[meteorite-list] NASA's Kepler Gets the 'Big Picture' of Comet 67P
http://www.jpl.nasa.gov/news/news.php?feature=6641 NASA's Kepler Gets the 'Big Picture' of Comet 67P Jet Propulsion Laboratory October 7, 2016 On Sept. 30, the European Space Agency concluded its Rosetta mission and the study of comet 67P/Churyumov-Gerasimenko. During the final month of the mission, NASA's planet-hunting Kepler spacecraft had a unique opportunity to provide a "big picture" view of the comet as it was unobservable from Earth. Ground-based telescopes could not see comet 67P, because the comet's orbit placed it in the sky during daylight hours. >From Sept. 7 through Sept. 20, the Kepler spacecraft, operating in its K2 mission, fixed its gaze on comet 67P. From the distant vantage point of Kepler, the spacecraft could observe the comet's core and tail. The long-range global view of Kepler complements the close-in view of the Rosetta spacecraft, providing context for the high-resolution investigation Rosetta performed as it descended closer and closer to the comet. During the two-week period of study, Kepler took a picture of the comet every 30 minutes. The animation shows a period of 29.5 hours of observation from Sept. 17 through Sept. 18. The comet is seen passing through Kepler's field of view from top right to bottom left, as outlined by the diagonal strip. The white dots represent stars and other regions in space studied during K2's tenth observing campaign. As a comet travels through space, it sheds a tail of gas and dust. A comet's activity level can be obtained by measuring the reflected sunlight. Analyzing the Kepler data, scientists will be able to determine the amount of mass lost each day as comet 67P travels through the solar system. NASA Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory, Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. For more information on Kepler and the K2 missions, go to: www.nasa.gov/kepler For more information on Rosetta, go to: https://www.nasa.gov/rosetta/ News Media Contact Elizabeth Landau Jet Propulsion Laboratory, Pasadena, Calif. 818-354-6425 elizabeth.lan...@jpl.nasa.gov Michele Johnson Ames Research Center, Moffett Field, Calif. 650-604-6982 michele.john...@nasa.gov Written by Michele Johnson 2016-260 __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] NASA's Opportunity Rover to Explore Mars Gully
http://www.jpl.nasa.gov/news/news.php?feature=6642 NASA's Opportunity Rover to Explore Mars Gully Jet Propulsion Laboratory October 7, 2016 NASA's Opportunity Mars rover will drive down a gully carved long ago by a fluid that might have been water, according to the latest plans for the 12-year-old mission. No Mars rover has done that before. The longest-active rover on Mars also will, for the first time, visit the interior of the crater it has worked beside for the last five years. These activities are part of a two-year extended mission that began Oct. 1, the newest in a series of extensions going back to the end of Opportunity's prime mission in April 2004. Opportunity launched on July 7, 2003 and landed on Mars on Jan. 24, 2004 (PST), on a planned mission of 90 Martian days, which is equivalent to 92.4 Earth days. "We have now exceeded the prime-mission duration by a factor of 50," noted Opportunity Project Manager John Callas of NASA's Jet Propulsion Laboratory, Pasadena, California. "Milestones like this are reminders of the historic achievements made possible by the dedicated people entrusted to build and operate this national asset for exploring Mars." Opportunity begins its latest extended mission in the "Bitterroot Valley" portion of the western rim of Endeavour Crater, a basin 14 miles (22 kilometers) in diameter that was excavated by a meteor impact billions of years ago. Opportunity reached the edge of this crater in 2011 after more than seven years of investigating a series of smaller craters. In those craters, the rover found evidence of acidic ancient water that soaked underground layers and sometimes covered the surface. The gully chosen as the next major destination slices west-to-east through the rim about half a mile (less than a kilometer) south of the rover's current location. It is about as long as two football fields. "We are confident this is a fluid-carved gully, and that water was involved," said Opportunity Principal Investigator Steve Squyres of Cornell University, Ithaca, New York. "Fluid-carved gullies on Mars have been seen from orbit since the 1970s, but none had been examined up close on the surface before. One of the three main objectives of our new mission extension is to investigate this gully. We hope to learn whether the fluid was a debris flow, with lots of rubble lubricated by water, or a flow with mostly water and less other material." The team intends to drive Opportunity down the full length of the gully, onto the crater