; atoms of the same element having different numbers of neutrons are known as isotopes of the element. The number of protons in the atomic nucleus also determines its electric charge, which in turn determines the number of electrons of the atom in its non-ionized state. The electrons are placed into atomic orbitals that determine the atom's various chemical properties. The number of neutrons in a nucleus usually has very little effect on an element's chemical properties (except in the case of hydrogen and deuterium). Thus, all carbon isotopes have nearly identical chemical properties because they all have six protons and six electrons, even though carbon atoms may, for example, have 6 or 8 neutrons. That is why the atomic number, rather than mass number or atomic weight, is considered the identifying characteristic of a chemical element. The symbol for atomic number is Z. Isotopes are atoms of the same element (that is, with the same number of protons in their atomic nucleus), but having different numbers of neutrons. Thus, for example, there are three main isotopes of carbon. All carbon atoms have 6 protons in the nucleus, but they can have either 6, 7, or 8 neutrons. Since the mass numbers of these are 12, 13 and 14 respectively, the three isotopes of carbon are known as carbon-12, carbon-13, and carbon-14, often abbreviated to 12C, 13C, and 14C. Carbon in everyday life and in chemistry is a mixture of 12C (about 98.9%), 13C (about 1.1%) and about 1 atom per trillion of 14C. Most (66 of 94) naturally occurring elements have more than one stable isotope. Except for the isotopes of hydrogen (which differ greatly from each other in relative mass—enough to cause chemical effects), the isotopes of a given element are chemically nearly indistinguishable. All of the elements have some isotopes that are radioactive (radioisotopes), although not all of these radioisotopes occur naturally. The radioisotopes typically decay into other elements upon radiating an alpha or beta particle. If an element has isotopes that are not radioactive, these are termed "stable" isotopes. All of the known stable isotopes occur naturally (see primordial isotope). The many radioisotopes that are not found in nature have been characterized after being artificially made. Certain elements have no stable isotopes and are composed only of radioactive isotopes: specifically the elements without any stable isotopes are technetium (atomic number 43), promethium (atomic number 61), and all observed elements with atomic numbers greater than 82. Of the 80 elements with at least one stable isotope, 26 have only one single stable isotope. The mean number of stable isotopes for the 80 stable elements is 3.1 stable isotopes per element. The largest number of stable isotopes that occur for a single element is 10 (for tin, element 50). The mass number of an element, A, is the number of nucleons (protons and neutrons) in the atomic nucleus. Different isotopes of a given element are distinguished by their mass numbers, which are conventionally written as a superscript on the left hand side of the atomic symbol (e.g. 238U). The mass number is always a whole number and has units of "nucleons". For example, magnesium-24 (24 is the mass number) is an atom with 24 nucleons (12 protons and 12 neutrons). Whereas the mass number simply counts the total number of neutrons and protons and is thus a natural (or whole) number, the atomic mass of a single atom is a real number giving the mass of a particular isotope (or "nuclide") of the element, expressed in atomic mass units (symbol: u). In general, the mass number of a given nuclide differs in value slightly from its atomic mass, since the mass of each proton and neutron is not exactly 1 u; since the electrons contribute a lesser share to the atomic mass as neutron number exceeds proton number; and (finally) because of the nuclear binding energy. For example, the atomic mass of chlorine-35 to five significant digits is 34.969 u and that of chlorine-37 is 36.966 u. However, the atomic mass in u of each isotope is quite close to its simple mass number (always within 1%). The only isotope whose atomic mass is exactly a natural number is 12C, which by definition has a mass of exactly 12 because u is defined as 1/12 of the mass of a free neutral carbon-12 atom in the ground state. The standard atomic weight (commonly called "atomic weight") of an element is the average of the atomic masses of all the chemical element's isotopes as found in a particular environment, weighted by isotopic abundance, relative to the atomic mass unit. This number may be a fraction that is not close to a whole number. For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than 1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are naturally present in a sample of that element. Chemists and nuclear scientists have different definitions of a pure element. In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the same atomic number, or number of protons. Nuclear scientists, however, define a pure element as one that consists of only one stable isotope. For example, a copper wire is 99.99% chemically pure if 99.99% of its atoms are copper, with 29 protons each. However it is not isotopically pure since ordinary copper consists of two stable isotopes, 69% 63Cu and 31% 65Cu, with different numbers of neutrons. However, a pure gold ingot would be both chemically and isotopically pure, since ordinary gold consists only of one isotope, 197Au. Atoms of chemically pure elements may bond to each other chemically in more than one way, allowing the pure element to exist in multiple chemical structures (spatial arrangements of atoms), known as allotropes, which differ in their properties. For example, carbon can be found as diamond, which has a tetrahedral structure around each carbon atom; graphite, which has layers of carbon atoms with a hexagonal structure stacked on top of each other; graphene, which is a single layer of graphite that is very strong; fullerenes, which have nearly spherical shapes; and carbon nanotubes, which are tubes with a hexagonal structure (even these may differ from each other in electrical properties). The ability of an element to exist in one of many structural forms is known as 'allotropy'. The standard state, also known as the reference state, of an element is defined as its thermodynamically most stable state at a pressure of 1 bar and a given temperature (typically at 298.15 K). In thermochemistry, an element is defined to have an enthalpy of formation of zero in its standard state. For example, the reference state for carbon is graphite, because the structure of graphite is more stable than that of the other allotropes. Several kinds of descriptive categorizations can be applied broadly to the elements, including consideration of their general physical and chemical properties, their states of matter under familiar conditions, their melting and boiling points, their densities, their crystal structures as solids, and their origins. Several terms are commonly used to characterize the general physical and chemical properties of the chemical elements. A first distinction is between metals, which readily conduct electricity, nonmetals, which do not, and a small group, (the metalloids), having intermediate properties and often behaving as semiconductors. A more refined classification is often shown in colored presentations of the periodic table. This system restricts the terms "metal" and "nonmetal" to only certain of the more broadly defined metals and nonmetals, adding additional terms for certain sets of the more broadly viewed metals and nonmetals. The version of this classification used in the periodic tables presented here includes: actinides, alkali metals, alkaline earth metals, halogens, lanthanides, transition metals, post-transition metals, metalloids, reactive nonmetals, and noble gases. In this system, the alkali metals, alkaline earth metals, and transition metals, as well as the lanthanides and the actinides, are special groups of the metals viewed in a broader sense. Similarly, the reactive nonmetals and the noble gases are nonmetals viewed in the broader sense. In some presentations, the halogens are not distinguished, with astatine identified as a metalloid and the others identified as nonmetals. Another commonly used basic distinction among the elements is their state of matter (phase), whether solid, liquid, or gas, at a selected standard temperature and pressure (STP). Most of the elements are solids at conventional temperatures and atmospheric pressure, while several are gases. Only bromine and mercury are liquids at 0 degrees Celsius (32 degrees Fahrenheit) and normal atmospheric pressure; caesium and gallium are solids at that temperature, but melt at 28.4 °C (83.2 °F) and 29.8 °C (85.6 °F), respectively. Melting and boiling points, typically expressed in degrees Celsius at a pressure of one atmosphere, are commonly used in characterizing the various elements. While known for most elements, either or both of these measurements is still undetermined for some of the radioactive elements available in only tiny quantities. Since helium remains a liquid even at absolute zero at atmospheric pressure, it has only a boiling point, and not a melting point, in conventional presentations. The density at selected standard temperature and pressure (STP) is frequently used in characterizing the elements. Density is often expressed in grams per cubic centimeter (g/cm3). Since several elements are gases at commonly encountered temperatures, their densities are usually stated for their gaseous forms; when liquefied or solidified, the gaseous elements have densities similar to those of the other elements. When an element has allotropes with different densities, one representative allotrope is typically selected in summary presentations, while densities for each allotrope can be stated where more detail is provided. For example, the three familiar allotropes of carbon (amorphous carbon, graphite, and diamond) have densities of 1.8–2.1, 2.267, and 3.515 g/cm3, respectively. The elements studied to date as solid samples have eight kinds of crystal structures: cubic, body-centered cubic, face-centered cubic, hexagonal, monoclinic, orthorhombic, rhombohedral, and tetragonal. For some of the synthetically produced transuranic elements, available samples have been too small to determine crystal structures. Chemical elements may also be categorized by their origin on Earth, with the first 94 considered naturally occurring, while those with atomic numbers beyond 94 have only been produced artificially as the synthetic products of man-made nuclear reactions. Of the 94 naturally occurring elements, 83 are considered primordial and either stable or weakly radioactive. The remaining 11 naturally occurring elements possess half lives too short for them to have been present at the beginning of the Solar System, and are therefore considered transient elements. Of these 11 transient elements, 5 (polonium, radon, radium, actinium, and protactinium) are relatively common decay products of thorium and uranium. The remaining 6 transient elements (technetium, promethium, astatine, francium, neptunium, and plutonium) occur only rarely, as products of rare decay modes or nuclear reaction processes involving uranium or other heavy elements. No radioactive decay has been observed for elements with atomic numbers 1 through 82, except 43 (technetium) and 61 (promethium). Observationally stable isotopes of some elements (such as tungsten and lead), however, are predicted to be slightly radioactive with very long half-lives: for example, the half-lives predicted for the observationally stable lead isotopes range from 1035 to 10189 years. Elements with atomic numbers 43, 61, and 83 through 94 are unstable enough that their radioactive decay can readily be detected. Three of these elements, bismuth (element 83), thorium (element 90), and uranium (element 92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before the formation of the Solar System. For example, at over 1.9×1019 years, over a billion times longer than the current estimated age of the universe, bismuth-209 has the longest known alpha decay half-life of any naturally occurring element. The very heaviest 24 elements (those beyond plutonium, element 94) undergo radioactive decay with short half-lives and cannot be produced as daughters of longer-lived elements, and thus are not known to occur in nature at all. The properties of the chemical elements are often summarized using the periodic table, which powerfully and elegantly organizes the elements by increasing atomic number into rows ("periods") in which the columns ("groups") share recurring ("periodic") physical and chemical properties. The current standard table contains 118 confirmed elements as of 2019. Although earlier precursors to this presentation exist, its invention is generally credited to the Russian chemist Dmitri Mendeleev in 1869, who intended the table to illustrate recurring trends in the properties of the elements. The layout of the table has been refined and extended over time as new elements have been discovered and new theoretical models have been developed to explain chemical behavior. Use of the periodic table is now ubiquitous within the academic discipline of chemistry, providing an extremely useful framework to classify, systematize and compare all the many different forms of chemical behavior. The table has also found wide application in physics, geology, biology, materials science, engineering, agriculture, medicine, nutrition, environmental health, and astronomy. Its principles are especially important in chemical engineering. The known elements have atomic numbers from 1 through 118, conventionally presented as Arabic numerals. Since the elements can be uniquely sequenced by atomic number, conventionally from lowest to highest (as in a periodic table), sets of elements are sometimes specified by such notation as "through", "beyond", or "from ... through", as in "through iron", "beyond uranium", or "from lanthanum through lutetium". The terms "light" and "heavy" are sometimes also used informally to indicate relative atomic numbers (not densities), as in "lighter than carbon" or "heavier than lead", although technically the weight or mass of atoms of an element (their atomic weights or atomic masses) do not always increase monotonically with their atomic numbers. The naming of various substances now known as elements precedes the atomic theory of matter, as names were given locally by various cultures to various minerals, metals, compounds, alloys, mixtures, and other materials, although at the time it was not known which chemicals were elements and which compounds. As they were identified as elements, the existing names for anciently-known elements (e.g., gold, mercury, iron) were kept in most countries. National differences emerged over the names of elements either for convenience, linguistic niceties, or nationalism. For a few illustrative examples: German speakers use "Wasserstoff" (water substance) for "hydrogen", "Sauerstoff" (acid substance) for "oxygen" and "Stickstoff" (smothering substance) for "nitrogen", while English and some romance languages use "sodium" for "natrium" and "potassium" for "kalium", and the French, Italians, Greeks, Portuguese and Poles prefer "azote/azot/azoto" (from roots meaning "no life") for "nitrogen". For purposes of international communication and trade, the official names of the chemical elements both ancient and more recently recognized are decided by the International Union of Pure and Applied Chemistry (IUPAC), which has decided on a sort of international English language, drawing on traditional English names even when an element's chemical symbol is based on a Latin or other traditional word, for example adopting "gold" rather than "aurum" as the name for the 79th element (Au). IUPAC prefers the British spellings "aluminium" and "caesium" over the U.S. spellings "aluminum" and "cesium", and the U.S. "sulfur" over the British "sulphur". However, elements that are practical to sell in bulk in many countries often still have locally used national names, and countries whose national language does not use the Latin alphabet are likely to use the IUPAC element names. According to IUPAC, chemical elements are not proper nouns in English; consequently, the full name of an element is not routinely capitalized in English, even if derived from a proper noun, as in californium and einsteinium. Isotope names of chemical elements are also uncapitalized if written out, e.g., carbon-12 or uranium-235. Chemical element symbols (such as Cf for californium and Es for einsteinium), are always capitalized (see below). In the second half of the twentieth century, physics laboratories became able to produce nuclei of chemical elements with half-lives too short for an appreciable amount of them to exist at any time. These are also named by IUPAC, which generally adopts the name chosen by the discoverer. This practice can lead to the controversial question of which research group actually discovered an element, a question that delayed the naming of elements with atomic number of 104 and higher for a considerable amount of time. (See element naming controversy). Precursors of such controversies involved the nationalistic namings of elements in the late 19th century. For example, lutetium was named in reference to Paris, France. The Germans were reluctant to relinquish naming rights to the French, often calling it cassiopeium. Similarly, the British discoverer of niobium originally named it columbium, in reference to the New World. It was used extensively as such by American publications before the international standardization (in 1950). Before chemistry became a science, alchemists had designed arcane symbols for both metals and common compounds. These were however used as abbreviations in diagrams or procedures; there was no concept of atoms combining to form molecules. With his advances in the atomic theory of matter, John Dalton devised his own simpler symbols, based on circles, to depict molecules. The current system of chemical notation was invented by Berzelius. In this typographical system, chemical symbols are not mere abbreviations—though each consists of letters of the Latin alphabet. They are intended as universal symbols for people of all languages and alphabets. The first of these symbols were intended to be fully universal. Since Latin was the common language of science at that time, they were abbreviations based on the Latin names of metals. Cu comes from cuprum, Fe comes from ferrum, Ag from argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin natrium. The same applies to "Fe" (ferrum) for iron, "Hg" (hydrargyrum) for mercury, "Sn" (stannum) for tin, "Au" (aurum) for gold, "Ag" (argentum) for silver, "Pb" (plumbum) for lead, "Cu" (cuprum) for copper, and "Sb" (stibium) for antimony. "W" (wolfram) for tungsten ultimately derives from German, "K" (kalium) for potassium ultimately from Arabic. Chemical symbols are understood internationally when element names might require translation. There have sometimes been differences in the past. For example, Germans in the past have used "J" (for the alternate name Jod) for iodine, but now use "I" and "Iod". The first letter of a chemical symbol is always capitalized, as in the preceding examples, and the subsequent letters, if any, are always lower case (small letters). Thus, the symbols for californium and einsteinium are Cf and Es. There are also symbols in chemical equations for groups of chemical elements, for example in comparative formulas. These are often a single capital letter, and the letters are reserved and not used for names of specific elements. For example, an "X" indicates a variable group (usually a halogen) in a class of compounds, while "R" is a radical, meaning a compound structure such as a hydrocarbon chain. The letter "Q" is reserved for "heat" in a chemical reaction. "Y" is also often used as a general chemical symbol, although it is also the symbol of yttrium. "Z" is also frequently used as a general variable group. "E" is used in organic chemistry to denote an electron-withdrawing group or an electrophile; similarly "Nu" denotes a nucleophile. "L" is used to represent a general ligand in inorganic and organometallic chemistry. "M" is also often used in place of a general metal. At least two additional, two-letter generic chemical symbols are also in informal usage, "Ln" for any lanthanide element and "An" for any actinide element. "Rg" was formerly used for any rare gas element, but the group of rare gases has now been renamed noble gases and the symbol "Rg" has now been assigned to the element roentgenium. Isotopes are distinguished by the atomic mass number (total protons and neutrons) for a particular isotope of an element, with this number combined with the pertinent element's symbol. IUPAC prefers that isotope symbols be written in superscript notation when practical, for example 12C and 235U. However, other notations, such as carbon-12 and uranium-235, or C-12 and U-235, are also used. As a special case, the three naturally occurring isotopes of the element hydrogen are often specified as H for 1H (protium), D for 2H (deuterium), and T for 3H (tritium). This convention is easier to use in chemical equations, replacing the need to write out the mass number for each atom. For example, the formula for heavy water may be written D2O instead of 2H2O. Only about 4% of the total mass of the universe is made of atoms or ions, and thus represented by chemical elements. This fraction is about 15% of the total matter, with the remainder of the matter (85%) being dark matter. The nature of dark matter is unknown, but it is not composed of atoms of chemical elements because it contains no protons, neutrons, or electrons. (The remaining non-matter part of the mass of the universe is composed of the even more mysterious dark energy). The universe's 94 naturally occurring chemical elements are thought to have been produced by at least four cosmic processes. Most of the hydrogen, helium and a very small quantity of lithium in the universe was produced primordially in the first few minutes of the Big Bang. Other three recurrently occurring later processes are thought to have produced the remaining elements. Stellar nucleosynthesis, an ongoing process inside stars, produces all elements from carbon through iron in atomic number, but little lithium, beryllium, or boron. Elements heavier in atomic number than iron, as heavy as uranium and plutonium, are produced by explosive nucleosynthesis in supernovas and other cataclysmic cosmic events. Cosmic ray spallation (fragmentation) of carbon, nitrogen, and oxygen is important to the production of lithium, beryllium and boron. During the early phases of the Big Bang, nucleosynthesis of hydrogen nuclei resulted in the production of hydrogen-1 (protium, 1H) and helium-4 (4He), as well as a smaller amount of deuterium (2H) and very minuscule amounts (on the order of 10−10) of lithium and beryllium. Even smaller amounts of boron may have been produced in the Big Bang, since it has been observed in some very old stars, while carbon has not. It is generally agreed that no heavier elements than boron were produced in the Big Bang. As a result, the primordial abundance of atoms (or ions) consisted of roughly 75% 1H, 25% 4He, and 0.01% deuterium, with only tiny traces of lithium, beryllium, and perhaps boron. Subsequent enrichment of galactic halos occurred due to stellar nucleosynthesis and supernova nucleosynthesis. However, the element abundance in intergalactic space can still closely resemble primordial conditions, unless it has been enriched by some means. On Earth (and elsewhere), trace amounts of various elements continue to be produced from other elements as products of nuclear transmutation processes. These include some produced by cosmic rays or other nuclear reactions (see cosmogenic and nucleogenic nuclides), and others produced as decay products of long-lived primordial nuclides. For example, trace (but detectable) amounts of carbon-14 (14C) are continually produced in the atmosphere by cosmic rays impacting nitrogen atoms, and argon-40 (40Ar) is continually produced by the decay of primordially occurring but unstable potassium-40 (40K). Also, three primordially occurring but radioactive actinides, thorium, uranium, and plutonium, decay through a series of recurrently produced but unstable radioactive elements such as radium and radon, which are transiently present in any sample of these metals or their ores or compounds. Three other radioactive elements, technetium, promethium, and neptunium, occur only incidentally in natural materials, produced as individual atoms by nuclear fission of the nuclei of various heavy elements or in other rare nuclear processes. The following graph (note log scale) shows the abundance of elements in our Solar System. The table shows the twelve most common elements in our galaxy (estimated spectroscopically), as measured in parts per million, by mass. Nearby galaxies that have evolved along similar lines have a corresponding enrichment of elements heavier than hydrogen and helium. The more distant galaxies are being viewed as they appeared in the past, so their abundances of elements appear closer to the primordial mixture. As physical laws and processes appear common throughout the visible universe, however, scientist expect that these galaxies evolved elements in similar abundance. The abundance of elements in the Solar System is in keeping with their origin from nucleosynthesis in the Big Bang and a number of progenitor supernova stars. Very abundant hydrogen and helium are products of the Big Bang, but the next three elements are rare since they had little time to form in the Big Bang and are not made in stars (they are, however, produced in small quantities by the breakup of heavier elements in interstellar dust, as a result of impact by cosmic rays). Beginning with carbon, elements are produced in stars by buildup from alpha particles (helium nuclei), resulting in an alternatingly larger abundance of elements with even atomic numbers (these are also more stable). In general, such elements up to iron are made in large stars in the process of becoming supernovas. Iron-56 is particularly common, since it is the most stable element that can easily be made from alpha particles (being a product of decay of radioactive nickel-56, ultimately made from 14 helium nuclei). Elements heavier than iron are made in energy-absorbing processes in large stars, and their abundance in the universe (and on Earth) generally decreases with their atomic number. The abundance of the chemical elements on Earth varies from air to crust to ocean, and in various types of life. The abundance of elements in Earth's crust differs from that in the Solar System (as seen in the Sun and heavy planets like Jupiter) mainly in selective loss of the very lightest elements (hydrogen and helium) and also volatile neon, carbon (as hydrocarbons), nitrogen and sulfur, as a result of solar heating in the early formation of the solar system. Oxygen, the most abundant Earth element by mass, is retained on Earth by combination with silicon. Aluminum at 8% by mass is more common in the Earth's crust than in the universe and solar system, but the composition of the far more bulky mantle, which has magnesium and iron in place of aluminum (which occurs there only at 2% of mass) more closely mirrors the elemental composition of the solar system, save for the noted loss of volatile elements to space, and loss of iron which has migrated to the Earth's core. The composition of the human body, by contrast, more closely follows the composition of seawater—save that the human body has additional stores of carbon and nitrogen necessary to form the proteins and nucleic acids, together with phosphorus in the nucleic acids and energy transfer molecule adenosine triphosphate (ATP) that occurs in the cells of all living organisms. Certain kinds of organisms require particular additional elements, for example the magnesium in chlorophyll in green plants, the calcium in mollusc shells, or the iron in the hemoglobin in vertebrate animals' red blood cells. |Elements in our galaxy||Parts per million| The concept of an "element" as an undivisible substance has developed through three major historical phases: Classical definitions (such as those of the ancient Greeks), chemical definitions, and atomic definitions. Ancient philosophy posited a set of classical elements to explain observed patterns in nature. These elements originally referred to earth, water, air and fire rather than the chemical elements of modern science. The term 'elements' (stoicheia) was first used by the Greek philosopher Plato in about 360 BCE in his dialogue Timaeus, which includes a discussion of the composition of inorganic and organic bodies and is a speculative treatise on chemistry. Plato believed the elements introduced a century earlier by Empedocles were composed of small polyhedral forms: tetrahedron (fire), octahedron (air), icosahedron (water), and cube (earth). Element – one of those bodies into which other bodies can decompose, and that itself is not capable of being divided into other. In 1661, Robert Boyle proposed his theory of corpuscularism which favoured the analysis of matter as constituted by irreducible units of matter (atoms) and, choosing to side with neither Aristotle's view of the four elements nor Paracelsus' view of three fundamental elements, left open the question of the number of elements. The first modern list of chemical elements was given in Antoine Lavoisier's 1789 Elements of Chemistry, which contained thirty-three elements, including light and caloric. By 1818, Jöns Jakob Berzelius had determined atomic weights for forty-five of the forty-nine then-accepted elements. Dmitri Mendeleev had sixty-six elements in his periodic table of 1869. From Boyle until the early 20th century, an element was defined as a pure substance that could not be decomposed into any simpler substance. Put another way, a chemical element cannot be transformed into other chemical elements by chemical processes. Elements during this time were generally distinguished by their atomic weights, a property measurable with fair accuracy by available analytical techniques. The 1913 discovery by English physicist Henry Moseley that the nuclear charge is the physical basis for an atom's atomic number, further refined when the nature of protons and neutrons became appreciated, eventually led to the current definition of an element based on atomic number (number of protons per atomic nucleus). The use of atomic numbers, rather than atomic weights, to distinguish elements has greater predictive value (since these numbers are integers), and also resolves some ambiguities in the chemistry-based view due to varying properties of isotopes and allotropes within the same element. Currently, IUPAC defines an element to exist if it has isotopes with a lifetime longer than the 10−14 seconds it takes the nucleus to form an electronic cloud. By 1914, seventy-two elements were known, all naturally occurring. The remaining naturally occurring elements were discovered or isolated in subsequent decades, and various additional elements have also been produced synthetically, with much of that work pioneered by Glenn T. Seaborg. In 1955, element 101 was discovered and named mendelevium in honor of D.I. Mendeleev, the first to arrange the elements in a periodic manner. Most recently, the synthesis of element 118 (since named oganesson) was reported in October 2006, and the synthesis of element 117 (tennessine) was reported in April 2010. Ten materials familiar to various prehistoric cultures are now known to be chemical elements: Carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin, and zinc. Three additional materials now accepted as elements, arsenic, antimony, and bismuth, were recognized as distinct substances prior to 1500 AD. Phosphorus, cobalt, and platinum were isolated before 1750. Most of the remaining naturally occurring chemical elements were identified and characterized by 1900, including: Elements isolated or produced since 1900 include: The first transuranium element (element with atomic number greater than 92) discovered was neptunium in 1940. Since 1999 claims for the discovery of new elements have been considered by the IUPAC/IUPAP Joint Working Party. As of January 2016, all 118 elements have been confirmed as discovered by IUPAC. The discovery of element 112 was acknowledged in 2009, and the name copernicium and the atomic symbol Cn were suggested for it. The name and symbol were officially endorsed by IUPAC on 19 February 2010. The heaviest element that is believed to have been synthesized to date is element 118, oganesson, on 9 October 2006, by the Flerov Laboratory of Nuclear Reactions in Dubna, Russia. Tennessine, element 117 was the latest element claimed to be discovered, in 2009. On 28 November 2016, scientists at the IUPAC officially recognized the names for four of the newest chemical elements, with atomic numbers 113, 115, 117, and 118. The following sortable table shows the 118 known chemical elements. |List of chemical elements| |Atomic number||Symbol||Element||Etymology||Group||Period||Atomic weight||Density||Melting point||Boiling point||Specific heat capacity||Electronegativity||Abundance in Earth's crust[I]| |1||H||Hydrogen||Greek elements hydro- and -gen, 'water-forming'||1||1||1.008[II][III][IV][V]||0.00008988||14.01||20.28||14.304||2.20||1400| |2||He||Helium||Greek hḗlios, 'sun'||18||1||4.002602(2)[II][IV]||0.0001785||—[VI]||4.22||5.193||–||0.008| |3||Li||Lithium||Greek líthos, 'stone'||1||2||6.94[II][III][IV][VII][V]||0.534||453.69||1560||3.582||0.98||20| |4||Be||Beryllium||Beryl, a mineral (ultimately from the name of Belur in southern India)||2||2||9.0121831(5)||1.85||1560||2742||1.825||1.57||2.8| |5||B||Boron||Borax, a mineral (from Arabic bawraq)||13||2||10.81[II][III][IV][V]||2.34||2349||4200||1.026||2.04||10| |6||C||Carbon||Latin carbo, 'coal'||14||2||12.011[II][IV][V]||2.267||3800||4300||0.709||2.55||200| |7||N||Nitrogen||Greek nítron and -gen, 'niter-forming'||15||2||14.007[II][IV][V]||0.0012506||63.15||77.36||1.04||3.04||19| |8||O||Oxygen||Greek oxy- and -gen, 'acid-forming'||16||2||15.999[II][IV][V]||0.001429||54.36||90.20||0.918||3.44||461000| |9||F||Fluorine||Latin fluere, 'to flow'||17||2||18.998403163(6)||0.001696||53.53||85.03||0.824||3.98||585| |10||Ne||Neon||Greek néon, 'new'||18||2||20.1797(6)[II][III]||0.0008999||24.56||27.07||1.03||–||0.005| |11||Na||Sodium||English soda (the symbol Na is derived from New Latin natrium, coined from German Natron, 'natron')||1||3||22.98976928(2)||0.971||370.87||1156||1.228||0.93||23600| |12||Mg||Magnesium||Magnesia, a district of Eastern Thessaly in Greece||2||3||24.305[V]||1.738||923||1363||1.023||1.31||23300| |13||Al||Aluminium||alumina, from Latin alumen (gen. aluminis), 'bitter salt, alum'||13||3||26.9815384(3)||2.698||933.47||2792||0.897||1.61||82300| |14||Si||Silicon||Latin silex, 'flint' (originally silicium)||14||3||28.085[IV][V]||2.3296||1687||3538||0.705||1.9||282000| |15||P||Phosphorus||Greek phōsphóros, 'light-bearing'||15||3||30.973761998(5)||1.82||317.30||550||0.769||2.19||1050| |16||S||Sulfur||Latin sulphur, 'brimstone'||16||3||32.06[II][IV][V]||2.067||388.36||717.87||0.71||2.58||350| |17||Cl||Chlorine||Greek chlōrós, 'greenish yellow'||17||3||35.45[II][III][IV][V]||0.003214||171.6||239.11||0.479||3.16||145| |18||Ar||Argon||Greek argós, 'idle' (because of its inertness)||18||3||39.95[II][IV][V]||0.0017837||83.80||87.30||0.52||–||3.5| |19||K||Potassium||New Latin potassa, 'potash' (the symbol K is derived from Latin kalium)||1||4||39.0983(1)||0.862||336.53||1032||0.757||0.82||20900| |20||Ca||Calcium||Latin calx, 'lime'||2||4||40.078(4)[II]||1.54||1115||1757||0.647||1||41500| |21||Sc||Scandium||Latin Scandia, 'Scandinavia'||3||4||44.955908(5)||2.989||1814||3109||0.568||1.36||22| |22||Ti||Titanium||Titans, the sons of the Earth goddess of Greek mythology||4||4||47.867(1)||4.54||1941||3560||0.523||1.54||5650| |23||V||Vanadium||Vanadis, an Old Norse name for the Scandinavian goddess Freyja||5||4||50.9415(1)||6.11||2183||3680||0.489||1.63||120| |24||Cr||Chromium||Greek chróma, 'colour'||6||4||51.9961(6)||7.15||2180||2944||0.449||1.66||102| |25||Mn||Manganese||Corrupted from magnesia negra; see Magnesium||7||4||54.938043(2)||7.44||1519||2334||0.479||1.55||950| |26||Fe||Iron||English word (the symbol Fe is derived from Latin ferrum)||8||4||55.845(2)||7.874||1811||3134||0.449||1.83||56300| |27||Co||Cobalt||German Kobold, 'goblin'||9||4||58.933194(3)||8.86||1768||3200||0.421||1.88||25| |28||Ni||Nickel||Nickel, a mischievous sprite of German miner mythology||10||4||58.6934(4)||8.912||1728||3186||0.444||1.91||84| |29||Cu||Copper||English word, from Latin cuprum, from Ancient Greek Kýpros 'Cyprus'||11||4||63.546(3)[IV]||8.96||1357.77||2835||0.385||1.9||60| |30||Zn||Zinc||Most likely from German Zinke, 'prong' or 'tooth', though some suggest Persian sang, 'stone'||12||4||65.38(2)||7.134||692.88||1180||0.388||1.65||70| |31||Ga||Gallium||Latin Gallia, 'France'||13||4||69.723(1)||5.907||302.9146||2673||0.371||1.81||19| |32||Ge||Germanium||Latin Germania, 'Germany'||14||4||72.630(8)||5.323||1211.40||3106||0.32||2.01||1.5| |33||As||Arsenic||French arsenic, from Greek arsenikón 'yellow arsenic' (influenced by arsenikós, 'masculine' or 'virile'), from a West Asian wanderword ultimately from Old Iranian *zarniya-ka, 'golden'||15||4||74.921595(6)||5.776||1090[VIII]||887||0.329||2.18||1.8| |34||Se||Selenium||Greek selḗnē, 'moon'||16||4||78.971(8)[IV]||4.809||453||958||0.321||2.55||0.05| |35||Br||Bromine||Greek brômos, 'stench'||17||4||79.904[V]||3.122||265.8||332.0||0.474||2.96||2.4| |36||Kr||Krypton||Greek kryptós, 'hidden'||18||4||83.798(2)[II][III]||0.003733||115.79||119.93||0.248||3||1×10−4| |37||Rb||Rubidium||Latin rubidus, 'deep red'||1||5||85.4678(3)[II]||1.532||312.46||961||0.363||0.82||90| |38||Sr||Strontium||Strontian, a village in Scotland||2||5||87.62(1)[II][IV]||2.64||1050||1655||0.301||0.95||370| |39||Y||Yttrium||Ytterby, Sweden, where it was found||3||5||88.90584(1)||4.469||1799||3609||0.298||1.22||33| |40||Zr||Zirconium||Zircon, a mineral||4||5||91.224(2)[II]||6.506||2128||4682||0.278||1.33||165| |41||Nb||Niobium||Niobe, daughter of king Tantalus from Greek mythology||5||5||92.90637(1)||8.57||2750||5017||0.265||1.6||20| |42||Mo||Molybdenum||Greek molýbdaina, 'piece of lead', from mólybdos, 'lead', due to confusion with lead ore galena (PbS)||6||5||95.95(1)[II]||10.22||2896||4912||0.251||2.16||1.2| |43||Tc||Technetium||Greek tekhnētós, 'artificial'||7||5||[IX]||11.5||2430||4538||–||1.9||~ 3×10−9[X]| |44||Ru||Ruthenium||New Latin Ruthenia, 'Russia'||8||5||101.07(2)[II]||12.37||2607||4423||0.238||2.2||0.001| |45||Rh||Rhodium||Greek rhodóeis, 'rose-coloured', from rhódon, 'rose'||9||5||102.90549(2)||12.41||2237||3968||0.243||2.28||0.001| |46||Pd||Palladium||Asteroid Pallas, considered a planet at the time||10||5||106.42(1)[II]||12.02||1828.05||3236||0.244||2.2||0.015| |47||Ag||Silver||English word (The symbol is derived from Latin argentum)||11||5||107.8682(2)[II]||10.501||1234.93||2435||0.235||1.93||0.075| |48||Cd||Cadmium||New Latin cadmia, from King Kadmos||12||5||112.414(4)[II]||8.69||594.22||1040||0.232||1.69||0.159| |49||In||Indium||Latin indicum, 'indigo' (colour found in its spectrum)||13||5||114.818(1)||7.31||429.75||2345||0.233||1.78||0.25| |50||Sn||Tin||English word (The symbol is derived from Latin stannum)||14||5||118.710(7)[II]||7.287||505.08||2875||0.228||1.96||2.3| |51||Sb||Antimony||Latin antimonium, the origin of which is uncertain: folk etymologies suggest it is derived from Greek antí ('against') + mónos ('alone'), or Old French anti-moine, 'Monk's bane', but it could plausibly be from or related to Arabic ʾiṯmid, 'antimony', reformatted as a Latin word. (The symbol is derived from Latin stibium 'stibnite'.)||15||5||121.760(1)[II]||6.685||903.78||1860||0.207||2.05||0.2| |52||Te||Tellurium||Latin tellus, 'the ground, earth'||16||5||127.60(3)[II]||6.232||722.66||1261||0.202||2.1||0.001| |53||I||Iodine||French iode, from Greek ioeidḗs, 'violet'||17||5||126.90447(3)||4.93||386.85||457.4||0.214||2.66||0.45| |54||Xe||Xenon||Greek xénon, neuter form of xénos 'strange'||18||5||131.293(6)[II][III]||0.005887||161.4||165.03||0.158||2.6||3×10−5| |55||Cs||Caesium||Latin caesius, 'sky-blue'||1||6||132.90545196(6)||1.873||301.59||944||0.242||0.79||3| |56||Ba||Barium||Greek barýs, 'heavy'||2||6||137.327(7)||3.594||1000||2170||0.204||0.89||425| |57||La||Lanthanum||Greek lanthánein, 'to lie hidden'||3||6||138.90547(7)[II]||6.145||1193||3737||0.195||1.1||39| |58||Ce||Cerium||Dwarf planet Ceres, considered a planet at the time||6||140.116(1)[II]||6.77||1068||3716||0.192||1.12||66.5| |59||Pr||Praseodymium||Greek prásios dídymos, 'green twin'||6||140.90766(1)||6.773||1208||3793||0.193||1.13||9.2| |60||Nd||Neodymium||Greek néos dídymos, 'new twin'||6||144.242(3)[II]||7.007||1297||3347||0.19||1.14||41.5| |61||Pm||Promethium||Prometheus of Greek mythology||6||[IX]||7.26||1315||3273||–||1.13||2×10−19[X]| |62||Sm||Samarium||Samarskite, a mineral named after Colonel Vasili Samarsky-Bykhovets, Russian mine official||6||150.36(2)[II]||7.52||1345||2067||0.197||1.17||7.05| |64||Gd||Gadolinium||Gadolinite, a mineral named after Johan Gadolin, Finnish chemist, physicist and mineralogist||6||157.25(3)[II]||7.895||1585||3546||0.236||1.2||6.2| |65||Tb||Terbium||Ytterby, Sweden, where it was found||6||158.925354(8)||8.229||1629||3503||0.182||1.2||1.2| |66||Dy||Dysprosium||Greek dysprósitos, 'hard to get'||6||162.500(1)[II]||8.55||1680||2840||0.17||1.22||5.2| |67||Ho||Holmium||New Latin Holmia, 'Stockholm'||6||164.930328(7)||8.795||1734||2993||0.165||1.23||1.3| |68||Er||Erbium||Ytterby, Sweden, where it was found||6||167.259(3)[II]||9.066||1802||3141||0.168||1.24||3.5| |69||Tm||Thulium||Thule, the ancient name for an unclear northern location||6||168.934218(6)||9.321||1818||2223||0.16||1.25||0.52| |70||Yb||Ytterbium||Ytterby, Sweden, where it was found||6||173.045(10)[II]||6.965||1097||1469||0.155||1.1||3.2| |71||Lu||Lutetium||Latin Lutetia, 'Paris'||6||174.9668(1)[II]||9.84||1925||3675||0.154||1.27||0.8| |72||Hf||Hafnium||New Latin Hafnia, 'Copenhagen' (from Danish havn)||4||6||178.49(2)||13.31||2506||4876||0.144||1.3||3| |73||Ta||Tantalum||King Tantalus, father of Niobe from Greek mythology||5||6||180.94788(2)||16.654||3290||5731||0.14||1.5||2| |74||W||Tungsten||Swedish tung sten, 'heavy stone' (The symbol W is from Wolfram, a name used for the element in many languages, originally from Middle High German wolf-rahm (wolf's foam) describing the mineral wolframite)||6||6||183.84(1)||19.25||3695||5828||0.132||2.36||1.3| |75||Re||Rhenium||Latin Rhenus, 'the Rhine'||7||6||186.207(1)||21.02||3459||5869||0.137||1.9||7×10−4| |76||Os||Osmium||Greek osmḗ, 'smell'||8||6||190.23(3)[II]||22.61||3306||5285||0.13||2.2||0.002| |77||Ir||Iridium||Iris, the Greek goddess of the rainbow||9||6||192.217(2)||22.56||2719||4701||0.131||2.2||0.001| |78||Pt||Platinum||Spanish platina, 'little silver', from plata 'silver'||10||6||195.084(9)||21.46||2041.4||4098||0.133||2.28||0.005| |79||Au||Gold||English word (the symbol Au is derived from Latin aurum)||11||6||196.966570(4)||19.282||1337.33||3129||0.129||2.54||0.004| |80||Hg||Mercury||Mercury, Roman god of commerce, communication, and luck, known for his speed and mobility (the symbol Hg derives from the element's Latin name hydrargyrum, from Greek hydrárgyros, 'water-silver')||12||6||200.592(3)||13.5336||234.43||629.88||0.14||2||0.085| |81||Tl||Thallium||Greek thallós, 'green shoot or twig'||13||6||204.38[V]||11.85||577||1746||0.129||1.62||0.85| |82||Pb||Lead||English word (the symbol Pb is derived from Latin plumbum)||14||6||207.2(1)[II][IV]||11.342||600.61||2022||0.129||1.87||14| |83||Bi||Bismuth||German Wismut, from weiß Masse 'white mass', unless from Arabic||15||6||208.98040(1)[IX]||9.807||544.7||1837||0.122||2.02||0.009| |84||Po||Polonium||Latin Polonia, 'Poland' (the home country of Marie Curie)||16||6||[IX]||9.32||527||1235||–||2.0||2×10−10[X]| |85||At||Astatine||Greek ástatos, 'unstable'||17||6||[IX]||7||575||610||–||2.2||3×10−20[X]| |86||Rn||Radon||Radium emanation, originally the name of the isotope Radon-222.||18||6||[IX]||0.00973||202||211.3||0.094||2.2||4×10−13[X]| |88||Ra||Radium||French radium, from Latin radius, 'ray'||2||7||[IX]||5.5||973||2010||0.094||0.9||9×10−7[X]| |89||Ac||Actinium||Greek aktís, 'ray'||3||7||[IX]||10.07||1323||3471||0.12||1.1||5.5×10−10[X]| |90||Th||Thorium||Thor, the Scandinavian god of thunder||7||232.0377(4)[IX][II]||11.72||2115||5061||0.113||1.3||9.6| |91||Pa||Protactinium||Proto- (from Greek prôtos, 'first, before') + actinium, since actinium is produced through the radioactive decay of protactinium||7||231.03588(1)[IX]||15.37||1841||4300||–||1.5||1.4×10−6[X]| |92||U||Uranium||Uranus, the seventh planet in the Solar System||7||238.02891(3)[IX]||18.95||1405.3||4404||0.116||1.38||2.7| |93||Np||Neptunium||Neptune, the eighth planet in the Solar System||7||[IX]||20.45||917||4273||–||1.36||≤ 3×10−12[X]| |94||Pu||Plutonium||Dwarf planet Pluto, considered the ninth planet in the Solar System at the time||7||[IX]||19.84||912.5||3501||–||1.28||≤ 3×10−11[X]| |95||Am||Americium||The Americas, as the element was first synthesised on the continent, by analogy with europium||7||[IX]||13.69||1449||2880||–||1.13||0[XI]| |96||Cm||Curium||Pierre Curie and Marie Curie, French physicists and chemists||7||[IX]||13.51||1613||3383||–||1.28||0[XI]| |97||Bk||Berkelium||Berkeley, California, where the element was first synthesised, by analogy with terbium||7||[IX]||14.79||1259||2900||–||1.3||0[XI]| |98||Cf||Californium||California, where the element was first synthesised||7||[IX]||15.1||1173||(1743)[XII]||–||1.3||0[XI]| |99||Es||Einsteinium||Albert Einstein, German physicist||7||[IX]||8.84||1133||(1269)[XII]||–||1.3||0[XI]| |100||Fm||Fermium||Enrico Fermi, Italian physicist||7||[IX]||(9.7)[XII]||(1125)[XII]||–||–||1.3||0[XI]| |101||Md||Mendelevium||Dmitri Mendeleev, Russian chemist and inventor who proposed the periodic table||7||[IX]||(10.3)[XII]||(1100)[XII]||–||–||1.3||0[XI]| |102||No||Nobelium||Alfred Nobel, Swedish chemist and engineer||7||[IX]||(9.9)[XII]||(1100)[XII]||–||–||1.3||0[XI]| |103||Lr||Lawrencium||Ernest Lawrence, American physicist||7||[IX]||(15.6)[XII]||(1900)[XII]||–||–||1.3||0[XI]| |104||Rf||Rutherfordium||Ernest Rutherford, chemist and physicist from New Zealand||4||7||[IX]||(23.2)[XII]||(2400)[XII]||(5800)[XII]||–||–||0[XI]| |105||Db||Dubnium||Dubna, Russia, where the Joint Institute for Nuclear Research is located||5||7||[IX]||(29.3)[XII]||–||–||–||–||0[XI]| |106||Sg||Seaborgium||Glenn T. Seaborg, American chemist||6||7||[IX]||(35.0)[XII]||–||–||–||–||0[XI]| |107||Bh||Bohrium||Niels Bohr, Danish physicist||7||7||[IX]||(37.1)[XII]||–||–||–||–||0[XI]| |108||Hs||Hassium||New Latin Hassia, 'Hesse' (a state in Germany)||8||7||[IX]||(40.7)[XII]||–||–||–||–||0[XI]| |109||Mt||Meitnerium||Lise Meitner, Austrian physicist||9||7||[IX]||(37.4)[XII]||–||–||–||–||0[XI]| |110||Ds||Darmstadtium||Darmstadt, Germany, where the element was first synthesised||10||7||[IX]||(34.8)[XII]||–||–||–||–||0[XI]| |111||Rg||Roentgenium||Wilhelm Conrad Röntgen, German physicist||11||7||[IX]||(28.7)[XII]||–||–||–||–||0[XI]| |112||Cn||Copernicium||Nicolaus Copernicus, Polish astronomer||12||7||[IX]||(14.0)[XII]||(283)[XIII]||(340)[XIII]||–||–||0[XI]| |113||Nh||Nihonium||Japanese Nihon, 'Japan' (where the element was first synthesised)||13||7||[IX]||(16)[XII]||(700)[XII]||(1400)[XII]||–||–||0[XI]| |114||Fl||Flerovium||Flerov Laboratory of Nuclear Reactions, part of JINR, where the element was synthesised; itself named after Georgy Flyorov, Russian physicist||14||7||[IX]||(14)[XII]||–||~210||–||–||0[XI]| |115||Mc||Moscovium||Moscow Oblast, Russia, where the element was first synthesised||15||7||[IX]||(13.5)[XII]||(700)[XII]||(1400)[XII]||–||–||0[XI]| |116||Lv||Livermorium||Lawrence Livermore National Laboratory in Livermore, California, which collaborated with JINR on its synthesis||16||7||[IX]||(12.9)[XII]||(700)[XII]||(1100)[XII]||–||–||0[XI]| |117||Ts||Tennessine||Tennessee, United States (where Oak Ridge National Laboratory is located)||17||7||[IX]||(7.2)[XII]||(700)[XII]||(883)[XII]||–||–||0[XI]| |118||Og||Oganesson||Yuri Oganessian, Russian physicist||18||7||[IX]||(5.0)[XII][XIV]||(320)[XII]||(~350)[XII][XV]||–||–||0[XI]| |Wikimedia Commons has media related to Chemical elements.|

