[meteorite-list] Why Morocco Loves its Meteorites (And Meteorite News From Sudan)
Why Morocco loves its meteorites Why have more space rocks been recovered in Morocco than in other countries of a similar size? It’s a great question for the world’s Asteroid Day New Scientist, June 30, 2017 https://www.newscientist.com/article/2139323-why-morocco-loves-its-meteorites/ To save messages, an unrelated meteorite news article from Sudan is: Scientists collect fresh meteorites fallen in Sudan’s White Nile State Sudan Tribune, June 26, 2017 http://www.sudantribune.com/spip.php?article62834 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] The Day The Internet Stood Still
https://www.nasa.gov/specials/pathfinder20/ The Day The Internet Stood Still By Brian Dunbar July 2017 Twenty years ago, NASA landed a little rover on Mars . . . and blew up the Internet. As people clamored for pictures - overwhelming servers and bringing network traffic to a standstill - it became obvious that something fundamental had changed on how people expected to get information about NASA missions. NASA, through its Jet Propulsion Laboratory in California, had begun to release information online following Voyager's encounters with Uranus and Neptune in the 1980s. "When I arrived at JPL in 1985, I was already active in some of the online networks of the day such as CompuServe, so distributing pictures and information about NASA missions that way seemed natural," said former JPL public information manager Frank O'Donnell. "Also, Ron Baalke at JPL was very active posting information to Usenet, the Internet-based system of newsgroups. At the end of the '80s, I established a dialup bulletin board system at JPL, which members of the public could dial into directly to download pictures and text files." Then, in 1993, came the discovery of Comet Shoemaker-Levy 9, and astronomers' realization that it would hit Jupiter in July 1994. By then scientists were communicating by e-mail, transferring large files around the world and posting their work for discussion on the nascent World Wide Web. Now they were using those tools to plan worldwide campaign to observe the collision NASA's public affairs office followed suit, scheduling briefings throughout the encounter. (The comet had fragmented into numerous pieces that would arrive at Jupiter over several days.) The schedule published the time images were expected to be received and when they would be discussed on NASA TV. Naturally, Internet users started banging on NASA websites a few minutes before the pictures were scheduled to be downlinked, unable to wait until the scheduled release time. As Philip C. Plait wrote in "Bad Astronomy", ". . . the web nearly screeched to a halt due to the overwhelming amount of traffic as people tried to find pictures of the event from different observatories." The excitement wasn't limited to the public. Scientists found themselves doing their work live on NASA TV, as this clip from a National Geographic special shows. By coincidence it was also around this time that NASA's Office of Public Affairs announced that it would no longer mail news releases to reporters, but would instead distribute them online. Crowd-sourced Shoemaker-Levy made it clear to JPL they would have to prepare for something even bigger with Mars Pathfinder. Webmaster David Dubov told the New York Times shortly after the landing that he estimated the site would be receiving 25 million hits a day. (A "hit" is a request for information from one computer to another. On the web, a hit can represent the transfer of a picture, text or other page element. In the case of Pathfinder's deliberately stripped-down site, each web page comprised a few hits.) Dubov and JPL engineer Kirk Goodall would later revise that estimate to 60-80 million hits a day, traffic that would crash JPL's networks if the servers were hosted there. Goodall set out to build a network of mirror sites that could take the traffic off JPL's networks. Working with other U.S. science agencies, and ultimately corporations and Internet "backbone" providers, he did just that. (In other words, JPL crowd-sourced their solution a couple of decades before anyone knew crowdsourcing was a thing.) And the solution worked. The site took 30 million hits on landing day, July 4. On July 7, the first weekday after the landing, the site got 80 million hits. In comparison, the year before, the chess match between Gary Kasparov and IBM's Deep Blue computer peaked at 21 million hits, and the Atlanta Olympics website had topped out at 18 million hits on one day. Direct-to-Digital "One of the biggest changes with Mars Pathfinder was that it was the first mission that fully embraced the Internet as a primary way of getting out information to the public," said O'Donnell. "Before Pathfinder, the prevailing thinking was that eight-by-ten photo prints were the product needed for the public at large." It's worth remembering how the public got to see NASA images before the Internet era. NASA teams would review the raw images, select a few and distribute them as physical prints at news conferences. Media had to be in attendance at the conference to get a copy. Most newspapers and TV stations had to wait until a wire service had scanned the image and sent it out over their proprietary network. Most people might see a new image every day for a few days. A week later there might be a few more images published in weekly news magazines. Maybe six or eight months later, a magazine like National Geographic might publish a long story with a dozen or more
[meteorite-list] NASA Finds Evidence of Diverse Environments in Curiosity Samples
https://www.jpl.nasa.gov/news/news.php?feature=6870 NASA Finds Evidence of Diverse Environments in Curiosity Samples Jet Propulsion Laboratory June 9, 2017 NASA scientists have found a wide diversity of minerals in the initial samples of rocks collected by the Curiosity rover in the lowermost layers of Mount Sharp on Mars, suggesting that conditions changed in the water environments on the planet over time. Curiosity landed near Mount Sharp in Gale Crater in August 2012. It reached the base of the mountain in 2014. Layers of rocks at the base of Mount Sharp accumulated as sediment within ancient lakes around 3.5 billion years ago. Orbital infrared spectroscopy had shown that the mountain's lowermost layers have variations in minerals that suggest changes in the area have occurred. In a paper published recently in Earth and Planetary Science Letters, scientists in the Astromaterials Research and Exploration Science (ARES) Division at NASA's Johnson Space Center in Houston report on the first four samples collected from the lower layers of Mount Sharp. "We went to Gale Crater to investigate these lower layers of Mount Sharp that have these minerals that precipitated from water and suggest different environments," said Elizabeth Rampe, the first author of the study and a NASA exploration mission