floor. The second goal of the extended mission is to compare rocks inside Endeavour Crater to the dominant type of rock Opportunity examined on the plains it explored before reaching Endeavour. "We may find that the sulfate-rich rocks we've seen outside the crater are not the same inside," Squyres said. "We believe these sulfate-rich rocks formed from a water-related process, and water flows downhill. The watery environment deep inside the crater may have been different from outside on the plain -- maybe different timing, maybe different chemistry." The rover team will face challenges keeping Opportunity active for another two years. Most mechanisms onboard still function well, but motors and other components have far exceeded their life expectancy. Opportunity's twin, Spirit, lost use of two of its six wheels before succumbing to the cold of its fourth Martian winter in 2010. Opportunity will face its eighth Martian winter in 2017. Use of Opportunity's non-volatile "flash" memory for holding data overnight was discontinued last year, so results of each day's observations and measurements must be transmitted that day or lost. In the two-year extended mission that ended last month, Opportunity explored the "Marathon Valley" area of Endeavour's western rim, documenting the geological context of water-related minerals that had been mapped there from orbital observations. Last month, the rover drove through "Lewis and Clark Gap," a low point in the wall separating Marathon Valley from Bitterroot Valley. A recent color panorama from the rover features "Wharton Ridge," which extends eastward from the gap. This week, Opportunity is investigating rock exposures next to "Spirit Mound," a prominent feature near the eastern end of Bitterroot Valley. The third main science goal of the new extended mission is to find and examine rocks from a geological layer that was in place before the impact that excavated Endeavour Crater. The science team has not yet determined whether the mound area will provide rocks that old. Opportunity and NASA's next-generation Mars rover, Curiosity, as well as three active NASA Mars orbiters, and surface missions to launch in 2018 and 2020 are steps in NASA's Journey to Mars, on track for sending humans there in the 2030s. JPL, a division of Caltech in Pasadena, California, built Opportunity and manages the mission for NASA's Science Mission Directorate,
[meteorite-list] Study Predicts Next Global Dust Storm on Mars
http://www.jpl.nasa.gov/news/news.php?feature=6638 Study Predicts Next Global Dust Storm on Mars Jet Propulsion Laboratory October 5, 2016 Global dust storms on Mars could soon become more predictable -- which would be a boon for future astronauts there -- if the next one follows a pattern suggested by those in the past. A published prediction, based on this pattern, points to Mars experiencing a global dust storm in the next few months. "Mars will reach the midpoint of its current dust storm season on October 29th of this year. Based on the historical pattern we found, we believe it is very likely that a global dust storm will begin within a few weeks or months of this date," James Shirley, a planetary scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. Local dust storms occur frequently on Mars. These localized storms occasionally grow or coalesce to form regional systems, particularly during the southern spring and summer, when Mars is closest to the sun. On rare occasions, regional storms produce a dust haze that encircles the planet and obscures surface features beneath. A few of these events may become truly global storms, such as one in 1971 that greeted the first spacecraft to orbit Mars, NASA's Mariner 9. Discerning a predictable pattern for which Martian years will have planet-encircling or global storms has been a challenge. The most recent Martian global dust storm occurred in 2007, significantly diminishing solar power available to two NASA Mars rovers then active halfway around the planet from each other -- Spirit and Opportunity. "The global dust storm in 2007 was the first major threat to the rovers since landing," said JPL's John Callas, project manager for Spirit and Opportunity. "We had to take special measures to enable their survival for several weeks with little sunlight to keep them powered. Each rover powered up only a few minutes each day, enough to warm them up, then shut down to the next day without even communicating with Earth. For many days during the worst of the storm, the rovers were completely on their own." Dust storms also will present challenges for astronauts on the Red Planet. Although the force of the wind on Mars is not as strong as portrayed in an early scene in the movie "The Martian," dust lofted during storms could affect electronics and health, as well as the availability of solar energy. The Red Planet has been observed shrouded