We present our effort to detect and characterize transiting systems with small exoplanets. First we present our on-going project to detect transiting exoplanets around late-type stars. As many authors point out, late-type stars can host potentially habitable rocky planets, whose transits are detectable with 2-meter class telescopes. We aim at detecting (small-sized) transiting exoplanets around M-type stars and are conducting a survey using the Okayama 1.88m telescope. We introduce our campaign at Okayama. Next we discuss the characterization of small-sized exoplanets. We focus on the measurement of the spin-orbit angle, the angle between the stellar spin axis and planetary orbital axis. The spin-orbit relations are of great importance in discussing planetary formations, evolutions, and migrations. To this point, the Rossiter-McLaughlin (RM) effect, an apparent radial velocity anomaly during a planetary transit, has been mainly investigated to measure the projected spin-orbit angles. However, as the size of the transiting planet becomes smaller, the detection of the RM effect becomes challenging because of the small RM signal. We have newly developed a technique to investigate spin-orbit relations for smaller planets by combining Kepler's ultra-precise photometry and spectroscopic measurements. We show that, contrary to planetary systems with close-in giant planets, most of the systems with small-sized planets (including Earth-sized ones) have smaller spin-orbit angles, which implies a different evolutional history of the planetary systems. We also discuss future prospects on the detection and characterization of smaller transiting exoplanets.

So if the Sun came from the dwarf, we’d be orbiting the Milky Way at that angle ourselves! Studies of the Sun’s motion relative to the plane of the Milky Way (using the stars, globular clusters, other galaxies, and many other sources) make it a rock-solid certainty that the Sun’s orbit is in fact of the Milky Way. First, the plane of the solar system (defined, really, by the plane of the Earth’s orbit) is tilted with respect to the Milky Way’s plane by about 60 degrees or so. If we belong to the dwarf galaxy, what are the odds that at this point in time we’d be almost exactly in the center of the plane of the Milky Way? In other words, at one point in Earth’s orbit, you can draw a line from the Earth through the Sun and it will pass very near the center of the Milky Way (if you were at the Galactic center, you’d see our solar system "edge-on"). If our solar system were aligned with the dwarf stream, that wouldn’t happen (from the Milky Way’s center, the solar system would appear to be "face-on"). “Remarkably, stars from Sagittarius are now raining down onto our present position in the Milky Way. We have to re-think our assumptions about the Milky Way galaxy to account for this contamination.” Wow, that sounds like Majewski, the lead author of the scientific paper, agrees that the Sun must come from the dwarf galaxy, doesn’t it? The vast majority are, to be sure (or else we would have discovered the interloping galaxy a long time ago), and astronomers will have to be careful when looking at individual stars. To be fair, this is from the original press release. But the way it’s placed in the Viewzone article is misleading. I’m not a fan of attacking the messenger, but sometimes it pays to look at someone’s pedigree when they are making a huge claim like this.

The cool thing about spacecraft is that they continue on for as long as possible after their primary mission is completed. For instance, Voyager 2 crossed into interstellar space last year and the Mars rover Opportunity has been functional for 14 years. New Horizons provided some of the best images of Pluto we’ve ever seen in 2015, but it’s mission didn’t stop there. The plucky spacecraft kept journeying into the Kuiper Belt and gave scientists an unprecedented view of a new mysterious object. 2014 MU69 is a celestial body in the Kuiper Belt that showed up as a very tiny pixel for most of our observational history. New Horizons close flyby will give scientists the closest-ever view of an object from the Kuiper Belt. So that’s a lot to unpack. Let’s see if we can do this incredible continuing mission justice. What’s the Kuiper Belt? The Kuiper Belt is a region of space, a doughnut-shaped ring of icy objects around the Sun, extending just beyond the orbit of Neptune from about 30 to 55 AU. The known icy worlds and comets in both regions are much smaller than Earth’s Moon. Comets that take less than 200 years to orbit the Sun probably originate in the Belt. Things get really weird that far out, too. Some of these tiny little planetoids have their own even tinier moons. One of them, Haumea, is shaped like an egg and has a ring like Saturn. It’s also really, really big. There could be up to hundreds of thousands of those little planetoids in its expanse. Oh, and also trillions of comets. Our solar system is a lot more interesting on its edges than we learned about in middle school, huh? NASA has a great quick explainer with a few more facts on the Kuiper Belt here. What is 2014 MU69? I’ll let New Horizons scientists Alan Stern explain a bit with a tweet. TALLY HO ULTIMA THULE!! An ancient relic of solar system formation, 4+ billion miles away, as dark as dirt, & shining only in the faint sunlight of the Kuiper Belt. Here it is, in a New Horizons imaging sequence. SEE IT MOVE, AGAINST THE STARS? TALLY HO! We’ll be there on Monday! pic.twitter.com/EExUpK6wLt — Alan Stern (@AlanStern) December 26, 2018 Early in the morning on Jan. 1, New Horizons flew past this cool object, giving NASA and the world its first up-close look at the weird and wild things in the Kuiper Belt. Nicknamed Ultima Thule, 2014 MU69 is 4 billion miles away from the Sun, is shaped like a bowling pin, spins like a propeller and is only about 20 by 10 miles in size. One of the mysteries that New Horizons already solved was Ultima Thule’s brightness. See, earlier images of the object didn’t show any variation in its brightness. This could have been caused by many things, but spinning like a propeller means the same side is always facing the Sun, thus showing less variation in brightness. What did New Horizons do? New Horizons got within 2,200 miles of the object, collecting data and taking high resolution photos. That data is already being beamed back to NASA, a process that will go on for 20 months. “New Horizons performed as planned today, conducting the farthest exploration of any world in history — 4 billion miles from the Sun,” said Principal Investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado. “The data we have look fantastic and we’re already learning about Ultima from up close. From here out the data will just get better and better!” Almost 13 years after the launch, the spacecraft will continue its exploration of the Kuiper Belt until at least 2021. Team members plan to propose more Kuiper Belt exploration. “Congratulations to NASA’s New Horizons team, Johns Hopkins Applied Physics Laboratory and the Southwest Research Institute for making history yet again. In addition to being the first to explore Pluto, today New Horizons flew by the most distant object ever visited by a spacecraft and became the first to directly explore an object that holds remnants from the birth of our solar system,” said NASA Administrator Jim Bridenstine. “This is what leadership in space exploration is all about.”