by planet-encircling dust nine times since 1924, with the five most recent planetary storms detected in 1977, 1982, 1994, 2001 and 2007. The actual number of such events is no doubt higher. In some of the years when no orbiter was observing Mars up close, Mars was poorly positioned for Earth-based telescopic detection of dust storms during the Martian season when global storms are most likely. Shirley's 2015 paper in the journal Icarus reported finding a pattern in the occurrence of global dust storms when he factored in a variable linked to the orbital motion of Mars. Other planets have an effect on the momentum of Mars as it orbits the solar system's center of gravity. This effect on momentum varies with a cycle time of about 2.2 years, which is longer than the time it takes Mars to complete each orbit: about 1.9 years. The relationship between these two cycles changes constantly. Shirley found that global dust storms tend to occur when the momentum is increasing during the first part of the dust storm season. None of the global dust storms in the historic record occurred in years when the momentum was decreasing during the first part of the dust storm season. The paper noted that conditions in the current Mars dust-storm season are very similar to those for a number of years when global storms occurred in the past. Observations of the Martian atmosphere over the next few months will test whether the forecast is correct. Researchers at Malin Space Science Systems, in San Diego, post Mars weather reports each week based on observations using the Mars Color Imager camera on NASA's Mars Reconnaissance Orbiter. A series of local southern-hemisphere storms in late August grew into a major regional dust storm in early September, but subsided by mid-month without becoming global. Researchers will be closely watching to see what happens with the next regional storm. News Media Contact Guy Webster Jet Propulsion Laboratory, Pasadena, Calif. 818-354-6278 guy.webs...@jpl.nasa.gov Dwayne Brown / Laurie Cantillo NASA Headquarters, Washington 202-358-1726 / 202-358-1077 dwayne.c.br...@nasa.gov / laura.l.canti...@nasa.gov 2016-256 __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] NASA Flight Program Tests Mars Lander Vision System
http://www.jpl.nasa.gov/news/news.php?feature=6635 NASA Flight Program Tests Mars Lander Vision System Jet Propulsion Laboratory October 4, 2016 NASA tested new "eyes" for its next Mars rover mission on a rocket built by Masten Space Systems in Mojave, California, thanks in part to NASA's Flight Opportunities Program, or FOP. The agency's Jet Propulsion Laboratory in Pasadena, California, is leading development of the Mars 2020 rover and its Lander Vision System, or LVS. In 2014, the prototype vision system launched 1,066 feet (325 meters) into the air aboard Masten's rocket-powered "Xombie" test platform and helped guide the rocket to a precise landing at a predesignated target. LVS flew as part of a larger system of experimental landing technologies called the Autonomous Descent and Ascent Powered-flight Testbed, or ADAPT. LVS, a camera-based navigation system, photographs the terrain beneath a descending spacecraft and matches it with onboard maps allowing the craft to detect its location relative to landing hazards, such as boulders and outcroppings. The system can then direct the craft toward a safe landing at its primary target site or divert touchdown toward better terrain if there are hazards in the approaching target area. Image matching is aided by an inertial measurement unit that monitors orientation. The Flight Opportunities Program funded the Masten flight tests under the Space Technology Mission Directorate. The program obtains commercial suborbital space launch services to pursue science, technology and engineering to mature technology relevant to NASA's pursuit of space exploration. The program nurtures the emerging suborbital space industry and allows NASA to focus on deep space. Andrew Johnson, principal investigator in development of the Lander Vision System development, said the tests built confidence that the vision system will enable Mars 2020 to land safely. "By providing funding for flight tests, FOP motivated us to build guidance, navigation and control payloads for testing on Xombie," Johnson said. "In the end we showed a closed loop pinpoint landing demo that eliminated any technical concerns with flying the Lander Vision System on Mars 2020." According to "Lander Vision System for Safe and Precise Entry Descent and Landing," a 2012 abstract co-authored by Johnson for a Mars exploration workshop, LVS enables a broad range of potential landing sites for Mars missions. Typically, Mars landers have lacked the ability to analyze and react to hazards, the abstract says. To avoid hazards, mission planners selected wide-open landing sites with mostly flat terrain. As