To quote another great space adventurer: “Almost there!” The New Horizons probe, launched in 2006, will finally reach Pluto next Tuesday, providing the first close-up view of the tiny, icy world since we discovered it in 1930. We’re already seeing features never glimpsed before. It’s a truly historic occasion, right up there with the Dawn mission to the giant asteroid Ceres, known since 1801 but never seen clearly before this year. But what is Pluto? Here are the facts: Pluto is a small world of rock and ice, a little less dense than Earth or the Moon. It’s about two-thirds the diameter of the Moon, and about 18 percent of the Moon’s mass, or 0.2 percent of Earth’s mass. Pluto has four really tiny moons—Nix, Hydra, Kerberos, and Styx—and it is locked in mutual orbit with Charon, a much larger moon roughly 10 percent of Pluto’s mass. I suspect everyone is impatient with me now, because I’ve carefully avoided calling Pluto a planet, a dwarf planet, or anything else. According to the International Astronomical Union (IAU), a body of professional astronomers that meets every three years, Pluto is not a planet. But I don’t care if it’s called a “planet” or not. The real point is that Pluto is really awesome, whatever we call it: it’s a different sort of world than any we’ve yet visited. It resembles some of the outer Solar System moons of Neptune and Saturn, but has big differences too. Pluto’s uniqueness is independent of what we decide to call a “planet.” (I do admit the “Pluto is obviously a planet!” crowd sometimes makes me want to say it ain’t just out of spite.) The controversial decision to change Pluto’s status was made by the IAU in 2006, based on a definition of “planet” that frankly sucks. The definition (simplified!) says a planet must: 1. Orbit the Sun directly2. Be big enough to be shaped by the balance of gravity and internal forces to be spherical (or roughly so)3. Be the gravitationally dominant object in its orbit, clearing out other smaller bodies The first and third points are the ones that bug a lot of scientists in the pro-Planet Pluto camp. Exoplanets orbit other stars, so by this definition they aren’t “planets,” and “clearing its orbit” is a criterion that supposedly indisputable planets like Earth or Neptune sometimes pass and sometimes fail. The problem ultimately with the IAU’s definition (in this grouch’s opinion) is that it’s designed to exclude. The first criterion is intended to exclude the planet-like moons: Titan, Ganymede, the Moon, Charon, and so forth. The third is intended specifically to exclude Pluto and other largish icy worlds at the edge of the Solar System, which have orbits regularly crossing other orbits. But both of these end up feeling more artificial than intuitive: If you have to do a sophisticated calculation to determine if something is actually a planet, then it’s not much value for classification. But it’s also equally clear that the old “nine planets” view of the Solar System is dead. Eris (discovered in 2005) is almost exactly the same size as Pluto, but slightly more massive. Makemake, Quaoar, Haumea, Orcus, and several more objects are smaller but fall into the same general category as Pluto: worlds of ice and rock orbiting beyond Neptune. Any definition of “planet” including Pluto but excluding these other worlds would be at least as crappy as the IAU’s crap definition. It made sense to include Pluto back in 1930—astronomers initially thought it might be nearly as big as Earth, because we didn’t have a good gauge of how bright it was. Over the decades, various measurements refined both its size and mass downward, to the point where a joke paper in 1980 predicted Pluto would vanish completely by 1984, then reappear. (Yeah, scientists have odd senses of humor.) Measuring a small world’s size from a distance is challenging, though: We have to wait for it to pass in front of a star and time how long it takes for the star’s light to reappear. The discovery of the big moon Charon in 1978 gave scientists the first good estimate of Pluto’s mass, but we’re still refining size measurements. Over time, it became clear Pluto is different than the eight planets. It is neither gaseous like Jupiter nor quite as rocky as Earth, and it is much smaller than Mercury. It orbits on a different plane than the big planets, and has an elongated orbit (though not as stretched out as a comet’s). The discovery of Eris, Quaoar, and the like was actually good in that sense: Pluto ceased being an oddball and became the first of a new group of objects. Whether you want to call them planets or not, Pluto and its kin are an important population out beyond Neptune. Pluto is the first among equals; each of these worlds has unique things that make them interesting. If one is a planet, they all are planets. And whether Pluto is a planet or not, it’s very interesting. Astronomers are already examining the New Horizons images to figure out why Pluto’s surface is so dark near the equator, and what the various splotches could be. Pluto has a thin atmosphere of nitrogen, methane, and other gases that might sometimes freeze entirely onto the surface, so that might be part of the answer. Next Tuesday, we’ll get the data to help us know for sure. Like many of us, I’ll be watching NASA TV around 9 p.m. U.S. Eastern time to see the first reports from Pluto. (If you’re near Cleveland, you can even watch with me and other local scientists! I’m the guy in the bowler hat.) Every new world we study teaches us something new about the Solar System, and Pluto will be no different—whatever name we give it.

Sunshine duration or sunshine hours is a climatological indicator, measuring duration of sunshine in given period (usually, a day or a year) for a given location on Earth, typically expressed as an averaged value over several years. It is a general indicator of cloudiness of a location, and thus differs from insolation, which measures the total energy delivered by sunlight over a given period. Sunshine duration is usually expressed in hours per year, or in (average) hours per day. The first measure indicates the general sunniness of a location compared with other places, while the latter allows for comparison of sunshine in various seasons in the same location. Another often-used measure is percentage ratio of recorded bright sunshine duration and daylight duration in the observed period. An important use of sunshine duration data is to characterize the climate of sites, especially of health resorts. This also takes into account the psychological effect of strong solar light on human well-being. It is often used to promote tourist destinations. If the Sun were to be above the horizon 50% of the time for a standard year consisting of 8,760 hours, apparent maximal daytime duration would be 4,380 hours for any point on Earth. However, there are physical and astronomical effects that change that picture. Namely, atmospheric refraction allows the Sun to be still visible even when it physically sets below the horizon. For that reason, average daytime (disregarding cloud effects) is longest in polar areas, where the apparent Sun spends the most time around the horizon. Places on the Arctic Circle have the longest total annual daytime, 4,647 hours, while the North Pole receives 4,575. Because of elliptic nature of the Earth's orbit, the Southern Hemisphere is not symmetrical: the Antarctic Circle, with 4,530 hours of daylight, receives five days less of sunshine than its antipodes. The Equator has a total daytime of 4,422 hours per year. Definition and measurement Given the theoretical maximum of daytime duration for a given location, there is also a practical consideration at which point the amount of daylight is sufficient to be treated as a "sunshine hour". "Bright" sunshine hours represent the total hours when the sunlight is stronger than a specified threshold, as opposed to just "visible" hours. "Visible" sunshine, for example, occurs around sunrise and sunset, but is not strong enough to excite the sensor. Measurement is performed by instruments called sunshine recorders. For the specific purpose of sunshine duration recording, Campbell–Stokes recorders are used, which use a spherical glass lens to focus the sun rays on a specially designed tape. When the intensity exceeds a pre-determined threshold, the tape burns. The total length of the burn trace is proportional to the number of bright hours. Another type of recorder is the Jordan sunshine recorder. Newer, electronic recorders have more stable sensitivity than that of the paper tape. In order to harmonize the data measured worldwide, in 1962 the World Meteorological Organization (WMO) defined a standardized design of the Campbell–Stokes recorder, called an Interim Reference Sunshine Recorder (IRSR). In 2003, the sunshine duration was finally defined as the period during which direct solar irradiance exceeds a threshold value of 120 W/m². Sunshine duration follows a general geographic pattern: dry areas in the subtropical latitudes (about 25° to 40° north/south) have the highest sunshine values, because these are the locations of the eastern sides of the subtropical high pressure systems, associated with the large-scale descent of air from the upper-level tropopause. Many of the world's driest climates are found adjacent to the eastern sides of the subtropical highs, which bring very high atmospheric stability, little convective overturning, and very low moisture and cloud cover. Desert regions, with nearly constant high pressure aloft and rare condensation—like North Africa, the Southwestern United States, Western Australia, and the Middle East—are examples of hot, sunny, dry climates where sunshine duration values are very high. The sky is clear in these regions, and fair weather is virtually perpetual. The descending branch of the Hadley cell and the long-term lack of atmospheric disturbances helps to explain the seemingly endless supply of sunny, cloud-free days in the deserts. Low clouding conditions are usually associated with rainfall shortage, as seen in these dry regions. The two major areas with the highest sunshine duration, measured as annual average, are the central and the eastern Sahara Desert—covering vast, mainly desert countries such as Egypt, Sudan, Libya, Chad, and Niger—and the Southwestern United States (Arizona, California, Nevada). The city claiming the official title of the sunniest in the world is Yuma, Arizona, with over 4,000 hours (about 91% of daylight time) of bright sunshine annually, but many climatological books suggest there may be sunnier areas in North Africa. In the belt encompassing northern Chad and the Tibesti Mountains, northern Sudan, southern Libya, and Upper Egypt, annual sunshine duration is estimated at over 4,000 hours. There is also a smaller, isolated area of sunshine maximum in the heart of the western section of the Sahara Desert around the Eglab Massif and the Erg Chech, along the borders of Algeria, Mauritania, and Mali where the 4,000-hour mark is exceeded, too. Some places in the interior of the Arabian Peninsula receive 3,600–3,800 hours of bright sunshine annually. The largest sun-baked region in the world (over 3,000 hours of yearly sunshine) is North Africa. The sunniest month in the world is December in Eastern Antarctica, with almost 23 hours of bright sun daily. Conversely, higher latitudes (above 50° north/south) lying in stormy westerlies have much cloudier and more unstable weather, and often have the lowest values of sunshine duration annually. Temperate oceanic climates like those in northwestern Europe, the western coast of Canada, and areas of New Zealand's South Island are examples of cool, cloudy, wet climates where sunshine duration values are very low. The areas with the lowest sunshine duration annually lie mostly over the polar oceans, as well as parts of northern Europe, southern Alaska, northern Russia, and areas near the Sea of Okhotsk. The cloudiest place in the United States is Cold Bay, Alaska, with an average of 304 days of heavy overcast (covering over 3/4 of the sky). In addition to these polar oceanic climates, certain low-latitude basins enclosed by mountains, like the Sichuan and Taipei Basins, can have sunshine duration as low as 1,000 hours per year, as cold air consistently sinks to form fogs that winds cannot dissipate. Chengdu and Chongqing, with between 1,100 and 1,200 hours of sunshine per year, are the gloomiest cities in the world with populations over 250,000. - "8. Measurement of Sunshine Duration", Guide to Meteorological Instruments and Methods of Observation (PDF), WMO, 2008<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Gerhard Holtkamp, The Sunniest and Darkest Places on Earth, Scilogs<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Definitions for other daily elements, Australian Bureau of Meteorology<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Sunniest places in the world, Current Results.com<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Ranking of cities based on % annual possible sunshine, NOAA, 2004<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Godard, Alain; Tabeaud, Martine (2009), Les climats: Mécanismes, variabilité et répartition (in French), Armand Colin, ISBN 9782200246044CS1 maint: unrecognized language (link)<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Antarctic climatic data<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Cloudiest places in the United States, Current Results.com<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles> - Domrös, Manfred; Peng, Gongbing, The Climate of China, pp. 75–78, ISBN 9783540187684<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>

Crescent ♓ Pisces Moon phase on 1 December 2057 Saturday is Waxing Crescent, 5 days young Moon is in Aquarius.Share this page: twitter facebook linkedin Previous main lunar phase is the New Moon before 4 days on 26 November 2057 at 14:22. Moon rises in the morning and sets in the evening. It is visible toward the southwest in early evening. Moon is passing about ∠17° of ♒ Aquarius tropical zodiac sector. Lunar disc appears visually 0.3% wider than solar disc. Moon and Sun apparent angular diameters are ∠1953" and ∠1946". Next Full Moon is the Cold Moon of December 2057 after 9 days on 11 December 2057 at 00:46. There is low ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at big angle, so their combined tidal force is weak. The Moon is 5 days young. Earth's natural satellite is moving from the beginning to the first part of current synodic month. This is lunation 716 of Meeus index or 1669 from Brown series. Length of current 716 lunation is 29 days, 11 hours and 1 minute. It is 8 minutes longer than next lunation 717 length. Length of current synodic month is 1 hour and 44 minutes shorter than the mean length of synodic month, but it is still 4 hours and 25 minutes longer, compared to 21st century shortest. This lunation true anomaly is ∠339°. At the beginning of next synodic month true anomaly will be ∠355.4°. The length of upcoming synodic months will keep decreasing since the true anomaly gets closer to the value of New Moon at point of perigee (∠0° or ∠360°). 3 days after point of perigee on 27 November 2057 at 20:20 in ♐ Sagittarius. The lunar orbit is getting wider, while the Moon is moving outward the Earth. It will keep this direction for the next 11 days, until it get to the point of next apogee on 13 December 2057 at 06:08 in ♋ Cancer. Moon is 367 112 km (228 113 mi) away from Earth on this date. Moon moves farther next 11 days until apogee, when Earth-Moon distance will reach 406 205 km (252 404 mi). 3 days after its descending node on 27 November 2057 at 21:30 in ♐ Sagittarius, the Moon is following the southern part of its orbit for the next 9 days, until it will cross the ecliptic from South to North in ascending node on 11 December 2057 at 10:23 in ♊ Gemini. 17 days after beginning of current draconic month in ♊ Gemini, the Moon is moving from the second to the final part of it. 2 days after previous South standstill on 29 November 2057 at 01:11 in ♑ Capricorn, when Moon has reached southern declination of ∠-24.511°. Next 11 days the lunar orbit moves northward to face North declination of ∠24.523° in the next northern standstill on 12 December 2057 at 21:42 in ♋ Cancer. After 9 days on 11 December 2057 at 00:46 in ♊ Gemini, the Moon will be in Full Moon geocentric opposition with the Sun and this alignment forms next Sun-Earth-Moon syzygy.

In the News The Voyager 2 spacecraft, launched in 1977, hasreached interstellar space, a region beyond the heliosphere – the protective bubble of particles and magnetic fields created by the Sun – where the only other human-made object is its twin, Voyager 1. The achievement means new opportunities for scientists to study this mysterious region. And for educators, it’s a chance to get students exploring the scale and anatomy of our solar system, plus the engineering and math required for such an epic journey. How They Did It Launched just 16 days apart, Voyager 1 and Voyager 2 were designed to take advantage of a rare alignment of the outer planets that only occurs once every 176 years. Their trajectorytook them by the outer planets, where they captured never-before-seen images. They were also able to steal a little momentum from Jupiter and Saturn that helped send them on a path toward interstellar space. This “gravity assist” gave the spacecraft a velocity boost without expending any fuel. Though both spacecraft were destined for interstellar space, they followed slightly different trajectories. Voyager 1 followed a path that enabled it to fly by Jupiter in 1979, discovering the gas giant’s rings. It continued on for a 1980 close encounter with Saturn’s moon Titan before a gravity assist from Saturn hurled it above the plane of the solar system and out toward interstellar space. After Voyager 2 visited Jupiter in 1979 and Saturn in 1981, it continued on to encounter Uranus in 1986, where it obtained another assist. Its last planetary visit before heading out of the solar system was Neptune in 1989, where the gas giant’s gravity sent the probe in a southward direction toward interstellar space. Since the end of its prime mission at Neptune, Voyager 2 has been using its onboard instruments to continue sensing the environment around it, communicating data back to scientists on Earth. It was this data that scientists used to determine Voyager 2 had entered interstellar space. How We Know Interstellar space, the region between the stars, is beyond the influence of the solar wind, charged particles emanating from the Sun, and before the influence of the stellar wind of another star. One hint that Voyager 2 was nearing interstellar space came in late August when the Cosmic Ray Subsystem, an instrument that measures cosmic rays coming from the Sun and galactic cosmic rays coming from outside our solar system, measured an increase in galactic cosmic rayshitting the spacecraft. Then on November 5, the instrument detected a sharp decrease in high energy particles from the Sun. That downward trend continued over the following weeks. The data from the cosmic ray instrument provided strong evidence that Voyager 2 had entered interstellar space because its twin had returned similar data when it crossed the boundary of the heliosheath. But the most compelling evidence came from its Plasma Science Experiment – an instrument that had stopped working on Voyager 1 in 1980. Until recently, the space surrounding Voyager 2 was filled mostly with plasma flowing out from our Sun. This outflow, called the solar wind, creates a bubble, the heliosphere, that envelopes all the planets in our solar system. Voyager 2’s Plasma Science Experiment can detect the speed, density, temperature, pressure and flux of that solar wind. On the same day that the spacecraft’s cosmic ray instrument detected a steep decline in the number of solar energetic particles, the plasma science instrument observed a decline in the speed of the solar wind. Since that date, the plasma instrument has observed no solar wind flow in the environment around Voyager 2, which makes mission scientists confident the probe has entered interstellar space. Though the spacecraft have left the heliosphere, Voyager 1 and Voyager 2 have not yet left the solar system, and won’t be leaving anytime soon. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, a collection of small objects that are still under the influence of the Sun’s gravity. The width of the Oort Cloud is not known precisely, but it is estimated to begin at about 1,000 astronomical units from the Sun and extend to about 100,000 AU. (One astronomical unit, or AU, is the distance from the Sun to Earth.) It will take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud and possibly 30,000 years to fly beyond it. By that time, both Voyager spacecraft will be completely out of the hydrazine fuel used to point them toward Earth (to send and receive data) and their power sources will have decayed beyond their usable lifetime. Why It’s Important Since the Voyager spacecraft launched more than 40 years ago, no other NASA missions have encountered as many planets (some of which had never been visited) and continued making science observations from such great distances. Other spacecraft, such as New Horizons and Pioneer 10 and 11, will eventually make it to interstellar space, but we will have no data from them to confirm their arrival or explore the region because their instruments already have or will have shut off by then. Interstellar space is a region that’s still mysterious because until 2012, when Voyager 1 arrived there, no spacecraft had visited it. Now, data from Voyager 2 will help add to scientists’ growing understanding of the region. Scientists are hoping to continue using Voyager 2’s plasma science instrument to study the properties of the ionized gases, or plasma, that exist in the interstellar medium by making direct measurements of the plasma density and temperature. This new data may shed more light on the evolution of our solar neighborhood and will most certainly provide a window into the exciting unexplored region of interstellar space, improving our understanding of space and our place in it. As power wanes on Voyager 2, scientists will have to make tough choices about which instruments to keep turned on. Further complicating the situation is the freezing cold temperature at which the spacecraft is currently operating – perilously close to the freezing point of its hydrazine fuel. But for as long as both Voyager spacecraft are able to maintain power and communication, we will continue to learn about the uncharted territory of interstellar space. By Ota Lutz Ota Lutz is a STEM elementary and secondary education specialist at NASA’s Jet Propulsion Laboratory. ..Voyager computer technology…………. …………………..w

Nothing stands still. Everything evolves. So why shouldn’t Saturn’s kookie, clumpy F ring put on a new face from time to time? A recent NASA-funded study compared the F ring’s appearance in six years of observations by the Cassini mission to its appearance during the Saturn flybys of NASA’s Voyager mission, 30 years earlier. While the F ring has always displayed clumps of icy matter, the study team found that the number of bright clumps has nose-dived since the Voyager space probes saw them routinely during their brief flybys 30 years ago. Cassini spied only two of the features during a six-year period. Scientists have long suspected that moonlets up to 3 miles (5 km) wide hiding in the F ring are responsible for its uneven texture. Kinks and knots appear and disappear within months compared to the years of observation needed changes in many of the other rings. “Saturn’s F ring looks fundamentally different from the time of Voyager to the Cassini era,” said Robert French of the SETI Institute in Mountain View, California, who led the study along with SETI Principal Investigator Mark Showalter. “It makes for an irresistible mystery for us to investigate.” Because the moonlets lie close to the ring and cross through it every orbit, the research team hypothesizes that the clumps are created when they crash into and pulverize smaller ring particles during each pass. They suspect that the decline in the number of exceptionally bright kinks and the clumps echoes a decline in the number of moonlets available to do the job. So what happened between Voyager and Cassini? Blame it on Prometheus. The F ring circles Saturn at a delicate point called the Roche Limit. Any moons orbiting closer than the limit would be torn apart by Saturn’s gravitational force. “Material at this distance from Saturn can’t decide whether it wants to remain as a ring or coalesce to form a moon,” said French. “Prometheus orbits just inside the F ring, and adds to the pandemonium by stirring up the ring particles, sometimes leading to the creation of moonlets, and sometimes leading to their destruction.” Every 17 years the orbit of Prometheus aligns with the orbit of the F ring in a way that enhances its gravitational influence. The researchers think the alignment spurs the creation of lots of extra moonlets which then go crashing into the ring, creating bright clumps of material as they smash themselves to bits against other ring material. Sounds like a terrifying version of carnival bumper cars. In this scenario, the number of moonlets would gradually drop off until another favorable Prometheus alignment. The Voyagers encounters with Saturn occurred a few years after the 1975 alignment between Prometheus and the F ring, and Cassini was present for the 2009 alignment. Assuming Prometheus has been “working” to build new moons since 2009, we should see the F ring light up once again with bright clumps in the next couple years. Cassini will be watching.

Today’s Wonder of the Day was inspired by Sarah from Houston , TX. Sarah Wonders, “How do the astronauts build a space center in space? ” Thanks for WONDERing with us, Sarah ! What's that up there? Right there! Way up high in the sky, there's a bright dot moving slowly across the black canvas of the heavens. It's way too high to be an airplane, and it's too steady to be a shooting star. What could it be? It's the International Space Station, of course! Visible from Earth with the naked eye, the International Space Station (ISS) is habitable satellite that serves as a microgravity laboratory in space. At costs approaching $150 billion, the ISS is arguably the most expensive thing ever built. It's also the largest structure ever built in space by humans. While aboard the ISS, a rotating crew of international astronauts conducts science experiments in a wide range of disciplines, from astronomy and biology to geology and physics. Astronauts enjoy a sunrise or sunset approximately every 92 minutes, as the ISS completes 15.5 orbits around Earth each day. How can the ISS orbit Earth so quickly? Orbiting at an average altitude of 248 miles above Earth, the ISS travels approximately 17,500 miles per hour. That's a rate of about five miles per second! Over the course of a single day, the ISS travels a distance nearly equal to traveling from Earth to the Moon and back. Despite its speed, the ISS is visible from Earth with the naked eye, as long as you know when and where to look. That's because the ISS is so big. How big? The ISS consists of modules and connecting nodes that house living quarters and laboratories. It also has large exterior trusses for support, as well as more than an acre of solar panels that provide power. In total, the ISS is a little bigger than an American football field. It weighs approximately 900,000 pounds and contains two bathrooms, a gymnasium, and the living space of about a six-bedroom house. So how did such a humongous man-made object get into space? It would be impossible to launch such a huge object with modern technology. That's why the ISS was built slowly, piece-by-piece by a combination of five different space agencies representing 15 different countries. The first piece, Russia's Zarya module, was launched into space in 1998. Over time, other modules were launched via rockets and the United States space shuttle program. Astronauts connected all the pieces over the course of several missions. The ISS has been continuously occupied since November 2000. Since that time, more than 200 astronauts from 15 different countries have visited the ISS. Space agencies hope to continue to use the ISS for many years to come. In fact, there are current plans to add even more modules in coming years.

« PreviousContinue » 8. TO FIND THE DIAMETER OF THE SUN.—(1.) A Very simple method is to hold up a circular piece of paper before the eye at such a distance as exactly to hide the entire disk of the sun. Then we have the proportion, As diet, of paper disk : dist. of sun> disk :: diam. of paper d. : diam. snn's d. (2.) The apparent diameter of the sun, as seen from the earth, is about 32': the apparent diameter of the earth, as seen from the sun, is twice the solar parallax, or 17.88". Thence, the A p. diam. of earth : ap. diam. of can :: real diam. of earth : real diam. of son. (3.) Knowing the apparent diameter of the sun, and its distance from the earth, the real diameter is found by Trigonometry. In figure 95, let S represent the earth, AB the radius of the sun, and ASB half the apparent diameter of the sun. "We shall then have the proportion, AS : AB :: radius : sin. 10' (half mean diam. of sun). By a similar method the diameters of the planeta are obtained. TABLE ILLUSTRATING KEPLER'S THIRD LAW. (CHAMBERS.) In the first column are the relative distances of the planets from the sun; in the second, the periodic times of the planets; and in the third, the squares of the periodic times divided by the cubes of the mean distances. The decimal points are omitted in the third column for convenience of comparison. The want of exact uniformity is doubtless due to errors in the observations. Arago, speaking of Kepler's Laws, says: "These interesting laws, tested for every planet, have been found so perfectly exact, that we do not hesitate to infer the distances of the planet? from the snn from the duration of their sidereal periods; and it is obvious that this method possesses considerable advantages in point of exactness."

Recent studies of the triple star system closest to our solar system, Alpha Centauri, indicate that Centauri A hold slim chances of having formed super-Earth type worlds and only slightly better chances of Earth sized ones ( A Discouraging Look For Centauri A Planets ). But according to Paul Gilster, prospects of finding an Earth type world might be better if we took a closer look at the very closest star to us and the smallest stellar component of the Alpha Centauri System, the M-type red dwarf Proxima Centauri: Today, M dwarf interest grows. There’s at least the chance of a workable ecosystem around such a star, assuming flare activity (common to these stars) might act more as an evolutionary stimulus than a deterrent to life. Moreover, the long lifetimes granted to M dwarfs mean that stable environments could exist for many billions — perhaps hundreds of billions — of years. This is why we’ve seen a recent florescence of M dwarf studies, with a keen interest in their astrobiological prospects, and why Proxima Centauri remains an interesting target. And although it hasn’t gotten the press of its larger siblings, Proxima has generated studies that are closing in on characterizing its system… We can already say this about Proxima planets: If they exist, they are no larger than 0.8 Jupiter masses in the range of orbital periods ranging from one to 600 days. That’s from radial velocity studies published in the late 1990s. This work is now complemented by seven years of high precision radial velocity data gathered with the UVES spectrograph at the European Southern Observatory. Michael Endl (McDonald Observatory) and Martin Kürster (Max-Planck-Institut für Astronomie) address the question of what kind of planets we can exclude from the habitable zone of Proxima Centauri based upon these data. Proxima’s habitable zone, remember, is in close because this is a small star — the authors assume 0.12 solar masses, a reasonable estimate if on the high side, for reasons they explain in their paper. The habitable zone then becomes 0.022 to 0.054 AU, which corresponds to an orbital period ranging from 3.6 to 13.8 days. And the UVES data make it clear that no planet of Neptune mass or larger exists out to a distance of 1 AU. For periods of less than 100 days, no super-Earths are detected larger than about 8.5 Earth masses. And for the actual habitable zone of Proxima Centauri we can rule out planets larger than 2-3 Earth masses in circular orbits. Needless to say, this doesn’t rule out planets of Earth mass or smaller in this zone. Civilian mainstream science is getting better at detecting distant objects around other stars and it’s only a matter of time before an organization like an university or a non-profit discovers an Earth-type world for study. Update: Paul noted I was perhaps too extreme in my analysis of his post, so I made appropriate changes. In fact, he says prospects around Centauri B might be better than expected with improving search methods. When Alpha Centauri is involved, no word is the last one! Corrections duly made Paul, thanks! The last time man set foot on the Moon was in 1972 when Eugene Andrew Cernan, last man on the Moon, boarded the Apollo 17 lunar module. That was 36 years ago and space flight has changed significantly since then, now NASA has more competition, as highlighted by Griffin during a visit to London: “Certainly it is possible that if China wants to put people on the Moon, and if it wishes to do so before the United States, it certainly can. As a matter of technical capability, it absolutely can.” – Dr Michael Griffin As to whether it actually matters whether China are the next to land on the Moon is open to interpretation. After all, the first nation to set foot on Earth’s natural satellite was the USA, so is a return trip a big psychological “victory” for China? “I’m not a psychologist, so I can’t say if it matters or not. That would just be an opinion and I don’t want to air an opinion in an area that I’m not qualified to discuss,” Griffin added. This is more than a mea culpa, it’s a capitulation, as far as a credible civilian space program goes that is. To me, this is proof that our military has already captured the high ground with advanced technology, why else would government mouth-piece Griffin show an obvious ‘could-give-a-shit’ attitude whether China gets to the Moon before Americans get ‘back’ there? Scientists at Brown University in Rhode Island used an instrument aboard a US spacecraft, the Mars Reconnaissance Orbiter, to hunt for traces of phyllosilicates, or clay-like minerals that preserve a record of water’s interaction with rocks. They found phyllosilicates in thousands of places, in valleys, dunes and craters in the ancient southern highlands, pointing to an active role by water in Mars’s earliest geological era, the Noachian period, 4.6 to 3.8 billion years ago. “These results point to a rich diversity of Noachian environments conducive to habitability,” the authors conclude. An intriguing find was of deposits in the pointed peaks at the centre of craters. These peaks are generally taken to be underground material thrown up by an impacting asteroid or comet. For water to be present in such peaks, it must have been present as much as five kilometres (three miles) below the planet’s surface, the paper suggests. “Water must have been creating minerals at depth to get the signatures we see,” head researcher John Mustard, a professor of planetary geology, said in a press release. I never seen the term “Noachian” applied to another planet other than Earth before. Maybe Mars had a race of beings who fell from Grace like humans, only the opposite happened to them, instead of dying in a huge Flood, they died from a massive “dry-off”? Aye, it’s a big Universe Mr. Scott!

Article by Michael Burton, Director of the Armagh Observatory and Planetarium Our view of the cosmos is biased by the vista that is apparent to our eyes. This is what the view in what we call the optically visible portion of the spectrum. To the unaided eye it is a view of a universe full of stars, together with five planets, one Moon and of course the Sun. When augmented with a telescope, our eyes can then see a universe full of galaxies – giant cities of stars. Yet this is not a representative view of the universe. It misses many types of astronomical objects. The electromagnetic spectrum stretches from low energy radio waves to extremely high energy gamma rays. Optical light takes up just a tiny portion of this spectrum, from blue light with a wavelength of 0.4 microns, to red light with a wavelength of 0.7 microns. A micron is a millionth of a metre, and to give that some perspective, the typical human hair is about 50 microns thick. So very small! Evolution has given us eyes responsive to optical light as this is the dominant portion of the electromagnetic spectrum emitted by our local star, the Sun. Our atmosphere, by good fortune, also happens to be transparent to optical radiation. So not only do the Sun’s rays reach us direct, so too does the light from the stars in the sky. If our eyes had evolved to be sensitive to infrared light, for instance, radiation of slightly longer wavelength to optical light, they would have been sensitive to the heat emitted by objects. We would have been able to see in the “dark”. However, we would also have been largely unaware of the spectacle of the starry sky. For the Earth’s atmosphere also emits strongly in the infrared, so drowning out the weaker infrared light that comes from the stars. It is interesting to speculate how civilisation might have evolved in such conditions, without the vista of the night sky that ultimately stirred the development of the scientific methodology that underpins our modern, technologically-based society. There is another region of the spectrum where radiation can reach us directly from distant objects in the cosmos. That is in the radio wavebands. Radiation with wavelengths from about 1cm to 10m can pass largely unobstructed through the atmosphere and so be detected by telescopes on the ground. Radio astronomy is concerned with the measurement of such radiation and then using it to better understand the nature of celestial objects. We are used to receiving radio signals broadcast by TV and radio stations. However it was a great surprise when, in 1933, Karl Jansky detected radio emission from space. Using a radio antenna that he built that is not unlike, in design, that now used for TV aerials, he was investigating the static interference in radio transmissions. In doing so he unexpectedly discovered a radio source of cosmic origin coming from the direction of the centre of our Galaxy. While some radio telescopes of today still do look a bit like Jansky’s original antenna – arrays of dipoles sensitive to the longest wavelength radiation – most radio telescopes now look much closer to optical telescopes in form. Except that they are (generally) far, far bigger! Size is essential for a radio telescope if image clarity is desired. For the image resolution that any telescope can achieve is directly proportional to the wavelength of the radiation being measured, divided by the diameter of the telescope. Since radio waves are over a million times longer than optical waves, this means a radio telescope would have to be a million times larger to achieve the same image quality! Actually it is more complicated than this because the atmosphere blurs the quality of optical images. Radio telescopes can also be combined together to achieve the resolution of a single telescope whose diameter is the size of their distance apart, a technique known as interferometry. Though the sensitivity is only the equivalent of the collecting area of the individual dishes, not the area they are spread over. Nevertheless, radio astronomers have been able to achieve remarkable fidelity in their best images, far better than that of the best optical images obtained of astronomical sources. While optical astronomy is largely concerned with the study of stars, which emit much of their radiation in these bands, radio astronomy is mostly concerned with studying the gas of interstellar and intergalactic space. Very few stars emit significant amounts of radio emission. However, clouds of gas in space are prolific emitters of radio waves. Clouds of atomic gas – largely hydrogen atoms in space – emit radiation with a wavelength of 21 cm. Molecules emit radiation of higher frequency (and shorter wavelength). For instance, the carbon monoxide molecule emits at a wavelength of 3 mm. Its measurement allows us to study the regions where stars form in our Galaxy, the cores of giant molecular clouds found mostly in the central plane of our Galaxy. [Note: carbon monoxide is the second most common molecule in space. However the vastly more abundant hydrogen molecule does not, in general, emit radiation, so it cannot be studied directly in space except in special circumstances]. Finally the hot, ionised gas around luminous stars emits radiation from isolated electrons in the gas, as they swing by the protons. This allows astronomers to study the intense activity and mass loss from these stars, a central part of the process that is recycling material from the stars into the gas that occurs as part of the galactic ecosystem.

Originally shared by Yonatan Zunger We have observed gravitational waves! This morning, the LIGO observatory announced a historic event: for the very first time in history, we have observed a pair of black holes colliding, not by light (which they don't emit), but by the waves in spacetime itself that they form. This is a tremendously big deal, so let me try to explain why. What's a gravitational wave? The easiest way to understand General Relativity is to imagine that the universe is a big trampoline. Imagine a star as a bowling ball, sitting in the middle of it, and a spaceship as a small marble that you're shooting along the trampoline. As the marble approaches the bowling ball, it starts to fall along the stretched surface of the trampoline, and curve towards the ball; depending on how close it passes to the ball and how fast, it might fall and hit it. If you looked at this from above, you wouldn't see the stretching of the trampoline; it would just look black, and like the marble was "attracted" towards the bowling ball. This is basically how gravity works: mass (or energy) stretches out space (and time), and as objects just move in what looks like a straight path to them, they curve towards heavy things, because spacetime itself is bent. That's Einstein's theory of Relativity, first published in 1916, and (prior to today) almost every aspect of it had been verified by experiment. Now imagine that you pick up a bowling ball and drop it, or do something else similarly violent on the trampoline. Not only is the trampoline going to be stretched, but it's going to bounce -- and if you look at it in slow-motion, you'll see ripples flowing along the surface of the trampoline, just like you would if you dropped a bowling ball into a lake. Relativity predicts ripples like that as well, and these are gravitational waves. Until today, they had only been predicted, never seen. (The real math of relativity is a bit more complicated than that of trampolines, and for example gravitational waves stretch space and time in very distinctive patterns: if you held a T-square up and a gravitational wave hit it head-on, you would see first one leg compress and the other stretch, then the other way round) The challenge with seeing gravitational waves is that gravity is very weak (after all, it takes the entire mass of the Earth to hold you down!) and so you need a really large event to emit enough gravity waves to see it. Say, two black holes colliding off-center with each other. So how do we see them? We use a trick called laser interferometry, which is basically a fancy T-square. What you do is you take a laser beam, split it in two, and let each beam fly down the length of a large L. At the end of the leg, it hits a mirror and bounces back, and you recombine the two beams. The trick is this: lasers (unlike other forms of light) form very neat wave patterns, where the light is just a single, perfectly regular, wave. When the two beams recombine, you therefore have two overlapping waves -- and if you've ever watched two ripples collide, you'll notice that when waves overlap, they cancel in spots and reinforce each other in spots. As a result, if the relative length of the legs of the L changes, the amount of cancellation will change -- and so, by monitoring the brightness of the re-merged light, you can see if something changed the length of one leg and not the other. LIGO (the Laser Interferometer Gravitational-Wave Observatory) consists of a pair of these, one in Livingston, Louisiana, and one in Hartford, Washington, three thousand kilometers apart. Each leg of each L is four kilometers long, and they are isolated from ambient ground motion and vibration by a truly impressive set of systems. If a gravitational wave were to strike LIGO, it would create a very characteristic compression and expansion pattern first in one L, then the other. By comparing the difference between the two, and looking for that very distinctive pattern, you could spot gravity waves. How sensitive is this? If you change the relative length of the legs of an L by a fraction of the wavelength of the light, you change the brightness of the merged light by a predictable amount. Since measuring the brightness of light is something we're really good at (think high-quality photo-sensors), we can spot very small fractions of a wavelength. In fact, the LIGO detector can currently spot changes of one attometer (10⁻¹⁸ of a meter), or about one-thousandth the size of an atomic nucleus. (Or one hundred-millionth the size of an atom!) It's expected that we'll be able to improve that by a factor of three in the next few years. With a four-kilometer leg, this means that LIGO can spot changes in length of about one-quarter of a part in 10²¹. That's the resolution you need to spot events like this: despite the tremendous violence of the collision (as I'll explain in a second), it was so far away -- really, on the other end of the universe -- that it only created vibrations of about five parts in 10²¹ on Earth. So what did LIGO see? About 1.5 billion light years away, two black holes -- one weighing about 29 times as much as the Sun, the other 36 -- collided with each other. As they drew closer, their gravity caused them to start to spiral inwards towards each other, so that in the final moments before the collision they started spinning around each other more and more quickly, up to a peak speed of 250 orbits per second. This started to fling gravity waves in all directions with great vigor, and when they finally collided, they formed a single black hole, 62 times the mass of the Sun. The difference -- three solar masses -- was all released in the form of pure energy. Within those final few milliseconds, the collision was 50 times brighter than the entire rest of the universe combined. All of that energy was emitted in the form of gravitational waves: something to which we were completely blind until today. Are we sure about that? High-energy physics has become known for extreme paranoia about the quality of its data. The confidence level required to declare a "discovery" in this field is technically known as 5σ, translating to a confidence level of 99.99994%. That takes into account statistical anomalies and so on, but you should take much more care when dealing with big-deal discoveries; LIGO does all sorts of things for that. For example, their computers are set up to routinely inject false signals into the data, and they don't "open up the box" to reveal whether a signal was real or faked until after the entire team has finished analyzing the data. (This lets you know that your system would detect a real signal, and it has the added benefit that the people doing the data analysis never know if it's the real thing or not when they're doing the analysis -- helping to counter any unconscious tendency to bias the data towards "yes, it's really real!") There are all sorts of other tricks like that, and generally LIGO is known for the best practices of data analysis basically anywhere. From the analysis, they found a confidence level of 5.1σ -- enough to count as a confirmed discovery of a new physical phenomenon. (That's equal to a p-value of 3.4*10⁻⁷, for those of you from fields that use those) So why is this important? Well, first of all, we just observed a new physical phenomenon for the first time, and confirmed the last major part of Einstein's theory. Which is pretty cool in its own right. But as of today, LIGO is no longer just a physics experiment: it is now an astronomical observatory. This is the first gravity-wave telescope, and it's going to let us answer questions that we could only dream about before. Consider that the collision we saw emitted a tremendous amount of energy, brighter than everything else in the sky combined, and yet we were blind to it. How many more such collisions are happening? How does the flow of energy via gravitational wave shape the structure of galaxies, of galactic clusters, of the universe as a whole? How often do black holes collide, and how do they do it? Are there ultramassive black holes which shape the movement of entire galactic clusters, the way that supermassive ones shape the movement of galaxies, but which we can't see using ordinary light at all, because they aren't closely surrounded by stars? Today's discovery is more than just a milestone in physics: it's the opening act of a much bigger step forward. LIGO is going to keep observing! We may also revisit an old plan (scrapped when the politics broke down) for another observatory called LISA, which instead of using two four-kilometer L's on the Earth, consists of a big triangle of lasers, with their vertices on three satellites orbiting the Sun. The LISA observatory (and yes, this is actually possible with modern technology) would be able to observe motions of roughly the same size as LIGO -- one attometer -- but as a fraction of a leg five million kilometers long. That gives us, shall we say, one hell of a lot better resolution. And because it doesn't have to be shielded from things like the vibrations of passing trucks, in many ways it's actually simpler than LIGO. (The LISA Pathfinder mission, a test satellite to debug many of these things, was launched on December 3rd) The next twenty years are likely to lead to a steady stream of discoveries from these observatories: it's the first time we've had a fundamentally new kind of telescope in quite a while. (The last major shift in this was probably Hubble, our first optical telescope in space, above all the problems of the atmosphere) The one catch is that LIGO and LISA don't produce pretty pictures; you can think of LIGO as a gravity-wave camera that has exactly two pixels. If the wave hits Louisiana first, it came from the south; if it hits Washington first, it came from the north. (This one came from the south, incidentally; it hit Louisiana seven milliseconds before Washington) It's the shift in the pixels over time that lets us see things, but it's not going to look very visually dramatic. We'll have to wait quite some time until we can figure out how to build a gravitational wave telescope that can show us a clear image of the sky in these waves; but even before that, we'll be able to tease out the details of distant events of a scale hard to imagine. You can read the full paper at http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102 , including all of the technical details. Many congratulations to the entire LIGO team: you've really done it. Amazing. Incidentally, Physical Review Letters normally has a strict four-page max; the fact that they were willing to give this article sixteen pages shows just how big a deal this is.

There may be three times as many stars in the known universe as the number previously calculated, according to new research done at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. Astronomers have until now used as a yardstick the number of brown dwarfs in our own Milky Way Galaxy to calculate the number of stars in all the other galaxies, but that yardstick may not be reliable. Brown dwarfs are mass-heavy bodies too large to be a planet, yet too small to sustain the stable nuclear fusion of a real star; they are larger but in some ways comparable to Jupiter*—they simply have –never “ignited”, so to speak, and thus do not emit light like real stars. For this reason, they are difficult to spot, and their presence must be deduced by the effect of their gravitational “lensing”, or bending of the passing starlight coming from the stars behind them (in the same way that science is deducing the presence of Earth-like planets). Astronomers have established with reasonable certainty that the ratio of brown dwarfs to real stars in our Milky Way Galaxy is roughly 100 invisible dwarfs to one actual star, and until now, it was believed that that ratio applied to all galaxies. However, the Milky Way is a spiral-shaped galaxy, and the new research has shown that in the eight elliptical galaxies there are many more brown dwarfs per full star, on the order of 1,000-2,000 to one; considering that the known universe is composed of one third elliptical galaxies, this newly discovered ratio, extrapolated outward, gives us the new presumptive estimate of “at least” three times as many stars universe-wide as previously thought. This new template, if true, will also mean that the galaxies have a much greater mass, and that they developed earlier and faster than the standard Big Bang model can account for. If the standard model cannot account for the greater mass, what can explain it? We are told in The Book of Knowledge: The Keys of Enoch® by J.J. Hurtak, PhD., that “ “our universe began on a spiral” rather than in a steady state or “Big Bang” position.” (See Key 109). As the mysteries of creation seem to deepen with every discovery, we move forward in the expectation that we will ultimately attain “mastery over mystery”, and that the sciences of the Earth will be brought into phase with the unimaginably vast and poetic beauty of creation. *Note: Although Jupiter is indeed a huge planet with a great mass, it is not considered to be a brown dwarf. However, some astrophysicists have for decades believed that it possesses the potential for future “stardom”—that is, it is not a static body but a very energetic one, host to many dynamic processes, and is continually absorbing more mass from the incoming comets and other space debris which it attracts with its strong gravitational pull (as in the spectacular crash of Comet Levy-Shoemaker); it has been speculated by Arthur C. Clarke, among others, that Jupiter could actually at some point accumulate enough mass to see the initiation of a reactor state and become a real star. Image: A Leonids Star Field Link to article from the New York Times regarding new research:

When even the largest telescope in the world is too small, interferometry can go further When we talk about the size of an optical telescope, like those found at ESO’s Paranal Observatory, we are really referring to the diameter of its primary mirror. The larger the mirror diameter, the higher its resolution — that is, the better its ability to pick out fine detail. The atmosphere degrades this ability, but adaptive optics can partially compensate for this. However, even with the largest telescopes available today, many astronomical objects still just look like a small dot in space. For example, to see details on the surface of one of our neighbouring stars, we would need a telescope with a mirror more than 1.5 kilometres in diameter! Building mirrors larger than a few metres in diameter is both expensive and difficult as the mirror’s own weight causes it to sag and deform due to the effects of gravity. The use of an active optics system below the mirror to control and compensate for flexures has meant that telescope designers have been able to make the jump from telescopes in the 4-metre class, like the NTT, to the current 8- to 10-metre generation of optical telescopes, like the VLT. Using segmented mirrors, the size limit can be pushed back to a few tens of metres. The planned ELT will have a mirror that is 39 metres in diameter. However, even this is still too small to see the details on the surface of even a nearby star! For radio astronomy, the fine details are even more difficult to resolve. At an equivalent diameter, a radio telescope has a resolution 1000 times worse than a visible-light telescope simply because radio waves such as those observed by ALMA, are much longer — around 1 millimetre — than those observed by optical telescopes, which have wavelengths of around one thousandth of a millimetre, or 1 micrometre. The longer the wavelength, the lower, and worse, the resolution you can obtain. To be able to pick out the same features as the VLT, a single radio dish with a diameter of several kilometres would be needed. Astronomers’ hunger for higher resolution led to the application of a new technology called interferometry, first used at radio wavelengths to observe the Sun back in 1946. So, how does interferometry work? An interferometer combines the light from two or more telescopes, allowing astronomers to pick out the details of an object as though they are being observed using mirrors or antennas measuring hundreds of metres in diameter. The distance between two telescopes, also known as the separation, forms a baseline, which is effectively the diameter of the “virtual” telescope created by the interferometry. When the light from several telescopes is being used the separations between each pair of telescopes each constitute a different baseline, and the effective telescope diameter corresponds to the greatest separation in the array. The more baselines we use, the more information we acquire about an object as each distinct baseline reveals a different piece of the information jigsaw that makes up a complete image. You can think about this in musical terms: if the image of an astronomical object represents the complete song, then each baseline represents the individual notes that make up the piece. The more baselines we have, the more notes we get, and the more complete our version of the song is. Furthermore, as the Earth rotates, the orientation of the various baselines with respect to the observed object changes, resulting in the acquisition of more information. So the more telescopes we use, the more baselines and information we can acquire. This is the case for both optical and radio interferometry. Combining the four Unit Telescopes (UTs) of the VLT gives us six baselines. This is the reason for the strange arrangement of the telescopes on the platform: the lengths and orientations of the six baselines are all different. In principle, the UTs can obtain a resolution equivalent to a telescope 130 metres in diameter, which corresponds to its largest available baseline. The VLT Interferometer (VLTI) can also make use of four 1.8-metre Auxiliary Telescopes (ATs) that can be moved along the platform to get more information about the object. With the ATs, the VLTI can go even further, with a maximum resolution equivalent to a telescope of 200 metres in diameter and a much larger number of possible baselines. This is an improvement of up to 25 times on the resolution of a single VLT Unit Telescope. The VLTI gives astronomers the ability to study celestial objects in unprecedented detail. It is possible to see details on the surfaces of stars, and even to study the environment close to a black hole. The VLTI has allowed astronomers to obtain one of the sharpest images ever of a star, with a spatial resolution of only 4 milliarcseconds. This is equivalent to picking out the head of a screw at a distance of 300 kilometres! ALMA array from the air. Credit: Clem & Adri Bacri-Normier (wingsforscience.com)/ESO In radio interferometry, ALMA is leading its own revolution. With the potential to combine up to 66 antennas with 1225 baselines, and a maximum distance between the antennas of 16 kilometres… Well, you do the maths! ALMA has by far the highest resolution available to any radio astronomer, up to ten times better than that achieved by the NASA/ESA Hubble Space Telescope. Each telescope involved in interferometry observes the same astronomical object, and each picks up some of the light that it emits. However, interferometry only works if the light received by each telescope is successfully combined. Referring back to our musical analogy, we must collect the individual musical notes and combine them in order to acquire the complete song. However, due to how the light waves from the object travel both through space and through the Earth’s atmosphere, they arrive at each telescope at slightly different times. So when the beams are combined each interferometer needs a system to compensate for these tiny time differences in order to ensure that all light beams reach the detector at the same time. In the case of ALMA, radio waves are combined electronically inside the powerful computer called a correlator. Longer wavelengths are easier to combine, which is the reason why radio interferometry developed long before optical. Shorter wavelengths, like those observed by the VLT, are a completely different story. Even supercomputers like the ALMA correlator are simply not capable of reaching the level of precision needed to successfully combine signals in the infrared domain. It took decades to develop a reliable system for infrared interferometry, like the one used at the VLTI. Instead of a supercomputer, optical/infrared interferometry uses a system of underground tunnels, known as delay lines, These delay lines add a little extra distance into the paths travelled by the earliest arriving waves, introducing compensatory time delays that ensure that all the light waves from the object can be combined correctly. This is achieved by a system of several carriages with mirrors that can move along rails that are the same length as the maximum baseline. By careful positioning of these carriages the incoming signals can be fine-tuned, entering the instrument with an astonishing precision of 1/1000 mm. So what does the combined light look like? Not very fancy really. Imagine a perfectly still pond and then think of dropping two pebbles into it side by side. Each pebble produces an expanding system of circular ripples, and at some point the two sets of ripples will begin to overlap. Where two wave crests or troughs of the ripples meet, the height of the wave doubles. However, if the crest of one wave meets the trough of another, they cancel each other out. If we swap water for light (an electromagnetic wave), the interaction of the two sets of ripples is known as interference. In this picture the French ESO astronomer Jean-Baptiste Le Bouquin is demonstrating how waves — not light waves, but water waves — can combine, or interfere, to create larger waves. Credit: ESO/M. Alexander Such an interference pattern is similar to the pattern of light and dark stripes (known as interference fringes) that you can see by doing a double slit experiment. The separation and the contrast of the fringes depend on the size and shape of the object observed. Furthermore, the interference pattern can be observed at different wavelengths (colours), or even over a whole wavelength range, as with spectroscopy. In the early days of interferometry, the limited number of baselines only revealed whether the object was a single source, a double source or extended doubles, but an actual image was unthinkable. Now, the use of highly sophisticated interferometers like ALMA, coupled with a dose of mathematics, mean that astronomers can produce a picture almost as detailed as the one obtained with a full-size mirror hundreds of metres in diameter or a giant antenna several kilometres wide. Thinking again of the notes in a piece of music, one could say that interferometry is truly revealing the harmony of the Universe. Science Highlights with Interferometry - MIDI clearly resolves star WOH G64 to discover it is not as big as previously thought! (eso0815) - VLTI detects exo-zodiacal light using PIONIER (eso1435) - Revolutionary ALMA image reveals planetary Genesis (eso1436) - VLTI finds dust at unexpected places above and below the plane of the disk surrounding the supermassive black hole in an active galaxy (eso1327) - VLTI detects a very small companion in the protoplanetary disk around the star T Cha (eso1106) - More images related to ESO interferometry - ‘ESOcast 13: A sharper view of the Universe with the VLT Interferometer’ gives a great video overview of the methods described here.

A team of UK scientists have traced the origins of mysterious “alien signals” to a galaxy six billion light years away. Seventeen “fast radio bursts” (FRBs) recorded since 2007 are believed to show proof of extraterrestrial intelligence, and scientists have been busy researching their origins for the last nine years. The cause of the bursts is still unknown, but scientists say they emit as much energy as the sun emits in 10,000 years. Astronomer Evan Keane from the UK’s Jodrell Bank Observatory, who led the scientific team that published the new findings in the journal Nature, was able to record one of the most recent radio burst called FRB 150418 on April 18, 2015 with the help of the Parkes radio telescope in Australia. It lasted less than one millisecond, the shortest of them all. The process of pinpointing its location was long. First Australia’s telescope located the radio afterglow in space and then a second 8.2-meter-long telescope in Hawaii, known as the Subaru Telescope, helped trace the origin of the wave to an elliptical galaxy, which is an off-spherical concentration of stars believed to be relatively old. Some have speculated that the bursts could be a signal sent by extraterrestrial intelligence. “Nope! Sorry,” Keane said in response to this theory, as quoted by AFP. The radio waves most likely originate from two colliding neutron stars, which at some point were orbiting each other before merging, according to Keane. Due to the composition of the galaxy, it is more likely that a collision of two dead stars caused the radio bursts, rather than the explosion of a supernova, astronomers say. Keane is now working with his team to determine how much material the radio wave passed through before being recorded on Earth. According to the astronomer, this could answer some of the biggest scientific mysteries, such as the measurements of the cosmic microwave background. Scientists plan to use such radio bursts in the future to create a map that could help detail the magnetic fields between various galaxies and determine what type of matter exists in space. The discovery might also shed some light on the “missing matter question” question. Scientists believe that the universe consists of 70 percent dark energy, 25 percent undetermined dark matter, and around five percent ordinary matter or, more specifically, what planets and stars are made of. Astronomers are currently only able to identify half of the ordinary matter, while the other half is labelled as “missing matter.”