a result, landers and rovers were limited to areas with relatively limited geological features, and were unable to access many sites of high scientific interest with more complex and hazardous surface morphology. LVS will enable safe landing at these scientifically compelling Mars landing sites. An LVS-equipped mission allows for opportunities to land within more challenging environments and pursue new discoveries about Mars. With LVS baselined for inclusion on Mars 2020, the researchers are now focused on building the flight system ahead of its eventual role on the Red Planet. To learn more about NASA's flight opportunities program, visit: https://flightopportunities.nasa.gov/ To read more about NASA's Mars 2020 rover, visit: http://mars.nasa.gov/mars2020/ News Media Contact Leslie Williams NASA Armstrong Flight Research Center, Palmdale, Calif. 661-276-3893 leslie.a.willi...@nasa.gov Guy Webster Jet Propulsion Laboratory, Pasadena, Calif. 818-354-6278 guy.webs...@jpl.nasa.gov Gina Anderson NASA Headquarters, Washington 202-358-1160 gina.n.ander...@nasa.gov 2016-253 __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] NASA's Curiosity Rover Begins Next Mars Chapter
http://www.jpl.nasa.gov/news/news.php?feature=6632 NASA's Curiosity Rover Begins Next Mars Chapter Jet Propulsion Laboratory October 3, 2016 After collecting drilled rock powder in arguably the most scenic landscape yet visited by a Mars rover, NASA's Curiosity mobile laboratory is driving toward uphill destinations as part of its two-year mission extension that commenced Oct. 1. The destinations include a ridge capped with material rich in the iron-oxide mineral hematite, about a mile-and-a-half (two-and-a-half kilometers) ahead, and an exposure of clay-rich bedrock beyond that. These are key exploration sites on lower Mount Sharp, which is a layered, Mount-Rainier-size mound where Curiosity is investigating evidence of ancient, water-rich environments that contrast with the harsh, dry conditions on the surface of Mars today. "We continue to reach higher and younger layers on Mount Sharp," said Curiosity Project Scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory, Pasadena, California. "Even after four years of exploring near and on the mountain, it still has the potential to completely surprise us." Hundreds of photos Curiosity took in recent weeks amid a cluster of mesas and buttes of diverse shapes are fresh highlights among the more than 180,000 images the rover has taken since landing on Mars in August 2012. Newly available vistas include the rover's latest self-portrait from the color camera at the end of its arm and a scenic panorama from the color camera at the top of the mast. "Bidding good-bye to 'Murray Buttes,' Curiosity's assignment is the ongoing study of ancient habitability and the potential for life," said Curiosity Program Scientist Michael Meyer at NASA Headquarters, Washington. "This mission, as it explores the succession of rock layers, is reading the 'pages' of Martian history -- changing our understanding of Mars and how the planet has evolved. Curiosity has been and will be a cornerstone in our plans for future missions." The component images of the self-portrait were taken near the base of one of the Murray Buttes, at the same site where the rover used its drill on Sept. 18 to acquire a sample of rock powder. An attempt to drill at this site four days earlier had halted prematurely due to a short-circuit issue that Curiosity had experienced previously, but the second attempt successfully reached full depth and collected sample material. After departing the buttes area, Curiosity delivered some of the rock sample to its internal laboratory for analysis. This latest drill site -- the 14th for Curiosity -- is in a geological layer about 600 feet (180 meters) thick, called the Murray formation. Curiosity has climbed nearly half of this formation's thickness so far and found it consists primarily of mudstone, formed from mud that accumulated at the bottom of ancient lakes. The findings indicate that the lake environment was enduring, not fleeting. For roughly the first half of the new two-year mission extension, the rover team anticipates investigating the upper half of the Murray formation. "We will see whether that record of lakes continues further," Vasavada said. "The more vertical thickness we see, the longer the lakes were present, and the longer habitable conditions existed here. Did the ancient environment change over time? Will the type of evidence we've found so far transition to something else?" The "Hematite Unit" and "Clay Unit" above the Murray formation were identified from Mars orbiter observations before Curiosity's landing. Information about their composition, from the Compact Reconnaissance Imaging Spectrometer aboard NASA's Mars Reconnaissance Orbiter, made them high priorities as