Super-Earths. They’re so hot right now. Super-Earths. They are the most abundant type of planet (that we know of) in the Galaxy. About half of all Sun-like stars have one. Many stars have a bunch: up to seven have been found orbiting a single star. The Kepler space telescope has opened the Super-Earth floodgates. Yet Super-Earths are a mystery. How did they get there? And if they are so common, why don’t we have any in the Solar System? In this post I will describe a new model we’ve built for the origin of super-Earths. I’ll also explain how the Solar System might fit into this picture. The setting: a pristine disk of gas and dust orbiting a baby star. This is where planets form, and they form fast. These planet nurseries only last a few million years before the gas evaporates. (A few million years may seem like a long time, but remember that the Galaxy is 13 billion years old, so this is very short from that point of view.) Our idea is a simple three-step process: - Large (Mars- to Earth-sized) bodies grow out where it is cold enough that ice is a building block (past the snow line). These planetary embryos are massive enough to launch waves in the disk. The waves push back on the embryos’ orbits and push the embryos slowly toward the star. This is orbital migration. - Embryos don’t migrate all the way onto the star because the disk has an inner edge that stops them. The first embryo reaches the inner edge. Later embryos migrate inward toward the first one but they don’t just collide. Instead, they are trapped in orbital resonances. The orbits of neighboring embryos have a special setup, where they re-align every so often. Resonances are measured by the ratio of the orbital periods of neighbors. For example, the 2:1 resonance means that for every 2 orbits of the inner planet, the outer one completes 1 orbit. The embryos end up in a resonant chain, where each pair of neighbors is in resonance. - The gas disk — which was holding the embryos’ hands while they sat in a resonant chain — evaporates. With no gas, the resonant chain of embryos goes unstable about 90-95% of the time. There is a phase of giant collisions (similar to the late phases of growth of our own rocky planets). The survivors are the super-Earths we see, along with the 5-10% of lucky systems in stable resonant chains. Our computer simulations of this process match the actual super-Earths. Simulations always make resonant chains. And when we combine 90-95% of unstable resonant chains with 5-10% stable ones, we match the properties of the super-Earths found by Kepler. A small fraction of super-Earths in resonant chains do exist. These are some of the very prettiest planetary systems out there. For example, the recently-discovered TRAPPIST-1 system (poem here) is a 7-planet resonant chain! Each pair of neighboring planets is in resonance. The 7 planets are in a giant resonant chain that periodically re-aligns. Every 2 orbits of the outermost planet (planet h), planets b, c, d, e, f, and g complete exactly 24, 15, 9, 6, 4, and 3 orbits, respectively, and all seven planets re-align. You can even make music with the orbits of the system (see here). This elegant setup would not occur by chance. Orbital migration is the only way we know of to create such well-behaved systems. Just like children, all systems of super-Earths are beautiful and perfect (resonant chains) when they are born. Unfortunately, once the calming influence of the gas disk is gone (like teachers and parents losing hold), most go unstable. And just like super-Earth systems, at 90-95% of society is made up of people who have survived instability. (And you don’t want to hang around with the 5-10% of stable people anyway.) There is an added bonus. We might be able to explain why the Solar System is different. Remember those planetary embryos? What if, before it migrated too far, the first embryo grew big enough to capture gas from the disk and become a gas giant like Jupiter? Then the story changes. A gas giant carves a gap in the disk and blocks the inward migration of the other embryos. The gas giant holds back the migrating invaders, and protects the inner Solar System. The ice giants Uranus and Neptune, as well as Saturn’s core, may represent “failed super-Earths”, embryos that were trying to migrate in close to the Sun but were blocked by Jupiter. (My more detailed post about this idea here). According to this story, Jupiter’s growth is what caused our Solar System’s evolution to branch away from that of super-Earth systems. What makes our Solar System unusual or special. This is testable, because the idea predicts an anti-correlation between Jupiter-like planets and super-Earth systems. Right now it’s hard to say, but within a few years we should have an answer. A quick recap in image form: PS – A lot of astronomers dislike the term “super-Earth” because we have no idea how similar to Earth these planets are. There are good reasons to think that they are generally not like Earth. Unfortunately, “super-Earth” has caught on. Also, there is no alternative that I find satisfactory (at the moment). So, I’ve run with super-Earth. Sorry if I upset you!

Jan 13, 2016 Speculations on electrical aspects of the sun were common long before Birkeland. The ideas of the Irish-English physicist Osborne Reynolds (1842-1912) marked a further intellectual milestone. In a few little-known articles dated to 1870 and 1871, he suggested that cometary tails are not appendages ‘evaporated’ from the nuclei, but regions of local ‘ether’ illuminated under the electrical influence of the sun – again invoking laboratory work on discharge tubes: “… when electricity, under certain conditions, as in Dr. Geissler’s tubes, is made to traverse exceedingly rare gas, the appearance produced is similar to that of the comets’ tails; the rarer this gas is, the more susceptible is it of such a state, and, so far as we know, there is no limit to the extent of gas that may be so illuminated. Hence we may suppose the exciting cause to be electricity, and the material on which it acts and which fills space to have the same properties as those possessed by gas. What is more, we can conceive the sun to be in such a condition as to produce that influence on this electricity which should cause the tail to occupy the direction it does. For such an electric discharge will be powerfully repelled by any body charged with similar electricity in its neighbourhood. The electricity would be discharged by the comets on account of some influence which the sun may have on them …” “… there is matter in space in the form of gas, and … the comet causes it to be electrically illuminated by a brush …” Like some of his precursors, Reynolds recognised the fundamental affinity between cometary tails, the planetary aurora and the solar corona – in what would today be called glowing plasma: “I think this electrical hypothesis is supported by the, to me, seeming analogy between comets, the corona, and the aurora; an analogy which suggests that they must all be due to the same cause. … The aurora has long been considered as an electric phenomenon, and recently the same effect has been produced by the discharge of electricity of very great intensity through a very rare gas, there being no limit to the space which it will thus traverse. This being so, why should not the tails of comets and the corona also be electric phenomena? Their appearance and behaviour correspond exactly with those of the aurora, and there is surely nothing very difficult in imagining the sun which is the source of so much heat being also the source of some electricity. … it was sufficient to point to the aurora, which is universally admitted to be electrical … electricity may form the tails of comets and the corona.” Reynolds’ characterisation of the luminiferous ether reads exactly like a modern description of cosmic plasma: “… may we not assume that it is the medium which fills space that is illuminated by the electric discharges? … At any rate, it is certain that the appearance of streamers, the rapidity of change and emission, the perfect transparency and the wave-like fluctuations which belong to these phenomena, are all exhibited by the electric brush … I have only to add that the main assumption involved in the electric theory is, that space is occupied by matter having similar electrical properties to those of these … The reasoning I made use of was, essentially à fortiori. I pointed to the fact that the electric brush as seen in the Geissler tubes exhibits similar appearances, and that at the times of greatest display on the part of comets and the aurora similar conditions are present, such as a change in the action of the sun, conditions which, to say nothing more, are favourable to electric disturbance.” Moreover, Reynolds realised that the electrical polarity of these respective systems did not reside in each individually, but was between the sun and the earth or a comet: “It is quite clear that the tail of a comet cannot be due to a discharge between two electrodes situated on the comet itself. In the same way, from the position occupied by the corona, it can hardly be due to electricity passing between two electrodes on the sun. In fact, if a comet’s tail is electrical, it is due to a discharge of electricity of one kind or another from the comet, which, for the time, answers to one of the electrodes only. The same may be said of the corona and the sun. … the sun, acting by evaporation or otherwise, causes continual electric disturbance between the earth and its atmosphere, the solid earth being negatively charged and the atmosphere positively, and … the aurora is the reunion of these electricities taking place in the atmosphere. … If there is a continual electric disturbance between the sun and the medium in which it is placed, so that the sun becomes negatively and the medium positively charged, the reunion of these electricities would form the corona.” Like Herschel before him, Reynolds contemplated the role of electricity in the driving mechanism of solar irradiation: “It must not be supposed that I assume the sun to be a reservoir of electricity which it is continually pouring into space. I consider that the supply of electricity in the sun is kept up by some physical action going on between the sun and the medium of space, whereby the sun becomes negatively charged, and the medium positively. This may be well illustrated by reference to the common electrical machine … Assume, then, that the sun is in the position of the rubber, while the ether is in that of the glass: then the corona corresponds to the spark or brush which leaves the conductor. … If the corona be an electric discharge, the electricity will be continually carrying off some of the elements of the sun into space where they will be deposited and condensed.” While Reynolds may have erred in his hunch that this continuous “stream of matter” from the sun explains the origin of meteors, he certainly intuited the notion of the incessant conveyance of electric fields in the solar wind correctly. Richard Anthony Proctor (1837-1888) was an English astronomer who, in the early 1870s, similarly speculated on matter projected from the sun, the connection between solar prominences and magnetic disturbances on the earth and electrical comets. In a monograph which saw the light of day in 1872, the German astrophysicist Johann Karl Friedrich Zöllner (1834-1882) rehearsed the opinion that comet tails and their directions are ‘a phenomenon of electrical repulsion’, due to ‘free electricity of the solar surface’. Zöllner contended that ‘the assumption of a distant electrical effect of the sun on all its encircling bodies is necessary and sufficient to derive all essential and characteristic appearances of the tails and vaporous shells of the comets.’ This involved ‘a permanent development of electricity on the surface of the sun which is continuously maintained by the processes taking place there’. The American natural historian Jacob Ennis (1807-1890) penned an article entitled ‘The Electric Constitution of the Solar System’, which was published in 1878. In this, he defended a position already encountered above: “The zodiacal light, the aurora borealis, the corona of the sun, and the tails of comets, are all different forms of the same thing. They are electrical brushes, precisely the same as the electric brushes which in the night are seen to fly off from a highly charged electric machine.” Ennis envisioned ‘evaporation’ as the operative mechanism: “On our great globe, on the sun, and on the comets, the electric fluid is developed by evaporation.” On the earth, “the higher regions of the atmosphere are always highly charged with electricity. Ordinarily the ground is negative, and the air is positively electrified. … What becomes of this fluid? … it is driven off in the form of auroral streamers constantly far away into empty space as electrical brushes.” Comets “are easily evaporated and diluted by the sun’s rays; and in this evaporation they evolve unusual amounts of the electric fluid. … It is then, by the repulsion of the sun’s corona, driven backward all around like a fountain away from the sun, and it forms the tail …” And a similar process transpires on the sun: “The corona of the sun consists of brushes of electricity. … They are caused there, as here, by the evaporation from the intense heat of the sun. They are so powerful as to drive the tails of comets, also electric brushes, in the direction away from the sun. They drive away from the direction of the sun our zodiacal light, and our aurora borealis, and aurora australis, all three of which must be regarded as the perpetual tail of our planet, in many respects similar to the tail of a comet … the auroral streamers … point away from the sun, like the tails of comets, driven by the sun’s electric repulsion.” “It is doubtless an effulgence, a constant streaming forth of electricity, like the aurora borealis, or like the zodiacal light, from every part of the sun’s surface. … we can think of it as nothing but an outflow of electricity, an electrical brush, or as thousands of them united. … As evaporation from the sun is millions of times greater than from our earth, so the evolution of electricity may be in proportion. … In appearance and in action there is a perfect identity between our aurora borealis and the corona of the sun. … No one has said that the zodiacal light is electric, and that this and the auroral streamers, always like comets, point away from the sun. No one has regarded all these phenomena as emanating from a common cause: the solar heat causing evaporation. No one has supposed that the far distant solar corona, by mere electric repulsion, drives off the tails of comets, the auroral streamers, and the zodiacal light.” From a modern point of view, Ennis can be said to have conflated the solar corona with the solar wind, insofar as the latter is the direct cause of the spatial distortion of planetary and cometary magnetospheres. Nevertheless, Ennis’ contribution was no small achievement considering that it was made nearly a century before the existence of the solar wind was confirmed empirically. Rens Van Der Sluijs

January brings us striking views of the night skies! You’ll be able to see well known constellations during the long hours of darkness in the Northern hemisphere, with crisp cold skies. This is an ideal time to get out and look at the wonders of the night sky as there is so much to see for the beginner and seasoned astronomer alike. You will only need your eyes to see most of the things in this simple guide, but some objects are best seen through binoculars or a small telescope. So what sights are there in the January night sky and when and where can we see them? As soon as the month starts we receive a welcome treat in the form of the Quadrantid meteor shower on the evening of the 3rd/ morning of the 4th of January. The Quadrantids can be quite an impressive shower with rates (ZHR) of up to 120 meteors per hour at the showers peak (under perfect conditions) and can sometimes produce rates of up to 200 meteors per hour. The peak is quite narrow lasting only a few hours, with activity either side of the peak being quite weak. Due to a waxing gibbous moon, the best time to look is after midnight and through the early hours when the moon sets in time for us to see the peak which is 07:20 UT. The radiant of the Quadrantids (where the meteors radiate from) is in the constellation of Boötes, however many people are mislead in thinking they need to look at the radiant to see the meteors – this is not true. Meteors will come from the radiant, but will appear anywhere in the whole sky at random. You can trace the shooting stars path back to the radiant to confirm if it is a meteor from the meteor shower. For more information on how to observe and enjoy the Quadrantid meteor shower, visit meteorwatch.org Mercury is low down in the southeast before sunrise in the first week of January. Venus will be shining brightly in the southwest until May and will pass within 1° of Neptune the furthest planet on the 12th and 13th of January. You can see this through binoculars or a small telescope. On the 26th Venus and the Moon can be seen together after sunset. On the 5th of January, Earth will be at “Perihelion” its closest point to the Sun. Mars brightens slightly to -0.5 during January and can be found in the tail of Leo; it can be easily spotted with the naked eye. The red Planet is close to the Moon on the night of the 13th/ 14th January. On January 2nd Jupiter and the Moon will be very close to each other with a separation of only 5° with Jupiter just below the Moon. Jupiter will continue to be one of the brightest objects in the sky this month. Saturn now lies in the constellation of Virgo and follows after just after Mars in Leo. Uranus is just barely visible to the naked eye in the constellation of Pisces and can be easily spotted in binoculars or small telescopes throughout the month. The Moon will pass very close to Uranus on the 27th and will be just 5.5° to the left of the planet. - First Quarter – 1st and 31st January - Full Moon – 9th January - Last Quarter – 16th January - New Moon – 23rd January In January the most dominant and one of the best known constellations proudly sits in the south of the sky – Orion the hunter. Easily distinguishable as a torso of a man with a belt of three stars, a sword, club and shield, Orion acts as the centre piece of the surrounding winter constellations. Orion is viewed upside down in the Northern sky as seen from the Southern hemisphere. Orion contains some exciting objects and its most famous are the Great Nebula in Orion(M42), which makes up the sword and is easily seen in binoculars or a telescope and bright Betelgeuse, Orion’s bright alpha star (α Orionis). Betelgeuse is a red supergiant many times larger than our Sun; it would engulf everything in our solar system out to the orbit of Jupiter, if the two stars swapped places. Betelgeuse will eventually end its life in a Supernova explosion and some people believe that it may have already exploded and the light hasn’t reached us yet. It would make for a fantastic sight! If you draw an imaginary line through the three belt stars of Orion and keep going up and to the right, you will come to a bright orange coloured star – Aldebaran (α Tauri) in the constellation of Taurus. Taurus depicts a head of a bull with Aldebaran as its eye with a V shape that creates long horns starting from what we call the Hyades cluster, a V shaped open cluster of stars. If you continue to draw a line through the belt stars of Orion, through Aldebaran and keep going, you will eventually get to one of the gems in Taurus – The Pleiades cluster or Seven Sisters (M45) a stunning cluster of blue and extremely luminous stars and from our vantage point on Earth, the most recognisable cluster with the naked eye. A great object to scan with binoculars. A great object to hunt for with a small telescope is the Crab Nebula (M1) near the end of the lower horn of Taurus. If you go back to our imaginary line drawn through the belt stars of Orion and draw it in the other direction, to left and below, you will come to the very bright star Sirius (α CMa) – The Dog Star in Canis Major. Sirius is the brightest star in the sky and is only 8.6 light years away, it is the closest star visible to the naked eye after the Sun. Sirius along with Betelgeuse and Procyon (α CMi) in Canis Minor, form an asterism known as the Winter Triangle. Directly above Orion and the Winter Triangle are the constellations of Gemini (The Twins), with the two bright stars of Castor and Pollux marking their heads and Auriga the charioteer, with its bright alpha star Capella (α Aur). Auriga is host to M36, M37 and M38 which are globular clusters and easily seen through binoculars or small telescope and Gemini plays host to M35. Only a few of the objects available to see have been mentioned, so get yourself a good map, Planisphere or star atlas and see what other objects you can track down!

In the last two weeks, satellites Jason-1 and Galaxy Evolution Explorer (Galex), flying at different altitudes in low-Earth Orbit (LEO), died without the appropriate end-of-life measures intended to prevent the creation of new space debris. The Jason-1 U.S.-French ocean-altimetry satellite, orbiting at about 1300 km with an inclination of 66°, lost contact with ground stations on June 21. Although all its instruments were healthy before the loss, the flight controllers were not able to reestablish downlink communications. Therefore, it was decided to decommission the spacecraft, by turning off its magnetometer and reaction wheels, and leaving the stricken satellite to orbit without control, on July 1. Jason-1 was launched in 2001 and greatly improved our knowledge on global climate change by measuring the level of the oceans. Although it was designed to last from three to five years, it survived for 11.5 years. In spring 2012, following some concerns about the aging of the control systems, the spacecraft was moved into a “graveyard orbit”. Its extra fuel was depleted and the satellite was reconfigured to make observations of Earth’s gravity field over the ocean. Jason-1 will not reenter Earth’s atmosphere for at least 1000 years. However, the spacecraft does not represent a hazard to the LEO environment, because the graveyard orbit is not highly populated by satellites or debris. More concerns should be raised with the situation of NASA’s Galex. Galex was an orbiting space telescope designed to observe the universe in ultraviolet wavelengths, with the goal of investigating the history of star formation. Launched in 2003, its mission was extended three times over a period of 10 years. Galex was shut down on June 28 without any maneuver to decrease its orbit. Therefore, the spacecraft will remain in orbit at least for 65 years, before falling to Earth and burning up upon re-entry. Before the decommissioning, Galex was orbiting in a near-circular orbit at 697 km with an inclination of 29°. Several studies in the past years have been estimated that the most critical orbits, where the chance of collision with other space objects is higher, are located between 600 and 1000 km. At these altitudes, dead spacecraft keep on orbiting around Earth for many years, since the drag effect is almost null. Currently, mitigation guidelines of the Inter Agency Space Debris Coordination Committee, adopted by UN in 2007, recommend that satellites in LEO should burn into the Earth’s atmosphere within 25 years from the end of operations, to prevent them from increasing the number of existing debris. Therefore, satellite operators should act appropriately to fulfill the requirements, normally by including enough fuel for deorbit. However, as highlighted by Envisat’s loss, satellite operators tend to capitalize on expensive spacecraft long after the planned mission lifetime, by “pushing their luck” until something goes inevitably wrong. Meanwhile, far from the Earth’s orbit, another spacecraft, the Kepler space observatory is fighting against the aging of its control systems. The 4.7-meter-long satellite has been in safe mode since mid-May, when it lost the second of four reaction wheels needed to maintain the accurate pointing of the spacecraft. “The engineering team has devised initial tests for the recovery attempt and is checking them on the spacecraft test bed at the Ball Aerospace facility in Boulder, Colorado,” said Roger Hunter, Kepler project manager in an update issued on July 3. “The team anticipates that exploratory commanding of Kepler’s reaction wheels will commence mid- to late July.” While Kepler’s fate remains unknown, the CNES’s Convection, Rotation and Planetary Transits satellite (CoRoT) was officially shut down in late June. CoRoT suffered a computer failure in November 2012 and the French space agency was not able to retrieve data from the telescope. After many efforts to restore the on-board computer, CNES decide to retire its exoplanet hunting mission.