destinations for the rover mission. Both hematite and clay typically form in wet environments. Vasavada said, "The Hematite and the Clay units likely indicate different environments from the conditions recorded in older rock beneath them and different from each other. It will be interesting to see whether either or both were habitable environments." NASA approved Curiosity's second extended mission this summer on the basis of plans presented by the rover team. Additional extensions for exploring farther up Mount Sharp may be considered in the future. The Curiosity mission has already achieved its main goal of determining whether the landing region ever offered environmental conditions that would have been favorable for microbial life, if Mars has ever hosted life. The mission found evidence of ancient rivers and lakes, with a chemical energy source and all of the chemical ingredients necessary for life as we know it. The mission is also monitoring the modern environment of Mars, including natural radiation levels. Along with other robotic missions to the Red Planet, it is an important piece of NASA's Journey to Mars, leading toward human crew missions in the 2030s. JPL, a division of Caltech in Pasadena,
[meteorite-list] Extraterrestrial Impact Preceded Ancient Global Warming Event
http://news.rpi.edu/content/2016/10/13/extraterrestrial-impact-preceded-ancient-global-warming-event Extraterrestrial Impact Preceded Ancient Global Warming Event By Mary L. Martially Rensselaer Polytechnic Institute October 13, 2016 A comet strike may have triggered the Paleocene-Eocene Thermal Maximum (PETM), a rapid warming of the Earth caused by an accumulation of atmospheric carbon dioxide 56 million years ago, which offers analogs to global warming today. Sorting through samples of sediment from the time period, researchers at Rensselaer Polytechnic Institute discovered evidence of the strike in the form of microtektites - tiny dark glassy spheres typically formed by extraterrestrial impacts. The research will be published tomorrow in the journal Science. "This tells us that there was an extraterrestrial impact at the time this sediment was deposited - a space rock hit the planet," said Morgan Schaller, an assistant professor of earth and environmental sciences at Rensselaer, and corresponding author of the paper. "The coincidence of an impact with a major climate change is nothing short of remarkable." Schaller is joined in the research by Rensselaer professor Miriam Katz and graduate student Megan Fung, James Wright of Rutgers University, and Dennis Kent of Columbia University. Schaller was searching for fossilized remains of Foraminifera, a tiny organism that produces a shell, when he first noticed a microtektite in the sediment he was examining. Although it is common for researchers to search for fossilized remains in PETM sediments, microtektites have not been previously detected. Schaller and his team theorize this is because microtektites are typically dark in color, and do not stand out on the black sorting tray researchers use to search for light-colored fossilized remains. Once Schaller noticed the first microtektite, the researchers switched to a white sorting tray, and began to find more. At peak abundance, the research team found as many as three microtektites per gram of sediment examined. Microtektites are typically spherical, or tear-drop shaped, and are formed by an impact powerful enough to melt and vaporize the target area, casting molten ejecta into the atmosphere. Some microtektites from the samples contained "shocked quartz," definitive evidence of their impact origin, and exhibited microcraters or were sintered together, evidence of the speed at which they were traveling as they solidified and hit the ground. Atmospheric carbon dioxide increased rapidly during the PETM, and an accompanying spike in global temperatures of about 5 to 8 degrees Celsius lasted for about 150,000 years. Although this much is known, the source of the carbon dioxide had not been determined, and little is known about the exact sequence of events - such as how rapidly carbon dioxide entered the atmosphere, how quickly and at what rate temperatures began to rise, and how long it took to reach a global high temperature. One clue can be found in a sudden shift in the ratio of carbon isotopes (atoms containing a number of neutrons unequal to the protons in their nucleus) in certain fossils from the time period. In particular, Foraminifera, or "forams," produce a shell whose chemistry is representative of atmospheric and ocean carbon isotopes. The research team initially set out to examine the ratio of carbon isotopes in Foraminifera fossils over time, to more closely pinpoint events during the PETM. "In sediment records, when you look at the ratio of carbon-12 to carbon-13 in a particular species, you see that it's stable and then