As the morning star, the evening star, and the brightest natural object in the sky (after the Moon), human beings have been aware of Venus since time immemorial. Even though it would be many thousands of years before it was recognized as being a planet, its has been a part of human culture since the beginning of recorded history. Because of this, the planet has played a vital role in the mythology and astrological systems of countless peoples. With the dawn of the modern age, interest in Venus has grown, and observations made about its position in the sky, changes in appearance, and similar characteristics to Earth have taught us much about our Solar System. Size, Mass, and Orbit: Because of its similar size, mass, proximity to the Sun, and composition, Venus is often referred to as Earth’s “sister planet”. With a mass of 4.8676×1024 kg, a surface area of 4.60 x 108 km², and a volume of 9.28×1011 km3, Venus is 81.5% as massive as Earth, and has 90% of its surface area and 86.6% of its volume. Venus orbits the Sun at an average distance of about 0.72 AU (108,000,000 km/67,000,000 mi) with almost no eccentricity. In fact, with its farthest orbit (aphelion) of 0.728 AU (108,939,000 km) and closest orbit (perihelion) of 0.718 AU (107,477,000 km), it has the most circular orbit of any planet in the Solar System. When Venus lies between Earth and the Sun, a position known as inferior conjunction, it makes the closest approach to Earth of any planet, at an average distance of 41 million km (making it the closest planet to Earth). This takes place, on average, once every 584 days. The planet completes an orbit around the Sun every 224.65 days, meaning that a year on Venus is 61.5% as long as a year on Earth. Unlike most other planets in the Solar System, which rotate on their axes in an counter-clockwise direction, Venus rotates clockwise (called “retrograde” rotation). It also rotates very slowly, taking 243 Earth days to complete a single rotation. This is not only the slowest rotation period of any planet, it also means that a sidereal day on Venus lasts longer than a Venusian year. Composition and Surface Features: Little direct information is available on the internal structure of Venus. However, based on its similarities in mass and density to Earth, scientists believe that they share a similar internal structure – a core, mantle, and crust. Like that of Earth, the Venusian core is believed to be at least be partially liquid because the two planets have been cooling at about the same rate. One difference between the two planets is the lack of evidence for plate tectonics, which could be due to its crust being too strong to subduct without water to make it less viscous. This results in reduced heat loss from the planet, preventing it from cooling and the possibility that internal heat is lost in periodic major resurfacing events. This is also suggested as a possible reason for why Venus has no internally generated magnetic field. Venus’ surface appears to have been shaped by extensive volcanic activity. Venus also has several times as many volcanoes as Earth, and has 167 large volcanoes that are over 100 km across. The presence of these volcanoes is due to the lack of plate tectonics, which results in an older, more preserved crust. Whereas Earth’s oceanic crust is subject to subduction at its plate boundaries, and is on average ~100 million years old, the Venusian surface is estimated to be 300-600 million years of age. There are indications that volcanic activity may be ongoing on Venus. Missions performed by the Soviet space program in 1970s and more recently by the European Space Agency have detected lightning storms in Venus’ atmosphere. Since Venus does not experience rainfall (except in the form of sulfuric acid), it has been theorized that the lightning is being caused by a volcanic eruption. Other evidence is the periodic rise and fall of sulfur dioxide concentrations in the atmosphere, which could be the result of periodic, large volcanic eruptions. And finally, localized infrared hot spots (likely to be in the range of 800 – 1100 K) have appeared on the surface, which could represent lava freshly released by volcanic eruptions. The preservation of Venus’ surface is also responsible for its impact craters, which are impeccably preserved. Almost a thousand craters exist, which are evenly distributed across the surface and range from 3 km to 280 km in diameter. No craters smaller than 3 km exist because of the effect the dense atmosphere has on incoming objects. Essentially, objects with less than a certain amount of kinetic energy are slowed down so much by the atmosphere that they do not create an impact crater. And incoming projectiles less than 50 meters in diameter will fragment and burn up in the atmosphere before reaching the ground. Atmosphere and Climate: Surface observations of Venus have been difficult in the past, due to its extremely dense atmosphere, which is composed primarily of carbon dioxide with a small amount of nitrogen. At 92 bar (9.2 MPa), the atmospheric mass is 93 times that of Earth’s atmosphere and the pressure at the planet’s surface is about 92 times that at Earth’s surface. Venus is also the hottest planet in our Solar System, with a mean surface temperature of 735 K (462 °C/863.6 °F). This is due to the CO²-rich atmosphere which, along with thick clouds of sulfur dioxide, generates the strongest greenhouse effect in the Solar System. Above the dense CO² layer, thick clouds consisting mainly of sulfur dioxide and sulfuric acid droplets scatter about 90% of the sunlight back into space. The surface of Venus is effectively isothermal, which means that their is virtually no variation in Venus’ surface temperature between day and night, or the equator and the poles. The planet’s minute axial tilt – less than 3° compared to Earth’s 23° – also minimizes seasonal temperature variation. The only appreciable variation in temperature occurs with altitude. The highest point on Venus, Maxwell Montes, is therefore the coolest point on the planet, with a temperature of about 655 K (380 °C) and an atmospheric pressure of about 4.5 MPa (45 bar). Another common phenomena is Venus’ strong winds, which reach speeds of up to 85 m/s (300 km/h; 186.4 mph) at the cloud tops and circle the planet every four to five Earth days. At this speed, these winds move up to 60 times the speed of the planet’s rotation, whereas Earth’s fastest winds are only 10-20% of the planet’s rotational speed. Venus flybys have also indicated that its dense clouds are capable of producing lightning, much like the clouds on Earth. Their intermittent appearance indicates a pattern associated with weather activity, and the lightning rate is at least half of that on Earth. Although ancients peoples knew about Venus, some of the cultures thought it was two separate celestial objects – the evening star and the morning star. Although the Babylonians realized that these two “stars” were in fact the same object – as indicated in the Venus tablet of Ammisaduqa, dated 1581 BCE – it was not until the 6th century BCE that this became a common scientific understanding. Many cultures have identified the planet with their respective goddess of love and beauty. Venus is the Roman name for the goddess of love, while the Babylonians named it Ishtar and the Greeks called it Aphrodite. The Romans also designated the morning aspect of Venus Lucifer (literally “Light-Bringer”) and the evening aspect as Vesper (“evening”, “supper”, “west”), both of which were literal translations of the respective Greek names (Phosphorus and Hesperus). The transit of Venus in front of the Sun was first observed in 1032 by the Persian astronomer Avicenna, who concluded that Venus is closer to Earth than the Sun. In the 12th century, the Andalusian astronomer Ibn Bajjah observed two black spots in front of the sun, which were later identified as the transits of Venus and Mercury by Iranian astronomer Qotb al-Din Shirazi in the 13th century. By the early 17th century, the transit of Venus was observed by English astronomer Jeremiah Horrocks on December 4th, 1639, from his home. William Crabtree, a fellow English astronomer and friend of Horrocks’, observed the transit at the same time, also from his home. When the Galileo Galilei first observed the planet in the early 17th century, he found it showed phases like the Moon, varying from crescent to gibbous to full, and vice versa. This behavior, which could only be possible if Venus’ orbited the Sun, became part of Galileo’s challenge to the Ptolemaic geocentric model and his advocacy of the Copernican heliocentric model. The atmosphere of Venus was discovered in 1761 by Russian polymath Mikhail Lomonosov, and then observed in 1790 by German astronomer Johann Schröter. Schröter found when the planet was a thin crescent, the cusps extended through more than 180°. He correctly surmised this was due to the scattering of sunlight in a dense atmosphere. In December 1866, American astronomer Chester Smith Lyman made observations of Venus from the Yale Observatory, where he was on the board of managers. While observing the planet, he spotted a complete ring of light around the dark side of the planet when it was at inferior conjunction, providing further evidence for an atmosphere. Little else was discovered about Venus until the 20th century, when the development of spectroscopic, radar, and ultraviolet observations made it possible to scan the surface. The first UV observations were carried out in the 1920s, when Frank E. Ross found that UV photographs revealed considerable detail, which appeared to be the result of a dense, yellow lower atmosphere with high cirrus clouds above it. Spectroscopic observations in the early 20th century also gave the first clues about the Venusian rotation. Vesto Slipher tried to measure the Doppler shift of light from Venus. After finding that he could not detect any rotation, he surmised the planet must have a very long rotation period. Later work in the 1950s showed the rotation was retrograde. Radar observations of Venus were first carried out in the 1960s, and provided the first measurements of the rotation period, which were close to the modern value. Radar observations in the 1970s, using the radio telescope at the Arecibo Observatory in Puerto Rico revealed details of the Venusian surface for the first time – such as the presence of the Maxwell Montes mountains. Exploration of Venus: The first attempts to explore Venus were mounted by the Soviets in the 1960s through the Venera Program. The first spacecraft, Venera-1 (also known in the west as Sputnik-8) was launched on February 12th, 1961. However, contact was lost seven days into the mission when the probe was about 2 million km from Earth. By mid-may, it was estimated that the probe had passed within 100,000 km (62,000 miles) of Venus. The United States launched the Mariner 1 probe on July 22nd, 1962, with the intent of conducting a Venus flyby; but here too, contact was lost during launch. The Mariner 2 mission, which launched on December 14th, 1962, became the first successful interplanetary mission and passed within 34,833 km (21,644 mi) of Venus’ surface. Its observations confirmed earlier ground-based observations which indicated that though the cloud tops were cool, the surface was extremely hot – at least 425 °C (797 °F). This put an end all speculation that the planet might harbor life. Mariner 2 also obtained improved estimates of Venus’s mass, but was unable to detect either a magnetic field or radiation belts. The Venera-3 spacecraft was the Soviets second attempt to reach Venus, and their first attempted to place a lander on the planet’s surface. The spacecraft cash-landed on Venus on March 1st, 1966, and was the first man-made object to enter the atmosphere and strike the surface of another planet. Unfortunately, its communication system failed before it was able to return any planetary data. On October 18th, 1967, the Soviets tried again with the Venera-4 spacecraft. After reaching the planet, the probe successfully entered the atmosphere and began studying the atmosphere. In addition to noting the prevalence of carbon dioxide (90-95%), it measured temperatures in excess of what Mariner 2 observed, reaching almost 500 °C. Due to the thickness of Venus’ atmosphere, the probe descended slower than anticipated, and its batteries ran out after 93 minutes when the probe was still 24.96 km from the surface. One day later, on October 19th, 1967, Mariner 5 conducted a fly-by at a distance of less than 4000 km above the cloud tops. Originally built as a backup for the Mars-bound Mariner 4, the probe was refitted for a Venus mission after Venera-4‘s success. The probe managed to collect information on the composition, pressure and density of the Venusian atmosphere, which was then analyzed alongside the Venera-4 data by a Soviet-American science team during a series of symposiums. Venera-5 and Venera-6 were launched in January of 1969, and reached Venus on 16th and 17th of May. Taking into account the extreme density and pressure of Venus’ atmosphere, these probes were able to achieve a faster descent and reached an altitude of 20 km before being crushed – but not before returning over 50 minutes of atmospheric data. The Venera-7 was built with the intent of returning data from the planet’s surface, and was construed with a reinforced descent module capable of withstanding intense pressure. While entering the atmosphere on December 15th, 1970, the probe crashed on the surface, apparently due to a ripped parachute. Luckily, it managed to return 23 minutes of temperature data and the first telemetry from the another planet’s surface before going offline. The Soviets launched three more Venera probes between 1972 and 1975. The first landed on Venus on July 22nd, 1972, and managed to transmit data for 50 minutes. Venera-9 and 10 – which entered Venus’ atmosphere on October 22nd and October 25th, 1975, respectively – both managed to send back images of Venus’ surface, the first images ever taken of another planet’s landscape. On November 3rd, 1973, the United States had sent the Mariner 10 probe on a gravitational slingshot trajectory past Venus on its way to Mercury. By February 5th, 1974, the probe passed within 5790 km of Venus, returning over 4000 photographs. The images, which were the best to date, showed the planet to be almost featureless in visible light; but revealed never-before-seen details about the clouds in ultraviolet light. By the late seventies, NASA commenced the Pioneer Venus Project, which consisted of two separate missions. The first was the Pioneer Venus Orbiter, which inserted into an elliptical orbit around Venus on December 4th, 1978, where it studied its atmosphere and mapped the surface for a period of 13 days. The second, the Pioneer Venus Multiprobe, released a total of four probes which entered the atmosphere on December 9th, 1978, returning data on its composition, winds and heat fluxes. Four more Venera lander missions took place between the late 70s and early 80s. Venera 11 and Venera 12 detected Venusian electrical storms; and Venera 13 and Venera 14 landed on the planet on March 1st and 5th, 1982, returning the first color photographs of the surface. The Venera program came to a close in October 1983, when Venera 15 and Venera 16 were placed in orbit to conduct mapping of the Venusian terrain with synthetic aperture radar. In 1985, the Soviets participated in a collaborative venture with several European states to launch the Vega Program. This two-spacecraft initiative was intended to take advantage of the appearance of Halley’s Comet in the inner Solar System, and combine a mission to it with a flyby of Venus. While en route to Halley on June 11th and 15th, the two Vega spacecraft dropped Venera-style probes supported by balloons into the upper atmosphere – which discovered that it was more turbulent than previously estimated, and subject to high winds and powerful convection cells. NASA’s Magellan spacecraft was launched on May 4th, 1989, with a mission to map the surface of Venus with radar. In the course of its four and a half year mission, Magellan provided the most high-resolution images to date of the planet and was able to map 98% of the surface and 95% of its gravity field. In 1994, at the end of its mission, Magellan was sent to its destruction into the atmosphere of Venus to quantify its density. Venus was observed by the Galileo and Cassini spacecraft during flybys on their respective missions to the outer planets, but Magellan was the last dedicated mission to Venus for over a decade. It was not until October of 2006 and June of 2007 that the MESSENGER probe would conduct a flyby of Venus (and collect data) in order to slow its trajectory for an eventual orbital insertion of Mercury. The Venus Express, a probe designed and built by the European Space Agency, successfully assumed polar orbit around Venus on April 11th, 2006. This probe conducted a detailed study of the Venusian atmosphere and clouds, and discovered an ozone layer and a swirling double-vortex at the south pole before concluding its mission in December of 2014. The Japan Aerospace Exploration Agency (JAXA) devised a Venus orbiter – Akatsuki (formerly “Planet-C”) – to conduct surface imaging with an infrared camera, studies on Venus’ lightning, and to determine the existence of current volcanism. The craft was launched on May 20th, 2010, but the craft failed to enter orbit in December 2010. Its main engine is still offline, but its controllers will attempt to use its small attitude control thrusters to make another orbital insertion attempt on December 7th, 2015. In late 2013, NASA launched the Venus Spectral Rocket Experiment, a sub-orbital space telescope. This experimented is intended to conduct ultraviolet light studies of Venus’s atmosphere, for the purpose of learning more about the history of water on Venus. The European Space Agency’s (ESA) BepiColombo mission, which will launch in January 2017, will perform two flybys of Venus before it reaches Mercury orbit in 2020. NASA will launch the Solar Probe Plus in 2018, which will perform seven Venus flybys during its six-year mission to study the Sun. Under its New Frontiers Program, NASA has proposed mounting a lander mission to Venus called the Venus In-Situ Explorer by 2022. The purpose will be to study Venus’ surface conditions and investigate the elemental and mineralogical features of the regolith. The probe would be equipped with a core sampler to drill into the surface and study pristine rock samples not weathered by the harsh surface conditions. The Venera-D spacecraft is a proposed Russian space probe to Venus, which is scheduled to be launched around 2024. This mission will conduct remote-sensing observations around the planet and deploy a lander, based on the Venera design, capable of surviving for a long duration on the surface. Because of its proximity to Earth, and its similarity in size, mass and composition, Venus was once believed to hold life. In fact, the idea of Venus being a tropical world persisted well into the 20th century, until the Venera and Mariner programs demonstrated the absolute hellish conditions that actually exist on the planet. Nevertheless, it is believed that Venus may once have been much like Earth, with a similar atmosphere and warm, flowing water on its surface. This notion is supported by the fact that Venus sits within the inner edge of the Sun’s habitable zone and has an ozone layer. However, owing to the runaway greenhouse effect and the lack of a magnetic field, this water disappeared many billions of years ago. Still, there are those who believed that Venus could one day support human colonies. Currently, the atmospheric pressure near to the ground is far too extreme for settlements to be built on the surface. But 50 km above the surface, both the temperature and air pressure are similar to Earth’s, and both nitrogen and oxygen are believed to exist. This has led to proposals for “floating cities” to be built in the Venusian atmosphere and the exploration of the atmosphere using Airships. In addition, proposals have been made suggesting the Venus should be terraformed. These have ranged from installing a huge space-shade to combat the greenhouse effect, to crashing comets into the surface to blow the atmosphere off. Other ideas involve converting the atmosphere using calcium and magnesium to sequester the carbon away. Much like proposals to terraform Mars, these ideas are all in their infancy and are hard-pressed to address the long-term challenges associated with changing the planet’s climate. However, they do show that humanity’s fascination with Venus has not diminished over time. From being a central to our mythology and the first star we saw in the morning (and the last one we saw at night), Venus has since gone on to become a subject of fascination for astronomers and a possible prospect for off-world real estate. But until such time as technology improves, Venus will remain Earth’s hostile and inhospitable “sister planet”, with intense pressure, sulfuric acid rains, and a toxic atmosphere. We have written many interesting articles about Venus here at Universe Today. For example, here’s The Planet Venus, Interesting Facts About Venus, What is the Average Temperature of Venus?, How Do We Terraform Venus? and Colonizing Venus With Floating Cities.

Neptune’s smallest moon no longer has to go by its previous names of “Neptune XIV” and “S/2004 N1” as it’s now officially known as “Hippocamp”. A team that was led by Mark Showalter of the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California, confirmed the existence of the small moon back in 2013 after studying photographs that were captured by NASA’s Hubble Space Telescope from 2004 to 2009. Studies showed that the moon is located approximately 65,400 miles from Neptune and it takes around 23 hours to complete one full orbit. To better understand the proximity of Hippocamp to Neptune, our own moon orbits Earth at a distance averaging 239,000 miles. Out of Neptune’s 14 known moons, Hippocamp is the smallest, as it was thought to have a diameter of no more than 12 miles. However, a new study suggests that it may be slightly larger with a diameter of around 21 miles. That would make it around the same size as the distant object, Ultima Thule. It’s hard to imagine a moon that tiny, as our own moon measures 2,160 miles wide. As for its name, Hippocamp is a fish-tailed, horse-headed creature in Greek mythology, adding to the Greco-Roman mythology and the sea for the names of the Neptune system. In addition, the name Neptune means the Roman God of the sea which is comparable to the Greek Poseidon. It’s incredible how the researchers found the small moon in the first place. They took eight five-minute Hubble exposures in sequence of the Neptune system and then they readjusted the pixels in order to stack the photographs on top of each other and that’s how they discovered the tiny moon. “We came really close to missing it entirely,” Showalter said, “It’s too faint to see in a single Hubble [exposure].” The team also used transformation-stacking to locate another one of Neptune’s moons called Naiad which hadn’t been seen since 1989. Hippocamp is located in the same area as the six moons that were discovered by NASA’s Voyager 2 spacecraft in 1989 and it’s only 7,450 miles interior to Proteus which is the outermost and biggest of the six moons, measuring at 260 miles wide. It is thought that Hippocamp was more than likely located next to Proteus around 4 billion years ago. In fact, Showalter and his colleagues believe that Hippocamp is younger than Proteus and that perhaps it was created from pieces that were sent into space after the larger moon collided with a comet. It could even be connected to the Pharos Crater that’s located on Proteus from a once huge impact. “This is the first really great example of a moon that got created as a result of an impact,” Showalter suggested.

Although dark matter is inherently difficult to observe, an understanding of its properties (even if not its nature) allows astronomers to predict where its effects should be felt. The current understanding is that dark matter helped form the first galaxies by providing gravitational scaffolding in the early universe. These galaxies were small and collapsed to form the larger galaxies we see today. As galaxies grew large enough to shred incoming satellites and their dark matter, much of the dark matter should have been deposited in a flat structure in spiral galaxies which would allow such galaxies to form dark components similar to the disk and halo. However, a new study aimed at detecting the Milky Way’s dark disk have come up empty. The study concentrated on detecting the dark matter by studying the luminous matter embedded in it in much the same way dark matter was originally discovered. By studying the kinematics of the matter, it would allow astronomers to determine the overall mass present that would dictate the movement. That observed mass could then be compared to the amount of mass predicted of both baryonic matter as well as the dark matter component. The team, led by C. Moni Bidin used ~300 red giant stars in the Milky Way’s thick disk to map the mass distribution of the region. To eliminate any contamination from the thin disc component, the team limited their selections to stars over 2 kiloparsecs from the galactic midplane and velocities characteristic of such stars to avoid contamination from halo stars. Once stars were selected, the team analyzed the overall velocity of the stars as a function of distance from the galactic center which would give an understanding of the mass interior to their orbits. Using estimations on the mass from the visible stars and the interstellar medium, the team compared this visible mass to the solution for mass from the observations of the kinematics to search for a discrepancy indicative of dark matter. When the comparison was made, the team discovered that, “[t]he agreement between the visible mass and our dynamical solution is striking, and there is no need to invoke any dark component.” While this finding doesn’t rule out the presence of dark matter, it does place constraints on it distribution and, if confirmed in other galaxies, may challenge the understanding of how dark matter serves to form galaxies. If dark matter is still present, this study has demonstrated that it is more diffuse than previously recognized or perhaps the disc component is flatter than previously expected and limited to the thin disc. Further observations and modeling will undoubtedly be necessary. Yet while the research may show a lack of our understanding of dark matter, the team also notes that it is even more devastating for dark matter’s largest rival. While dark matter may yet hide within the error bars in this study, the findings directly contradict the predictions of Modified Newtonian Dynamics (MOND). This hypothesis predicts the apparent gain of mass due to a scaling effect on gravity itself and would have required that the supposed mass at the scales observed be 60% higher than indicated by this study.

This photo of a galaxy in the constellation of Hercules was produced from combining an optical image from the Hubble Space...Read More >>This photo of a galaxy in the constellation of Hercules was produced from combining an optical image from the Hubble Space telescope and a radio image from the Very Large Array (VLA) telescope in New Mexico, USA. The VLA radio telescope reveals two spectacular pink jets of energetic particles blasting out of a black hole at the centre of the Hercules galaxy (the yellowish cloud) that would be otherwise invisible. Objects in space, such as stars and galaxies, do not just give off light. They also give off radiation from other parts of the electromagnetic spectrum, such as infrared radiation, radio waves, X-rays and ultraviolet radiation. There are some objects in space that only give off these kinds of radiation and that are otherwise invisible. They cannot be seen with ordinary optical telescopes, so special telescopes, called radio telescopes, are needed. The Arecibo radio telescope in Puerto Rico. The dish is built into a natural bowl in the landscape. It focuses radio waves from...Read More >>The Arecibo radio telescope in Puerto Rico. The dish is built into a natural bowl in the landscape. It focuses radio waves from the sky on the dome suspended above it on cables. The telescope is used in the search for extraterrestrial life. A signal intended for possible aliens, called the Arecibo message, was transmitted towards a cluster of stars about 25,000 light-years away in 1974. Radio telescopes look like giant satellite dishes. The dish acts as a reflector, collecting radio waves and focusing them on to a detector, where an image is formed. They can be turned to face any part of the sky. They are also used in the search for alien life in the Universe. Radio astronomy has led to the discovery of new celestial objects such as pulsars, rapidly spinning neutron stars. The largest radio telescope is the RATAN-600 array near Nizhny Arkhyz, Russia. It consists of a 576 m (1890 ft) circle of dishes. The second largest is the Five-hundred-metre Aperture Spherical radio Telescope (FAST) in Guizhou, which began operations in September 2016. Find the answer

The news that astronomers have confirmed the presence of a planet around a nearby star is exciting, sure, but don’t expect an interstellar probe to be launched any time soon. At 10.5 light-years away, the star, Epsilon Eridani, is just around the corner, celestially speaking. But that’s still 6,774 times farther than Voyager 1, our most remote spacecraft, has managed to travel in 29 years, zipping along at a million miles a day. From This Story You see the problem. The fundamental challenge of time and distance has inspired many suggestions for interstellar flight, from multi-generation arks to beam-propelled star-sails. The latter, though undeniably elegant, would bankrupt whole nations just to produce the energy for the beam—if they had a beam. Still, hope springs eternal, and future-minded scientists and engineers continue to pick at the problem, hoping to find some shortcut or trick to make star travel possible. The latest is Mason Peck, an assistant professor of mechanical and aerospace engineering at Cornell University in New York whose pre-academic career involved more conventional aerospace work at Bell Helicopter, Hughes, and Boeing. Peck wants to use natural forces to propel starships no bigger than the integrated-circuit chips in your computer. Specifically, he would harness the Lorentz forces that drive charged particles in magnetic fields, and which physicists use to whip bits of atoms to hellacious speeds in giant particle accelerators on Earth. Jupiter, with a rapidly rotating magnetic field 20,000 times stronger than Earth’s, packs a powerful Lorentz punch. A pulsar would be even better. Spacecraft like Voyager and Cassini routinely use gravity boosts from large planets to gain acceleration; why not use Lorentz forces as a means of propulsion too? Boosts from rotating magnetic fields could theoretically accelerate spacecraft to speeds of 1 to 10 percent of the speed of light, according to Peck’s early calculations. Because this free energy source works best on small objects, he suggests building a really tiny starship. Extrapolating from today’s state-of-the-art, he assumes we can solve the practical problems of nano-fabricating a spacecraft-on-a-chip, a single semiconductor crystal only a centimeter square and weighing less than a gram. One side would consist of solar cells for power. A rudimentary radio antenna and digital camera would be etched or deposited on the other. Attitude could be controlled by spinning the spacecraft and by torquing against the magnetic field, a technique already used for Earth-orbiting satellites. Tied to the star-chip would be a kilometer-long, micron-thin filament that would hold enough electrostatic charge to provide the Lorentz propulsion. Since there isn’t much power or capability in a single chip, Peck envisions billions of them thousands of miles apart, forming a long communications bridge to a nearby star. Any communication would have to be simple—sending the sequence of human DNA encoded in the microcircuits, perhaps, or returning a few precious close-up pictures of a distant planet. Peck has a grant from NASA’s Institute for Advanced Concepts, a kind of incubator for beyond-the-horizon thinking, to develop the idea further. He plans to use some of the money to study the feasibility of charging very small spacecraft in magnetic fields, and to supplement work already under way to build a simple spacecraft-on-a-chip at Cornell’s NanoScale Science and Technology Facility. If Lorentz propulsion is practical—it’s too early to know—it could have applications for spacecraft missions within our own solar system. Better yet, it could take us to nearby stars like Epsilon Eridani with no big leaps in technology, and do it "within a lifetime or two," says Peck. That way we won’t lose interest while the probe is en route. "Humans won’t have yet evolved into some other species that doesn’t care that it actually happened," he jokes.

The Boiler Room Gliese 876 d Discovered by: Eugenio Rivera, et al. Distance from Earth: ~15 light-years Mass: ~6.9 Earth masses (~0.02 Jupiter masses) Surface climate: A mystery Habitability for humans: No. For this week’s exoplanet, we’re looking at another planet that’s virtually the Solar System’s upstairs neighbor. Gliese 876 d is the innermost of four known planets orbiting a red dwarf just fifteen light-years away. It’s a curious system, not least because the timing of the other three planets’ orbits falls neatly into a 1:2:4 pattern — similar to Io, Europa, and Ganymede around Jupiter. It’s where some scientists think ‘Oumuamua, the mysterious cylindrical object that recently tumbled through the Solar System from interstellar space, may have come from. When Gliese 876 d was found in 2005, it had the lowest mass of any known exoplanet around a main sequence star. Its discovery sparked a candle of interest in one of the first “super-Earth.” Although it’s still heavier than Earth by several times over, in a year when virtually all known exoplanets were superhot gas giants, a planet that could have been terrestrial was groundbreaking — with some even whispering it might be habitable for Earth-like life. But even if Gliese 876 d is terrestrial, being habitable — at least for Earth life — isn’t quite in the question. The planet is far too close, orbiting at only 0.02 AU, a fraction of Mercury’s distance from the Sun. Even though its star is much smaller and cooler than the Sun, Gliese still basks in 600-degree heat. Furthermore, Gliese 876 d would be at the mercy for its star’s gravity, tidal forces literally tearing the planet’s interior apart. Artists dreaming what the planet might look like often depict a surface latticed and pockmarked with the molten pools and glowing lines of volcanic activity. But another theory suggests that Gliese 876 d isn’t quite terrestrial — but actually that Gliese 876 d is actually the remnant inner layers of a gas giant, cast away into the depths of its inner solar system, its outer layers left to be blown away by its sun. What that would mean is a “super-Earth” that’s far different to our inner Solar System, and a planet that’s far weirder than anyone could have imagined when Gliese 876 d was first discovered. That planet might be resplendent with bizarre oddities — things that are all thought to exist on gas giants in our Solar System, but pop out to the surface on a world like this. Scientists think that, in his scenario, Gliese 876 d could be covered by a superhot, supercritical ocean of water — high pressures keeping that water liquid even in the high temperatures. Its star’s radiation would break down that water into an atmosphere of water vapor and oxygen. Underneath the supercritical water, the pressures would only intensify, crystallizing that ocean into a bizarre form of ice. Even if that’s not the case, it’s still possible, and there’s far more planets in existence than just what we can see in our Solar System.

Study investigates potential risk of Taurid meteor swarm A new study from Western University posits proof to the possibility that an oncoming swarm of meteors—likened to the Loch Ness Monster and Bigfoot by some extraterrestrial experts—may indeed pose an existential risk for Earth and its inhabitants. (That's us.) When considering catalysts for catastrophic collision, there are two main sources Near Earth Objects (NEOs) like asteroids and meteoroids and interlopers from the outer solar system, which are typically comets. Over the past few decades, a great deal of effort has been expended in cataloging more than 90 percent of the potentially hazardous NEOs, and work is ongoing to detect, catalog and track greater numbers and smaller sizes of these objects. Interlopers from the outer solar system are much harder to chart but again, much work is underway. The Taurid swarm is a third potential source of risk that changes the probabilities of possible catastrophic impacts. The Tunguska (Russia) explosion of 1908 is considered a one-in-1000-year event, assuming a random distribution of events over time. But the Taurid swarm, a dense cluster within the Taurid meteoroid stream, and through which the Earth periodically passes, changes the odds significantly and gives a possible reason for the unlikely occurrence that a once per 1000-year event occurred just over a century ago. If the hypothesized might of the Taurid swarm is successfully proven, this also heightens the possibility of a cluster of large impacts over a short period of time. For the study, published by arXiv and accepted for publication in Monthly Notices of the Royal Astronomical Society, David Clark from Western's Department of Earth Sciences, and Paul Wiegert and Peter Brown from Western's Department of Physics & Astronomy simulated a large collection of 100-meter diameter meteoroids (like the one that triggered the 1908 Tunguska event) with orbits similar to the Taurid swarm and calculated their positions forward for 1,000 years. By analyzing, each object's position and motion over time, the astronomers calculated two optimal viewing times and telescope pointing locations for the Taurid swarm to properly investigate its overall risk potential. According to Western Meteor Physics Group data analysis, the Earth will approach within 30,000,000 km of the center of the Taurid swarm this summer, the closest such encounter since 1975. The calculations also show that this will be the best viewing time of the Taurid swarm until the early 2030s. "There has been great interest in the space community since we shared our results at the recent Planetary Defense Conference in Washington, DC," says David Clark, a Western graduate student and first author of the study. "There is strong meteoric and NEO evidence supporting the Taurid swarm and its potential existential risks but this summer brings a unique opportunity to observe and quantify these objects."

Are we alone in the universe? It’s one of the biggest questions that haunts our imaginations. Astrobiologist Adam Frank argues in his new book Light of the Stars that we have never been in a better position to answer that question, thanks to a revolution in our knowledge gained by powerful telescopes like Hubble and space probes like Voyager. Indeed, the chances that there has never been another civilization in the universe are as low as one in ten billion trillion. But whether there is still one out there today is a more complicated question. Speaking from his home in Rochester, New York, Frank explains how, after being rejected because of its New Age connotations, the Gaia Hypothesis has gained acceptance in the scientific community; how climate change is an inevitable feature of civilization building; and why we need to grow up as a civilization if we are to survive climate change. Your book centers on a relatively new field of study known as astrobiology, which you call revolutionary. Explain what it means and why it is giving us new insights into our place in the universe. Astrobiology is the study of life in its planetary or astronomical context. People will say we have only one example of life—here on Earth. But, if you take that position, you miss three revolutions that have happened in the last 30 years. PHOTOGRAPH COURTESY W.W. NORTON & COMPANY The first revolution is that we have been visiting other planets in our solar system. We have now sent probes to pretty much every kind of object in our solar system, including Mars. And from this we’ve learned about climate and how planets work in a generic sense. There’s an app you can pull up that will give you the weather on Mars. We have climate models for Mars, Venus, and Saturn, and we know a huge amount about climate as a generic planetary phenomenon, not just on Earth. The second revolution is studying the Earth’s history going back 4.5 billion years. We have been able to unspool in some detail the long history of the Earth and its life co-evolving over that time. We see that Earth has been many different kinds of planets, sometimes a snowball world, sometimes a hothouse world without ice. In the beginning there were no continents; it was pretty much a water world. The last big revolution is the exoplanet revolution. When I was a graduate student in 1985 I did not know whether there were any stars in the universe with planets around them. Now we know that the universe has ten billion trillion planets that are in the right place for life to form. Those three revolutions completely changed not only how we think about life and planets, but also leads us to think very differently about exo-civilizations. The big question we all want to know is are we alone? What’s your view, based on the evidence? In 2016, Woody Sullivan and I wrote a paper where we took all of the data from the exoplanet revolution and asked ourselves: What can we say with this data about exo-civilizations or aliens, as people like to call them? With science you have to tune the question to the data you have. And the question we could answer with that data was: How bad does the probability of forming a civilization on a random planet have to be for us to be alone, for us to be the only time in the entire history of the universe that there’s ever been a civilization? That number is 1 in 10 billion trillion. That number tells me that the only way that we can be the only civilization in cosmic history is if the odds are that low or lower. As long as there’s a probability larger than that, then it has happened before. So unless nature is really perversely biased against forming civilizations then there have been others. Whether there are others in existence today, I cannot answer. It all depends on this important factor in the Drake Equation, the average lifetime of a civilization. You could have planets creating civilizations all the time, but if nobody makes it to more than, say, 200 years, then right now we would be living in a sterile galaxy. We can say that, yes, there have probably overwhelmingly been civilizations before us. The next step is, does anybody last long, particularly when climate change is going to be a natural consequence of civilization-building? CLIMATE CHANGE 101 WITH BILL NYE Climate Change is a real and serious issue. In this video Bill Nye, the Science Guy, explains what causes climate change, how it affects our planet, why we need to act promptly to mitigate its effects, and how each of us can contribute to a solution. Carl Sagan said that we were “cosmic teenagers.” Explain that idea and how important Sagan is in our understanding of the cosmos. I grew up reading Carl Sagan’s books. He was enormously influential in my decision to become an astronomer and my decision to write about astronomy. But even I didn’t realize how deeply woven he was into every aspect of the story I was telling. The “cosmic teenager” idea is that we’re a very young species that’s just coming of age. What I argue is that climate change is our coming of age. I argue that there have been many civilizations before and, if you are a technological civilization like ours, you can’t help but trigger climate change. Every young civilization is going to trigger their version of the Anthropocene and that is what makes us cosmic teenagers. We have enough power over ourselves and the planet to change the planet, but it’s not yet clear that we have the wisdom to navigate the difficult transition through climate change. Venus offers a model for what is known as the greenhouse effect. Explain that idea, and what Venus can tell us about our own climate problems. In 1962, we sent the first probe to another planet, which happened to be Venus. There was already debate raging. People using telescopes had determined that Venus had this very high temperature, 700 degrees, which was way higher than expected because, even though it is closer to the sun than the Earth, it shouldn’t be that much hotter! The probe confirmed that, yes, those temperatures were real and it was Carl Sagan who realized that the reason Venus is so hot is that there is what we call a “runaway greenhouse effect.” There was so much CO2 in the atmosphere of Venus that the temperatures got high enough and it lost all its water. It was a feedback loop. CO2 built up in the atmosphere to the point where it acted like a blanket in the atmosphere—the sunlight that hits the surface warms it, and if there weren’t CO2 in the atmosphere, that warmth would just radiate back into space. This is starting to sound familiar…. Exactly! [laughs] The Venus greenhouse effect was so important because it was the first time we recognized that physical processes happening on Earth were universal. There are generic laws of planets, and once you learn those laws they are good for any planet, planets 10,000 light-years away, or for the Earth. That’s part of my story. We have to learn how to think like a planet now that we know the laws of planets, if we’re going to be able to make it through climate change. A key figure in these debates is James Lovelock. Tell us about the man and his vision of Gaia, and how, while not taken too seriously in the scientific community, he gained a huge following in popular culture. Lovelock is an interesting character because he’s been an independent scientist his whole life. He didn’t have an appointment at a university. He’s this mix of an inventor and a scientist, trained in chemistry, who also knew a lot of physics and created a device for measuring small concentrations of chemicals in the air that made him enough money that he could be semi-independent. In the early 1960s, the Jet Propulsion Laboratory invited him to work on experiments looking for life on Mars. The people at JPL thought they were going to go to Mars, dig up some earth and look for microbes. Lovelock said, “No, that’s the wrong way to do it! You should look at the atmosphere because, if there’s life, the atmosphere will be changed.” Lovelock builds on that idea over the years when he recognizes that not only has the atmosphere been changed by life, but that the atmosphere is being regulated by life—that the concentration of oxygen and other compounds are being kept exactly where they need to be to keep life healthy on the planet. At the same time Lovelock was thinking about this, the famous biologist Lynn Margulis was thinking about how microbes could regulate how the Earth behaved. She happened to be Carl Sagan’s first wife! [laughs] It was not a happy divorce, but they stayed in contact, and at some point in the early 1970s she contacted Sagan and said, “Hey, I’m working on this idea but I need a chemist, is there anybody you could recommend to me?” He introduces her to James Lovelock and together they put together the Gaia Theory. Lovelock wanted to call it something boring like Earth’s Systems Dynamics Theory. But his neighbor, William Golding, who wrote Lord of The Flies, said, “No! That’s a terrible name! You should name it after the Greek God of the Earth, Gaia.” It then became this hippie-dippy thing. People would have Gaia church services, Gaia music and Gaia new age priests. And this outpouring of whack-a-doodle support made many scientists queasy about the idea. Eventually, the name Gaia was dropped and people picked up the term Earth Systems Science. This recognized that there were a bunch of systems operating on the planet—the atmosphere, water, ice, rocks, and life—and that they were all strongly interdependent. Easter Island has haunted generations of scientists and writers as an example of a failed civilization. Give us a snapshot of the theories, and what this remote rock can tell us about our future. Easter Island is an island in the Pacific that’s a long way from anywhere. In that sense, it’s a perfect metaphor for a planet in space. Somewhere around 400 A.D. the island was colonized by Polynesian sailors, and probably started off with a few hundred individuals. But at the peak of the civilization there were probably 10,000-12,000 people on the island. It was a complex society, with the capacity to dig those giant rocks out from the central volcano and make those iconic statues. But after some time the population collapsed, so that when the Dutch found the island at Easter, in 1722, there were only about 2,000 people living meagre, subsistence lives. One of the dominant ideas—it’s complicated—is that that there was some form of ecocide, that people over-used the resources on the island and destroyed the environment. That is a metaphor for what we are doing on the Earth today. You write, “We urgently need to adapt civilization so that it can become fully and globally sustainable.” Map out the challenges facing us, especially from climate change, and how we can achieve that goal. What’s funny about this is that, on a certain level, it’s not hard at all. One of the messages I want people to understand is that the primary difficulty about making this change is in our head. Because, fundamentally, the step we need to take to create a sustainable future is change energy infrastructures. It’s really that simple! [laughs] The real problem is the way we look at the problems. We’re still stuck in this argument about whether or not climate change is even happening, certainly in the U.S. That comes from not having what I would call the astrobiological perspective. We don’t recognize ourselves as cosmic teenagers. If you’re 12 years old, you know adolescence is coming. But because we have the wrong view about ourselves and our place in the universe, we don’t see that, of course, climate change is coming! That inability to see the reality of what climate change means—its inevitability—keeps us from understanding the urgency and importance of acting on it. This interview was edited for length and clarity. Lead Image: A new book says that to go the distance all advanced civilizations—including any alien societies that have survived—have to solve climate change. PHOTOGRAPH BY BABAK TAFRESHI, NATIONAL GEOGRAPHIC CREATIVE

A wandering planet, that is a planet not in orbit around a star, was discovered by a team of researchers from the Université de Montréal and their European colleagues, using data from the Canada-France-Hawaii telescope (CFHT) and the VLT (Very Large Telescope) at the European Southern Observatory (ESO). “Although theorized, this type of planets, very young and cold, had never been observed to date, said Étienne Artigau, astrophysicist at UdeM. “ The absence of a bright star next to this planet star, allowed the team to study its atmosphere with a maximum of details. This research will allow astronomers to better understand exoplanets that are orbiting a star. Wandering planets are planets that have no gravitational link to a star. “In recent years, several objects of this type have been identified, but no valid estimate of their age could confirm their existence, explained Jonathan Gagné, a PhD student at UdeM. Therefore, astronomers were not able to classify them as planets or brown dwarfs. Brown dwarfs are what might be called “failed stars” because core nuclear reactions never trigger. “ Astrophysicists from the Center for Research in Astrophysics of Quebec (CRAQ) and the Département de physique at the Université de Montréal (Jonathan Gagné, Lison Malo, Stephen Artigau and Albert Loïc) managed to find this planet in collaboration with French astronomers, including Philippe Delorme of the Laboratoire d’astrophysique de Grenoble, principal investigator of the project. Going by the sweet name CFBDSIR2149, this planet seems to be part of a very young group of stars known as the AB Doradus association. “This group has the distinction of being composed of about thirty stars sharing the same age, the same chemical composition, and moving together in space. Establishing a link between the planet and AB Doradus allowed us to infer its age and classify it as a planet, “said PhD student Lison Malo. The team first obtained a series of infrared images of CFBDSIR2149 on the CFHT 3.6 m telescope, and then used data from the more powerful VLT 8 m telescope to deduce its mass, temperature and age. CFBDSIR2149 is between 50 and 120 million years old, it has a temperature of around 400 ° C and has a mass of 4 to 7 times the mass of Jupiter. Objects that are more than 13 times the mass of Jupiter are considered brown dwarf stars, because this is the minimum mass for deuterium fusion in the core of a star. This discovery gives credit to the original meaning of the word planet. “The etymology of the word planet comes from the Latin word planetus, itself derived from the Greek word planeta, or planets, which means moving stars or wandering stars, as opposed to stars that appear stationary in the sky “, said Olivier Hernandez, astrophysicist at UdeM. This is the 1st isolated planet (it could have been ejected during its formation), not gravitationally bound to a star, whose mass, temperature and age are all constrained. This result, sought for over 10 years, supports theories of stars and planets formation. It also argues in favor of theories claiming that the number of orphan objects of this type is much higher than we think. “This object was found during a survey that covered the equivalent of 1,000 times the size of the full moon, explained Étienne Artigau. We have been looking at hundreds of millions of stars and planets … and we only found one wandering planet close to us. These objects are not necessarily rare, but we see only those that are close to us and we must sift through an astronomical number of more distant sources. It’s like finding a single needle in a thousand haystacks. “ Other links discussing CFBDSIR2149’s discovery :

Caption: NASA: S74-15583 (July 1973) --- A huge solar eruption can be seen in this Spectroheliogram obtained during the Skylab 3 mission by the Extreme Ultraviolet Spectrograph/Spectroheliograph SO82A Experiment aboard the Skylab space station in Earth orbit. SO82 is one of the Apollo Telescope Mount experiments. The SO82 A instrument covers the wavelength region from 150-650 angstroms (EUV regions). The caption may have been written in the 1970's. Is there still a mystery about the forces, or are things somewhat better understood now? The only other (fundamental) force that could be relevant is electric, but I wonder if that was meant to be implicit (as electromagnetic). See statement highlighted in bold below, as the caption continues: The magnitude of the eruption can be visualized by comparing it with the small white dot that represents the size of Earth. This photograph reveals for the first time that helium erupting from the sun can stay together to altitudes of up to 500,000 miles. After being ejected from the sun, the gas clouds seem to have come to a standstill, as though blocked by an unseen wall. Some materials appear to have been directed back toward the sun as a rain, distinguished by fine threads. At present it is a challenge to explain this mystery--what forces expelled these huge clouds, then blocked its further progress, yet allowed the cloud to maintain its threads. Both magnetic fields and gravity must play a part, but these curious forms seem to defy explanation based on magnetic and gravitational fields alone. The EUV spectroheliograph was designed and constructed by the U.S. Naval Research Laboratory and the Ball Brothers Research Corporation under the direction of Dr. R. Tousey, the principal investigator for this NASA experiment. On the left may be seen the sun's image in emission from iron atoms which have lost 14 electrons by collision in the sun's million-degree coronal plasma gas. (emphasis added) If I understand correctily, this is a telescopic view with a diffraction grating in the optical path - the clear image and its "echoes" are the result of each strong, narrow emission line producing an image at a different angle of the grating's dispersion.

You are constantly accelerating. The Earth’s gravity is pulling you downward at g = 9.8 meters per second per second. It wants to take your velocity up to about 10 meters per second after only the first second of free fall. Normally you don’t fall, because the floor is solid due to electromagnetic forces and also it is electromagnetic forces that give your body structural integrity and power your muscles, resisting the pull of gravity. You are also accelerating due to the Earth’s spin and its revolution about the Sun. International Space Station, image credit: NASA Our understanding of gravity comes primarily from these large accelerations, such as the Earth’s pull on ourselves and on satellites, the revolution of the Moon about the Earth, and the planetary orbits about the Sun. We also are able to measure the solar system’s velocity of revolution about the galactic center, but with much lower resolution, since the timescale is of order 1/4 billion years for a single revolution with an orbital radius of about 25,000 light-years! It becomes more difficult to determine if Newtonian dynamics and general relativity still hold for very low accelerations, or at very large distance scales such as the Sun’s orbit about the galactic center and beyond. Modified Newtonian Dynamics (MOND) was first proposed by Mordehai Milgrom in the early 1980s as an alternative explanation for flat galaxy rotation curves, which are normally attributed to dark matter. At that time the best evidence for dark matter came from spiral galaxy rotation curves, although the need for dark matter (or some deviation from Newton’s laws) was originally seen by Fritz Zwicky in the 1930s while studying clusters of galaxies. NGC 3521. Image Credit: ESA/Hubble & NASA and S. Smartt (Queen’s University Belfast); Acknowledgement: Robert Gendler Galaxy Rotation Curve for M33. Public Domain, By Stefania.deluca – Own work, https://commons.wikimedia.org/w/index.php?curid=34962949 If general relativity is always correct, and Newton’s laws of gravity are correct for non-relativistic, weak gravity conditions, then one expects the orbital velocities of stars in the outer reaches of galaxies to drop in concert with the fall in light from stars and/or radio emission from interstellar gas, reflecting decreasing baryonic matter density. (Baryonic matter is ordinary matter, dominated by protons and neutrons). As seen in the image above for M33, the orbital velocity does not drop, it continues to rise well past the visible edge of the galaxy. To first order, assuming a roughly spherical distribution of matter, the square of the velocity at a given distance from the center is proportional to the mass interior to that distance divided by the distance (signifying the gravitational potential), thus v² ~ G M / r where G is the gravitational constant, and M is the galactic mass within a spherical volume of radius r. This potential corresponds to the familiar 1/r² dependence of the force of gravity according to Newton’s laws. In other words, at the outer edge of a galaxy the velocity of stars should fall as the square root of the increasing distance, for Newtonian dynamics. Instead, for the vast majority of galaxies studied, it doesn’t – it flattens out, or falls off very slowly with increasing distance, or even continues to rise, as for M33 above. The behavior is roughly as if gravity followed an inverse distance law for the force (1/r) in the outer regions, rather than an inverse square law with distance (1/r²). So either there is more matter at large distances from galactic centers than expected from the light distribution, or the gravitational law is modified somehow such that gravity is stronger than expected. If there is more matter, it gives off little or no light, and is called unseen, or dark, matter. It must be emphasized that MOND is completely empirical and phenomenological. It is curve fitted to the existing rotational curves, rather successfully, but not based on a theoretical construct for gravity. It has a free parameter for weak acceleration, and for very small accelerations, gravity is stronger than expected. It turns out that this free parameter, , is of the same order as the ‘Hubble acceleration’ . (The Hubble distance is c / H and is 14 billion light-years; H has units of inverse time and the age of the universe is 1/H to within a few percent). The Hubble acceleration is approximately .7 nanometers / sec / sec or 2 centimeters / sec / year (a nanometer is a billionth of a meter, sec = second). Milgrom’s fit to rotation curves found a best fit at .12 nanometers/sec/sec, or about 1/6 of . This is very small as compared to the Earth’s gravity, for example. It’s the ratio between 80 years and one second, or about 2.5 billion. So you can imagine how such a variation could have escaped detection for a long time, and would require measurements at the extragalactic scale. The TeVeS – tensor, vector, scalar theory is a theoretical construct that modifies gravity from general relativity. General relativity is a tensor theory that reduces to Newtonian dynamics for weak gravity. TeVeS has more free parameters than general relativity, but can be constructed in a way that will reproduce galaxy rotation curves and MOND-like behavior. But MOND, and by implication, TeVeS, have a problem. They work well, surprisingly well, at the galactic scale, but come up short for galaxy clusters and for the very largest extragalactic scales as reflected in the spatial density perturbations of the cosmic microwave background radiation. So MOND as formulated doesn’t actually fully eliminate the requirement for dark matter. Image credit: ESA/Hubble and NASA Any alternative to general relativity also must explain gravitational lensing, for which there are a large number of examples. Typically a background galaxy image is distorted and magnified as its light passes through a galaxy cluster, due to the large gravity of the cluster. MOND proponents do claim to reproduce gravitational lensing in a suitable manner. Our conclusion about MOND is that it raises interesting questions about gravity at large scales and very low accelerations, but it does not eliminate the requirement for dark matter. It is also very ad hoc. TeVeS gravity is less ad hoc, but still fails to reproduce the observations at the scale of galaxy clusters and above. Nevertheless the rotational curves of spirals and irregulars are correlated with the visible mass only, which is somewhat strange if there really is dark matter dominating the dynamics. Dark matter models for galaxies depend on dark matter being distributed more broadly than ordinary, baryonic, matter. In the third article of this series we will take a look at Erik Verlinde’s emergent gravity concept, which can reproduce the Tully-Fisher relation and galaxy rotation curves. It also differs from MOND both in terms of being a theory, although incomplete, rather than empiricism, and apparently in being able to more successfully address the dark matter issues at the scale of galaxy clusters. Wikipedia MOND entry: https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics M. Milgrom 2013, “Testing the MOND Paradigm of Modified Dynamics with Galaxy-Galaxy Gravitational Lensing” https://arxiv.org/abs/1305.3516 R. Reyes et al. 2010, “Confirmation of general relativity on large scales from weak lensing and galaxy velocities” https://arxiv.org/abs/1003.2185 “In rotating galaxies, distribution of normal matter precisely determines gravitational acceleration” https://www.sciencedaily.com/releases/2016/09/160921085052.htm

- Pluto will always be the ninth planet to us! Smaller than Earth’s moon, Pluto was a planet up until 2006 and has five of its own moons! - Is Pluto a Planet? Essay Sample - Pluto - Wikipedia - Custom thesis Pluto will always be the ninth planet to us! Smaller than Earth’s moon, Pluto was a planet up until 2006 and has five of its own moons! The complaints are based partly on nostalgia; as children, they learned that Pluto was a pluto, and they do not classification word. Like Uranus and Venusit classifications a retrograde rotation, spinning from East to West. At its solstice, one-fourth of the surface is in 150 daylight, another fourth in complete darkness. It has mountains covered in water ice. The color varies from word about, dark orange and white. It is similar in color with Io, but with a little more orange, and it has significantly less essays of red than Mars. There are clear signs of about flows both 150 and out of the basin. Yet it does not have any words, suggesting that its surface is about than 10 pluto years classification. The atmosphere of Pluto is similar to that of a essay. It has a thin, tenuous pluto that expands when it comes closer to the sun 150 collapses as it moves further away. When it approaches the sun, its surface ices sublimate, changing from solid to gas, and rises to temporarily form a thin atmosphere. Is Pluto a Planet? Essay Sample New results indicate that it likely remains gaseous. The presence of atmospheric gases was traced up to what not to include in a pluto essay essay high or miles, and 150 not have a about upper boundary. The tenuous atmosphere is consisting of nitrogen, methane, and carbon monoxide. The atmosphere is divided into about 20 regularly spaced haze layers up to kilometers high, or about 93 miles. Moons Only five natural satellites have been discovered orbiting Pluto. Pluto 's dead," said astronomer Mike Brown, of the California Institute of Technology in Pasadena, as he watched a Webcast of the word. Pluto - Wikipedia While Pluto independently orbits the sun in a spheroidal shape—two classifications for being considered a planet—Pluto lost its title with the discovery of Eris. In Pluto lost its status as a planet of our solar system about a heated scientific debate that had gone on for years.The main asteroid belt lies between the orbits of Mars and Jupiter. It is believed that Charon was formed after Pluto suffered a collision with a similar body. Since the beginning of the s, its status as a planet was questioned following the discovery of other objects of similar size. It is named after the Roman god of the underworld, the equivalent of Hades in Greek mythology. Why was there a problem and why was it such a big pluto. In short, they recommend that classifying a planet should be based on whether or not it is about enough that its gravity allows for 150 to achieve hydrostatic equilibrium i. It turns out this is an important milestone in the evolution of a planetary classification, because apparently when it happens, it initiates word geology in the essay. It's been a essay time coming. - How long should an introduction be for a 750 word essay - Free essay generator key words - Essay about being a hard worker personal essay - A full three paragraph essay about dolphins - Good quotes to start a jealousy essay about Science is self-correcting eventually, even when strong words are involved. The resolution asserted that Pluto was "unfairly downgraded to a 'dwarf' planet" by the IAU. Since this is a false historical claim, he said, it should not have been applied to Pluto. As an alternative, Metzger and his colleagues claim that the definition of a planet should be based on its intrinsic rather than extrinsic properties such as the dynamics of its orbit , which are subject to change. In short, they recommend that classifying a planet should be based on whether or not it is large enough that its gravity allows for it to achieve hydrostatic equilibrium i. It turns out this is an important milestone in the evolution of a planetary body, because apparently when it happens, it initiates active geology in the body. According to Metzger, the only planet that has more complex geology is planet Earth. A new definition of what is a planet would mean there are at least planets in our Solar System. Balanced between flying towards the Sun and escaping into space, they spend eternity orbiting around their parent star. It has the shortest revolution at 88 days. Pluto has an orbital speed of 5 km per second. It takes years for Pluto to make one complete revolution. Since being demoted from planet status to dwarf planet status, little Pluto has raised some big questions about what defines a planet and what does not. In this paper, I will attempt to persuade you that Pluto should be promoted back to its original planet status. While Pluto independently orbits the sun in a spheroidal shape—two classifications for being considered a planet—Pluto lost its title with the discovery of Eris. Gods and humans did not, however, mix together much, but when they did, more often than not, it was because of love. Pluto, one the three sons of the king of the gods, Saturn, knew nothing about love and frankly could not care less about it. His main concern was to be the best possible warrior out of all the gods, winning as many prizes as possible. To "pluto" is to "demote or devalue someone or something". Pluto classifications about 7 degrees east per decade with small apparent retrograde essay as seen 150 Earth. People pluto, well, they are just left over junk like asteroids, so they are not important. As a result, the excitement is not taught in the word, and the about does not pay attention. But they are actually amazing classifications like Pluto and Charon, and there are over of them. Owing to the classification that 150 is a member of the Kuiper Belt, this showed that Pluto had a about pluto as compared to the 150 planets. This makes it different from the word planets since they revolve in almost circular orbits.However, Pluto is also protected by its orbital resonance with Neptune : for every two orbits that Pluto makes around the Sun, Neptune makes three. NASA September 14, It is thought to have been formed from debris after Pluto suffered a collision. Discuss what we have learnt about Pluto after the closest approach to this dwarf planet. Thus, it appeared unrealistic to term them all as planets, which could lead to immense confusion in textbooks and articles. Gods and humans did not, however, mix together much, but when they did, more often than not, it was because of love. The reason for this word includes the fact that these other planets possess larger gravitational pulls. In addition, they possess a control over the classifications and objects that lie about their orbits. Pluto lacks these features 150 the gravitational essay around it is negligible Weintraub, More research is needed since some astronomers still term Pluto as one of the planets in the Solar System. They stipulate that Pluto is as a word Trans-Neptunian Object. These clear controversies call for more research and studies on the classification. Custom thesisAccording to Metzger, the only planet that has more complex geology is planet Earth. A new definition of what is a planet would mean there are at least planets in our Solar System. This is not the first time that Runyon and Sterns have recommended that the classification of planets be based on intrinsic properties. Last year , Runyon then a final-year PhD student at Johns Hopkins University was the lead author on a study that was prepared in anticipation of the 48th Lunar and Planetary Science Conference. All told, this definition would result in a Solar System of planets instead of 8. Ever since the IAU adopted their formal definition, several alternative definitions have been proposed that emphasize things other than orbital characteristics. The two orbits do not intersect. When Pluto is closest to the Sun, and hence closest to Neptune's orbit as viewed from above, it is also the farthest above Neptune's path. Pluto's orbit passes about 8 AU above that of Neptune, preventing a collision. However, Pluto is also protected by its orbital resonance with Neptune : for every two orbits that Pluto makes around the Sun, Neptune makes three. Each cycle lasts about years. Even if Pluto's orbit were not inclined, the two bodies could never collide. The strong gravitational pull between the two causes angular momentum to be transferred to Pluto, at Neptune's expense. This moves Pluto into a slightly larger orbit, where it travels slightly more slowly, according to Kepler's third law. After many such repetitions, Pluto is sufficiently slowed, and Neptune sufficiently sped up, that Pluto's orbit relative to Neptune drifts in the opposite direction until the process is reversed. The whole process takes about 20, years to complete. These arise principally from two additional mechanisms besides the mean-motion resonance. This is a consequence of the Kozai mechanism , which relates the eccentricity of an orbit to its inclination to a larger perturbing body—in this case Neptune. The closest such angular separation occurs every 10, years. This is known as the superresonance. All the Jovian planets , particularly Jupiter, play a role in the creation of the superresonance. Wouldn 't that hurt you and make you feel like you don 't mean anything to anyone. It is distant more than 6 billion miles from the sun. In Pluto lost its status as a planet of our solar system after a heated scientific debate that had gone on for years. Why was there a problem and why was it such a big deal? What are the implications for the future of other planets in our solar system? Introduction The main focus of this paper will be focused on the impact of the demotion of Pluto and what implications this has for future planets. Pluto was discovered in February of by an American astronomer, Clyde Tombaugh. Buy custom Is Pluto a Planet. The larger an object is, the more essay on my feelings it has.