it abruptly shifts, wiggles back and forth and slowly returns to pre-event values over hundreds of thousands of years," Schaller said. "This evidence defines the event, and tells us that the atmosphere changed, in particular adding carbon from a source depleted in carbon-13. A comet impact on its own may have contributed carbon to the atmosphere, but is too small to explain the whole event and more likely acts as a trigger for additional carbon releases from other sources." As a source of fossils, the team used sediment cores - cylinders of sediment extracted vertically from sediment deposits with a hollow bit - known to correspond to the time period of the PETM. Sediments near the top are more recent, those further down are older, and signature layers indicating known events are used to calibrate the timescale represented in the sample. The team chose cores from three sites - Wilson Lake and Millville in New Jersey, and Blake Nose, an underwater site east of Florida - known for a rich sedimentary record of the time period. As Schaller tells it, the discovery of microtektites was "completely by accident." Ordinarily, the team passes samples through sieves of various sizes, to isolate samples most likely to contain forams. The tektites, which are smaller than most forams, would have been largely removed in
[meteorite-list] Chinese Meteorite Field Likely To Be World's Largest
http://gbtimes.com/china/chinese-meteorite-field-likely-be-worlds-largest Chinese meteorite field likely to be world's largest gbtimes October 14, 2016 Experts from the Chinese Academy of Sciences confirmed on October 13 that the meteorite-strewn field in Xinjiang Uyghur Autonomous Region is likely the world's largest. According to a report by Xinhua News Agency, the field of meteorites stretches to an estimated 425 kilometres, 150 kilometres larger than the Gibeon meteorite shower in Namibia. The shower has been named Altay, after the region in which it landed. First discovered in 1898, the 28-tonne Armanty meteorite was originally thought to be isolated, until the 430-kilogramme Ulasitai meteorite was discovered 100 years later. However, Shanghai Daily reports that it was not until 2011 that a third - the 5-tonne Wuxilike - was found that scientists noticed that all three were in a line stretched across 425 kilometres. "This suggests that the meteorites were all from the same parent asteroid before it separated as it entered the Earth's atmosphere," said Xu Weibiao, meteorite curator with the observatory under the Chinese Academy of Sciences. __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Annual Moon Impacts More Frequent Then Previously Estimated
hi, Paul... it's an interesting revelation that demonstrates the power of LRO's camera. but some of the write-ups are not getting it right (e.g. the New Scientist story claims "A new count of the moon’s craters has turned up 33 per cent more than predicted." sheesh!) if you want some context, including interviews with specialists beyond the press release, I recommend my S colleague Camille Carlisle's write-up here: https://is.gd/LxmxoZ clear skies, Kelly ** J. Kelly Beatty Senior Editor, Sky & Telescope F+W, A Content and eCommerce Company Sky & Telescope.com 617-864-7360 x22168 @NightSkyGuy -Original Message- From: Meteorite-list [mailto:meteorite-list-boun...@meteoritecentral.com] On Behalf Of Paul via Meteorite-list Sent: Thursday, October 13, 2016 9:29 PM To: Meteorite-list@meteoritecentral.com Subject: [meteorite-list] Annual Moon Impacts More Frequent Then Previously Estimated The moon has hundreds more craters than we thought Daily News, October 12, 2016 https://www.newscientist.com/article/2108929-the-moon-has-hundreds-more-craters-than-we-thought/ How old is our Moon? Hundreds of previously unseen craters could finally unlock its true age: New estimates suggest 180 craters of at least ten metres in diameter form each year by Liat Clark, Wired, A facelift for the Moon every 81,000 years, October 12, 2016 http://phys.org/news/2016-10-facelift-moon-years.html http://phys.org/news/2016-10-reveals-lunar-surface-features-younger.html The paper is: Speyerer, E. J., R. Z. Povilaitis, M. S. Robinson, P. C. Thomas, And R. V. Wagner, 2016, Quantifying crater production and regolith overturn on the Moon with temporal imaging. Nature. Vol. 538, pp. 215–218 (13 October 2016) doi:10.1038/nature19829 http://nature.com/articles/doi:10.1038/nature19829 Yours, Paul H. __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
[meteorite-list] Meteorite Picture of the Day
Today's Meteorite Picture of the Day: NWA 2824 TS Contributed by: Anne Black http://www.tucsonmeteorites.com/mpodmain.asp?DD=10/14/2016 __ Visit our Facebook page https://www.facebook.com/meteoritecentral and the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com https://pairlist3.pair.net/mailman/listinfo/meteorite-list