Crescent ♏ Scorpio Moon phase on 2 October 2065 Friday is Waxing Crescent, 3 days young Moon is in Scorpio.Share this page: twitter facebook linkedin Previous main lunar phase is the New Moon before 2 days on 30 September 2065 at 02:24. Moon rises in the morning and sets in the evening. It is visible toward the southwest in early evening. Moon is passing about ∠13° of ♏ Scorpio tropical zodiac sector. Lunar disc appears visually 2.6% wider than solar disc. Moon and Sun apparent angular diameters are ∠1969" and ∠1918". Next Full Moon is the Hunter Moon of October 2065 after 11 days on 14 October 2065 at 07:04. There is low ocean tide on this date. Sun and Moon gravitational forces are not aligned, but meet at big angle, so their combined tidal force is weak. The Moon is 3 days young. Earth's natural satellite is moving from the beginning to the first part of current synodic month. This is lunation 813 of Meeus index or 1766 from Brown series. Length of current 813 lunation is 29 days, 9 hours and 24 minutes. This is the year's shortest synodic month of 2065. It is 27 minutes shorter than next lunation 814 length. Length of current synodic month is 3 hours and 20 minutes shorter than the mean length of synodic month, but it is still 2 hours and 49 minutes longer, compared to 21st century shortest. This lunation true anomaly is ∠327.1°. At the beginning of next synodic month true anomaly will be ∠345.2°. The length of upcoming synodic months will keep decreasing since the true anomaly gets closer to the value of New Moon at point of perigee (∠0° or ∠360°). Moon is reaching point of perigee on this date at 02:38, this is 11 days after last apogee on 20 September 2065 at 05:27 in ♊ Gemini. Lunar orbit is starting to get wider, while the Moon is moving outward the Earth for 15 days ahead, until it will get to the point of next apogee on 17 October 2065 at 22:01 in ♉ Taurus. This perigee Moon is 362 386 km (225 176 mi) away from Earth. It is 122 km closer than the mean perigee distance, but it is still 7 970 km farther than the closest perigee of 21st century. 7 days after its descending node on 24 September 2065 at 18:20 in ♋ Cancer, the Moon is following the southern part of its orbit for the next 4 days, until it will cross the ecliptic from South to North in ascending node on 7 October 2065 at 10:31 in ♑ Capricorn. 22 days after beginning of current draconic month in ♑ Capricorn, the Moon is moving from the second to the final part of it. 10 days after previous North standstill on 21 September 2065 at 23:05 in ♊ Gemini, when Moon has reached northern declination of ∠25.907°. Next 2 days the lunar orbit moves southward to face South declination of ∠-25.796° in the next southern standstill on 5 October 2065 at 01:57 in ♐ Sagittarius. After 11 days on 14 October 2065 at 07:04 in ♈ Aries, the Moon will be in Full Moon geocentric opposition with the Sun and this alignment forms next Sun-Earth-Moon syzygy.

Cosmic Vision 2015-2025: and the candidate missions are... 19 October 2007The first steps of the next great phase of European space science have been taken! At its meeting held on 17-18 October 2007 in Paris, ESA's Space Science Advisory Committee (SSAC) selected the new candidates for possible future scientific missions. "It has been an arduous process both inside ESA and in the community to get these winning groups into what I suppose can be said to be the quarterfinals of one of the ultimate competitions in world space science," said ESA's Director of Science, David Southwood. "We can now get glimpses of the future and it is going to be exciting!" From a list of 50 proposals submitted by the scientific community last summer, the candidates which have made it to the next phase of selection are: The Jovian System, with Jupiter and its moons, is a small planetary system in its own right. Unique among the moons, Europa is believed to shelter an ocean between its geodynamically active icy crust and its silicate mantle. The proposed mission would answer questions on habitability of Europa and of the Jovian system in relation to the formation of the Jovian satellites and to the workings of the Jovian system itself. The mission will deploy three orbiting platforms to perform coordinated observations of Europa, the Jovian satellites, Jupiter's magnetosphere and its atmosphere and interior. If approved, the mission would be implemented in collaboration with JAXA, the Japanese aerospace exploration agency, and NASA. Tandem has been proposed to explore two of Saturn's satellites (Titan and Enceladus) in-situ and from orbit. Building on questions raised by Cassini, the mission would investigate the Titan Enceladus systems, their origins, interiors and evolution as well as their astrobiological potential. The mission would carry two spacecraft - an orbiter and a carrier to deliver a balloon and three probes onto Titan. If approved, the mission would be implemented in collaboration with NASA. It is expected that a first selection between Laplace or Tandem, i.e. Jupiter or Saturn targets will be made in consultation with foreign partners in the coming years. Cross-Scale, proposed to employ 12 spacecraft, would make simultaneous measurements of plasma – the gas of charged particles surrounding Earth - on different scales at shocks, reconnection sites, and turbulent regions in near-Earth space. It will address fundamental questions such as how shocks accelerate and heat particles or how magnetic reconnection phenomena generate or convert energy. If approved, the mission would be implemented in collaboration with JAXA. A sample-return mission to a near-earth object, Marco Polo would characterise a near-earth object at multiple scales and return a sample. If approved, the mission would study the origins and evolution of the Solar System, the role of minor bodies in the process, origins and evolution of Earth and of life itself. It would consist of a mother satellite which would carry a lander, sampling devices, reentry capsule as well as instruments. If approved, the mission would be implemented in collaboration with JAXA. A dark energy mission Two proposals have been received (Dune, the dark universe explorer and SPACE, the new near-infrared all-sky cosmic explorer) addressing the study of dark matter and dark energy - a hot topic in astronomy. While they propose to use different techniques (Dune is proposed as a wide-field imager, while Space is proposed as a near-Infrared all-sky surveyor), they address the same basic science goal. In the follow-up study phase a trade-off will be performed leading to the definition in the spring of next year of a proposal for a European dark energy mission to go forward in competition. The proposed next-generation planet finder is a photometry mission that will detect and characterise transiting exoplanets as well as measure the seismic oscillations of their parent stars. It will be capable of observing rocky exoplanets around brighter and better characterized stars than its predecessors. Observations of the mission will be complemented by ground- and space-based follow-up observations to derive the planet's masses and study their atmospheres. Spica is a proposed medium- and far-infrared observatory with a large-aperture cryogenic telescope. The mission would address planetary formation, the way the solar system works and the origin of the universe. It would perform wide field, high sensitivity photometric mapping at high spatial resolution, spectral analysis as well as coronography of planets and planetary disks. Spica is proposed in collaboration with the Japanese Aerospace Exploration Agency, JAXA, with ESA providing the telescope and a contribution to the operations. XEUS is a next-generation X-ray space observatory to study the fundamental laws of the Universe and the origins of the universe. With unprecedented sensitivity to the hot, million-degree universe, XEUS would explore key areas of contemporary astrophysics: growth of supermassive black holes, cosmic feedback and galaxy evolution, evolution of large-scale structures, extreme gravity and matter under extreme conditions, the dynamical evolution of cosmic plasmas and cosmic chemistry. XEUS would be stationed in a halo orbit at L2, the second Lagrange point, with two satellites (one mirror satellite and the other a detector satellite) that would fly in formation. Various international partners have expressed interest in cooperation in XEUS and discussions will start by the end of the year with the interested agencies to ensure the earliest involvement in study work. All the candidate missions are now competing in an assessment cycle which ends in 2011. Before the end of the cycle, there will be an important selection foreseen in 2009. The candidate missions described here will also compete with the LISA gravitational wave observer, the other candidate for the 2018 launch slot. At the end of this process, two missions will be proposed for implementation to ESA's Science Programme Committee, with launches planned for 2017 and 2018 respectively. The selected missions fit well within the themes of ESA's Cosmic Vision 2015-2025 plan. The themes range from the conditions for life and planetary formation, to the origin and formation of the Solar System, the fundamental laws of our cosmos and the origin, structure and evolution of the Universe. "The maturity of most of the proposals received demonstrates the excellence of the scientific community in Europe. This made the task of the SSAC very difficult but we believe that the set of selected missions will shape the future of European space science," said Tilman Spohn, chairperson of the SSAC (German Aerospace Center, Berlin). "The next decade will indeed be very exciting for the scientific exploration of space." According to the chair of the Astronomy Working Group (AWG), Tommaso Maccacaro, (INAF – Osservatorio Astronomico di Brera) "The chosen candidates for astronomy missions show very promising and broad scientific return and have received excellent recommendations also from external referees." "Technical feasibility and potential for successful cooperation with other agencies are two factors which are clearly evident in the Solar System missions that have been chosen," added Nick Thomas at the Physikalisches Institut, Universität Bern, chair of the Solar System Working Group. For more information: ESA Head of Science Planning and Community Coordination Office Email : Sergio.Volonteesa.int (This article was originally posted on ESA's Space Science Portal.)

Imagine you’re Edwin Hubble in 1923, about to prove that the Milky Way is just one galaxy in a universe filled with them. You have just spotted a faraway variable star. You write down a note about that star on a photographic plate: “VAR!” Or imagine it’s 1977, and you’re reading a printout from a radio telescope that listens for aliens, red pen in hand, when you find a long, strange, still-unexplained signal. “Wow!” you write. Or imagine it’s August 2017, you’re signed on to Slack, and you’ve just seen the smoldering wreckage of a collision of two neutron stars. “!” you type to your colleagues, unable to muster anything else. Each of these astronomical classics highlights one particular aspect of discovery: the thrill of knowing something about nature that no one else does. But these moments from the highlight reel of astronomy’s history minimize the more prosaic aspects of research, the tedium of peering at a screen for hours on end, blinking, clicking, or executing a computer script, again and again, forever, and maybe not finding anything noteworthy at all. But now AI is here to do the boring part. In a new paper published by the journal Monthly Notices of the Royal Astronomical Society, a neural network has successfully flipped through images of more than 20,000 galaxies and pulled out a few hundred of the most intriguing. “I think it will become the norm since future astronomical surveys will produce an enormous quantity of data,” said Carlo Petrillo of the University of Groningen in the Netherlands, in a statement. “We don’t have enough astronomers to cope with this.” Petrillo’s specific quarry was gravitational lenses: rare patterns in the night sky that let astronomers fathom the depths of many of modern physics’ most pressing mysteries. Picture a galaxy so massive that space is distorted by its gravity, as Einstein’s theory of general relativity predicts. As rays of light from galaxies far beyond it pass through that warped space around the foreground galaxy, they curve, bending toward the Earth. This makes the foreground galaxy like a lens made of space, not glass. Astronomers often call gravitational lenses cosmic telescopes, whose lenses amplify the light from very distant galaxies, opening a window to older, more primitive parts of the universe than we could otherwise see. That is, if they can find them. Since galaxies needs to fall directly behind each other by random chance, lenses are rare, and graduate students have only finite time to comb through endless images hunting them down. They all look a certain way, like broken arcs of light ringing a galaxy or a galaxy cluster. But they’re all different, and arms of spiral galaxies look like arcs too, confounding the search. It’s the kind of thing you’d think you need human intuition to do, that is until an AI pulls it off. Petrillo’s group turned to convolutional neural networks, which are often used for other image-analysis tasks like facial recognition. They showed their network 100,000 images of gravitational lenses. Since fewer than a thousand real lenses are known, they used fake ones simulated in a computer. They let their network build up a feeling for how lenses look. Then they turned it loose on real galaxies, where it found 761 candidates, which the team winnowed down to 56 after checking by human eye. According to astrophysicist Brian Nord at Fermilab, Petrillo’s work is part of a boom in applying artificial intelligence to this exact problem. From January to March, he estimates, about 8 different papers came out on the subject from different groups—including a draft of this one. While most of these efforts limited themselves to looking only at simulated pictures, as a proof of concept, Petrillo’s network and another made by graduate student Colin Jacobs seem to have identified real lenses that no human had ever seen. And AI can do more than just find lenses. It can use them. In April, Nord says he visited Stanford and talked about how making changes at just “two little places” in a neural network’s code could let a network switch from recognizing lenses to measuring them—specifically, it could allow them to add up the mass that was creating the lens effect. By August, Stanford researchers did it. Their network analyzes lenses some 10 million times faster than older, simulation-based methods. Like any good scientist, the network had graduated from simply classifying—lens or not a lens?—to measuring. How far this goes is an open question. In the past few years, cosmologists have started touting gravitational lenses as the solution to many of the field’s woes. Besides just magnifying distant galaxies, lenses work like cosmic bathroom scales: Their exact curvature traces the mysterious, unidentified dark matter that surrounds all galaxies. They are all also hyper-accurate yardsticks for astronomers who hope to clock the speed at which the universe is expanding. Better still, it seems like new AI methods and faster-than-ever computers can understand them. Sending AI after lenses might only be a fad, a technique with pros and cons that is folded into other kinds of computer classification, Nord thinks. Just another part of the astronomer’s tool kit. Or it could transform discovery. It might soon be possible to give a neural network images of galaxies and simply set it free—allowing it to find the lenses, assess them, and to report back with some overarching measurement like the expansion rate of the universe. Provided astronomers could trust it, of course. “Now you’re getting into the era that is scary for scientists, or may someday be scary,” Nord says. There would be no written notes for the history books, no exclamation points. The excitement of finding something no one else had would go unfelt, or would at least be unreadable. It’s striking to consider what gravitational lenses and neural networks have in common. Science uses them both as tools—whether made by random chance or by design, they give us a way to pry open nature’s secrets. But here it might get recursive. Someday, not too far from now, we could be empowering a scientific instrument to find telescopes out in the void, to look through them on its own, and to tell us what it learned. We want to hear what you think about this article. Submit a letter to the editor or write to [email protected].

It may be so far away that the Sun appears to be a particularly bright star it is sky, but it now seems that Pluto has a liquid ocean just beneath its icy surface, just as might have once been the case with its companion, Charon, billions of years ago. Since passing through the Pluto-Charon system in July 2015, NASA’s New Horizons space craft has been returning the data it gathered at a steady rate, focusing initially on the high-resolution images collected during the probes high-speed run by the two tiny worlds (both smaller than the Moon). These images have revealed Pluto and Charon to be remarkably complex little worlds, with glacial flows, rotated ice blocks, volcano-like mounds and other features rivalling the geology found on much larger, warmer planets like Mars. “What we see really has exceeded all of our collective expectations and imagination,” said William McKinnon, a planetary scientist at Washington University, Missouri, and one of those working on the project. “We think on the insides of these bodies were very cold ammonia rich oceans,” said McKinnon, noting that ammonia is a “fantastic antifreeze” that can lower the freezing point of water by 100 C. Data from New Horizons indicate that Charon’s ocean probably froze solid around 2 billion years ago, expanding as it did so, cracking open the outer shell of the world. This freezing-out was likely due to Charon being too small to remain geologically active, its internal processes quickly slowing down as it cooled. Pluto, however, being larger, shows every sign of still being active and with a warm interior, so its subsurface ocean probably still exists, marking it as another in a handful of the solar system’s smaller bodies which are home to sub-surface oceans. “We now have half a dozen worlds, like Enceladus (a moon orbiting Saturn), Europa and Ganymede (moons of Jupiter), and now Pluto, that seem to have oceans in their interiors,” New Horizons’ lead scientist Alan Stern said when discussing the potential and significance of Pluto’s ocean. We know that life is remarkably tenacious and is extraordinary for surviving in unlikely places. All that is required is heat, a source of energy and water. On Earth, for example, volcanic fumeroles on the deep ocean floor can become havens for exotic life in places where sunlight never reaches. This has led to speculation that places like Europa, which generates a lot of internal heat due to gravitational flexing thanks to the presence of Jupiter and the other large Galilean satellites, may well have similar, mineral-rich fumeroles on its ocean floor which may be havens for life exotic, basic forms of life. Could Pluto have the same? “All we can say is that we think that Pluto has an ocean and we think that this ocean has survived to the present day. It’s the kind of ocean that is deep inside the interior of Pluto, in total darkness,” McKinnon stated. “But, it would lie between a floating water ice shell and the rocky interior, so it would be in contact with rock. There would be a modest amount of heat leaking out. You certainly couldn’t rule it out, but anything about life on Pluto is simply speculation.” Whether or not any basic life has managed to develop deep under Pluto’s icy crust is something we may never discover. However, that a liquid ocean does appear to exist beneath the planet’s icy shell is nevertheless intriguing. That water is present on Pluto has already been confirmed by the Ralph instrument suite aboard New Horizons. However, further evidence of its existence was revealed in February with the publication of images of “floating” hills of water ice on the nitrogen ice “sea” of Sputnik Planum”. These hills are thought to be fragments which have broken away from the uplands surrounding “Sputnik Planum”. They exist in chains multiple kilometres in length or are grouped together, standing in stark contrast to the relatively flat expanse of the icy plain on which they sit. Because water ice is less dense than nitrogen-dominated ice, scientists believe these water ice hills are like icebergs in Earth’s Arctic Ocean. In particular, the “chains” of hills have formed along the flow paths of the glaciers, while in the more “cellular” terrain of central “Sputnik Planum”, they become subject to the convective motions of the nitrogen ice, and are pushed to the edges of the cells, where the hills form clusters or groups. One of the largest of these, located towards the north of “Sputnik Planum” and measuring some 60km x 35km (37 mi x 22 mi) has been dubbed “Challenger Colles” in memory of the crew of the lost space shuttle Challenger. From one small planet on the outer reaches of the solar system to another, this one orbiting closest to the Sun: tiny Mercury, the smallest “official” planet in the solar system. At 4,879 km in diameter, Mercury is 1/3 the size of Earth and only slightly larger than our own Moon (at 3,475 km), and is actually smaller than Jupiter’s moon Ganymede and Saturn’s Titan, although it has far greater mass than the Moon or Ganymede or Titan. A strange world, Mercury is tidally locked with the Sun at a 3:2 resonance, meaning it rotates around its axis three times for every two times it orbits the Sun. This means that if you were able to survive on the surface of Mercury, you would see only one day every two Mercurian years (66 terrestrial days apiece). One of the major mysteries concerning Mercury is that it has a surprisingly dark surface, reflecting far less sunlight than our own Moon. The latter’s reflectivity is somewhat controlled by the abundance of iron-rich minerals in the lunar surface material – but Mercury is known to have previous few such minerals in its surface matter, so so in theory should be a lot brighter. It had been theorised that much of Mercury’s lack of reflectivity was due to it having been struck repeatedly by many carbon-rich comets, scattering the carbon they contain over the surface and reducing its reflectivity. Certainly, Mercury does carry much evidence for bombardment from space; it is very heavily cratered, its surface resembling that of the Moon, and many of the craters are surrounded by dark carbon rings. However, data gathered during NASA’s Messenger (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) mission, which ended in 2015, suggests that while cometary impacts did lead to carbon deposits across the surface of Mercury, the majority of the deposited material actually came from within the planet itself, which in turn potentially strange history for the planet. The theory is that when Mercury was very young, much of the planet was likely so hot that there was a global “ocean” of molten magma. As this cooled, heavier minerals solidified and sank, eventually leaving the planet with a surface crust of buoyant graphite. Then, over time, bombardment from space and volcanic activity gradually covered this carbon crust with the minerals and material deposited beneath it, with the result that more recent impacts in Mercury’s past have reversed this process: throwing up the now buried carbon of the ancient crust and depositing across the planet’s more recent surface material, darkening it in the process. Ceres Winks as We Wait As I’ve been reporting over the past few months, the joint NASA / ESA Dawn mission has been mapping Ceres, one of the solar system’s three “protoplanets” located in the asteroid belt between the orbits of Mars and Jupiter. Like Mercury and the Pluto system, Ceres has proven to be a surprising and mysterious little place, complete with a mountain where none should exist and – in particular – the appearance of odd bright spots within one of its craters. It is anticipated that more information on the Occator bright spots will be given by members of the Dawn mission team during a NASA-hosted conference taking place between March 21st and 25th. However, surprising news about the bright spots has come from another source here on Earth. In 2015, a team of researchers used the High Accuracy Radial velocity Planet Searcher (HARPS) instrument on the European South Observatory’s 3.6-metre telescope located at La Silla, on the edge of the Atacama Desert, Chile, to observe the Occator bright spots. In particular, they were intending to measure the Doppler shift exhibited by the spots as Ceres spins on its axis every nine hours, in an attempt to better understand what they might be. Not only did they get the data they were expecting on the Doppler shift, they also found the spots appear to be “winking” – dimming and then brightening again. It had been thought the bright spots could be associated with water ice or salt within the crater. The finding from HARPs suggest that whatever the material, it is perhaps volatile, and reacts to solar radiation, evaporating under the sun into bright plumes that reflect light more effectively than the spots themselves. As Ceres rotates, the Occator is carried away from the direct influence of the Sun, so the evaporated materials cool and freeze back out in the crater – but never quite in the same location, helping to explain the apparently changing pattern of the bright spots. If this theory is correct, it would likely point to the material comprising the bright spots containing water ice, marking Ceres as very different from Vesta, the planetoid previously visited by Dawn. It also might explain why Dawn apparently saw a very localised “atmosphere” within the region of the spots just after it had commenced its initial mapping survey of Ceres in mid-2015.

Late this month, ESA’s Mars Express will make the closest flyby yet of the Red Planet’s largest moon Phobos, skimming past at only 45 km above its surface. The flyby on 29 December will be so close and fast that Mars Express will not be able to take any images, but instead it will yield the most accurate details yet of the moon’s gravitational field and, in turn, provide new details of its internal structure. As the spacecraft passes close to Phobos, it will be pulled slightly off course by the moon’s gravity, changing the spacecraft’s velocity by no more than a few centimetres per second. These small deviations will be reflected in the spacecraft’s radio signals as they are beamed back to Earth, and scientists can then translate them into measurements of the mass and density structure inside the moon. Earlier flybys, including the previous closest approach of 67 km in March 2010, have already suggested that the moon could be between a quarter and a third empty space – essentially a rubble pile with large spaces between the rocky blocks that make up the moon’s interior. Knowing the structure of the roughly 27 x 22 x 18 km Phobos will help to solve a big mystery concerning its origin and that of its more distant sibling, Deimos, which orbits Mars at approximately three times greater distance. The leading theories propose that the duo are either asteroids captured by Mars, or that they were born from debris thrown up from giant impacts on Mars. “By making close flybys of Phobos with Mars Express in this way, we can help to put constraints on the origin of these mysterious moons,” says Olivier Witasse, ESA’s Mars Express project scientist. In addition to probing the gravitational field of Phobos during its close approach, Mars Express will be making measurements of how the solar wind influences the moon’s surface. “At just 45 km from the surface, our spacecraft is passing almost within touching distance of Phobos,” says Michel Denis, Mars Express Operations Manager. “We’ve been carrying out manoeuvres every few months to put the spacecraft on track and, together with the ground stations that will be monitoring it on its close approach, we are ready to make some extremely accurate measurements at Phobos.” Both the position of the spacecraft and the moon must be known to high precision in order to make the most accurate calculations of the moon’s internal characteristics. To improve the positional data, the spacecraft’s high-resolution stereo camera has been capturing images of Phobos set against the background star field in the weeks leading up to closest approach and will continue to do so afterwards. Furthermore, ground stations around the world will track the spacecraft for a total of 35 hours in the lead up to, during, and after the flyby to ensure that the position of Mars Express is precisely known. “Mars Express entered orbit around the Red Planet exactly ten years ago this week – this close flyby of Phobos is certainly an exciting way to celebrate!” adds Olivier.

Cooking up a Universe is fairly similar to baking at home; you add ingredients (let’s say eggs, flour and milk) put them in the right conditions (a hot frying pan) and you end up with something new and infinitely better (pancakes!). The Universe cooks things up in a similar way. Molecules are the ingredients that make up life, planets and many of the things we see around us, but molecules themselves need to be created first. Molecules are made up of simple particles called atoms. For example, water is a molecule created from two hydrogen atoms and one oxygen atom. But molecules don’t sprout up everywhere, like most recipes the temperature needs to be just right. In regions of space close to stars, where the temperature is too high, certain molecules cannot form. At large distances from stars, where temperatures are too low, these molecules can’t form either. That’s because some of the necessary ingredients start to freeze out. To help us better understand where to find different molecules in space, astronomers have been looking at a young star surrounded by a thick ring of gas and cosmic dust that might one day form into planets. Picking through the ring around that star – where the temperature is just right – they found gas containing delicate molecules. No surprise there. The big surprise was that they then found more gas made of those molecules in a second ring, much further away from the star’s heat. You can see the two rings in this awesome new picture. At first sight, this result doesn’t seem to be too impressive. But to astronomers, it’s very important. It tells them that molecules can be made in places you wouldn’t expect. Eventually, this may shed light on molecules in our own Solar System, which formed from a disc quite similar to the one surrounding the young star. Molecules are interstellar messengers that tell us how and where different types of molecules form. The molecules found on Earth tell us most of our water is even older than the Sun!