scientist at Johnson. "These layers were deposited about 3.5 billion years ago, coinciding with a time on Earth when life was beginning to take hold. We think early Mars may have been similar to early Earth, and so these environments might have been habitable." The minerals found in the four samples drilled near the base of Mount Sharp suggest several different environments were present in ancient Gale Crater. There is evidence for waters with different pH and variably oxidizing conditions. The minerals also show that there were multiple source regions for the rocks in "Pahrump Hills" and "Marias Pass." The paper primarily reports on three samples from the Pahrump Hills region. This is an outcrop at the base of Mount Sharp that contains sedimentary rocks scientists believe formed in the presence of water. The other sample, called "Buckskin," was reported last year, but those data are incorporated into the paper. Studying such rock layers can yield information about Mars' past habitability, and determining minerals found in the layers of sedimentary rock yields much data about the environment in which they formed. Data collected at Mount Sharp with the Chemistry and Mineralogy (CheMin) instrument on Curiosity showed a wide diversity of minerals. At the base are minerals from a primitive magma source; they are rich in iron and magnesium, similar to basalts in Hawaii. Moving higher in the section, scientists saw more silica-rich minerals. In the "Telegraph Peak" sample, scientists found minerals similar to quartz. In the "Buckskin" sample, scientists found tridymite. Tridymite is found on Earth, for example, in rocks that formed from partial melting of Earth's crust or in the continental crust -- a strange finding because Mars never had plate tectonics. In the "Confidence Hills" and "Mojave 2" samples, scientists found clay minerals, which generally form in the presence of liquid water with a near-neutral pH, and therefore could be good indicators of past environments that were conducive to life. The other mineral discovered here was jarosite, a salt that forms in acidic solutions. The jarosite finding indicates that there were acidic fluids at some point in time in this region. There are different iron-oxide minerals in the samples as well. Hematite was found near the base; only magnetite was found at the top. Hematite contains oxidized iron, whereas magnetite contains both oxidized and reduced forms of iron. The type of iron-oxide mineral present may tell scientists about the oxidation potential of the ancient waters. The authors discuss two hypotheses to explain this mineralogical diversity. The lake waters themselves at the base were oxidizing, so either there was more oxygen in the atmosphere or other factors encouraged oxidation. Another hypothesis -- the one put forward in the paper -- is that later-stage fluids arose. After the rock sediments were deposited, some acidic, oxidizing groundwater moved into the area, leading to precipitation of the jarosite and hematite. In this scenario, the environmental conditions present in the lake and in later groundwater were quite different, but both offered liquid water and a chemical diversity that could have been exploited by microbial life. "We have all this evidence that Mars was once really wet but now is dry and cold," Rampe said. "Today, much of the water is locked up in the poles and in the ground at high latitudes as ice. We think that the rocks Curiosity has studied reveal ancient environmental changes that occurred as Mars started to lose its atmosphere and water was lost to space." In the
[meteorite-list] NASA's Asteroid-Hunting Spacecraft a Discovery Machine (NEOWISE)
https://www.jpl.nasa.gov/news/news.php?feature=6864 NASA's Asteroid-Hunting Spacecraft a Discovery Machine Jet Propulsion Laboratory June 5, 2017 NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission has released its third year of survey data, with the spacecraft discovering 97 previously unknown celestial objects in the last year. Of those, 28 were near-Earth objects, 64 were main belt asteroids and five were comets. The spacecraft has now characterized a total of 693 near-Earth objects since the mission was re-started in December 2013. Of these, 114 are new. The NEOWISE team has released an animation depicting this solar system survey's discoveries and characterizations for its third year of operations. "NEOWISE is not only discovering previously uncharted asteroids and comets, but it is providing excellent data on many of those already in our catalog," said Amy Mainzer, NEOWISE principal investigator from NASA's Jet Propulsion Laboratory in Pasadena, California. "It is also proving to be an invaluable tool in in the refining and perfecting of techniques for near-Earth object discovery and characterization by a space-based infrared observatory." Near-Earth objects (NEOs) are comets and asteroids that have been nudged by the gravitational attraction of the planets in our solar system into orbits that allow them to enter Earth's neighborhood. Ten of the objects discovered by NEOWISE in the past year have been classified as potentially hazardous asteroids, based on their size and their orbits. More than 2.6 million infrared images of the sky were collected in the third year of operations by NEOWISE. These data are combined with the Year 1 and 2 NEOWISE data into a single archive that contains approximately 7.7 million sets of images and a database of more than 57.7 billion source detections extracted from those images. The NEOWISE images also contain glimpses of rare objects, like comet C/2010 L5 WISE. A new technique of modeling comet behavior called tail-fitting showed that this particular comet experienced a brief outburst as it swept through the inner-solar system. "Comets that have abrupt outbursts are not commonly found, but this may be due more to the sudden nature of the activity rather than their inherent rarity," said Emily Kramer, a NASA Postdoctoral Program Fellow at JPL and lead author of paper on the NEOWISE study. "It is great for astronomers to view and collect cometary data when they find an outburst, but since the activity is so short-lived, we may simply miss them most of the time." The tail-fitting technique identifies the size and quantity of dust particles in the vicinity of the comet, and when they were ejected from the comet's nucleus, revealing the history of the comet's activity. With tail-fitting, future all-sky surveys may be able to find and collect data on more cometary outburst activity when it happens. A paper detailing the tail-fitting technique and other results of the study was published in the March 20 volume of the Astrophysical Journal. Originally called the Wide-field Infrared Survey Explorer (WISE), the spacecraft was launched in December 2009. It was placed in hibernation in 2011 after its primary astrophysics mission was completed. In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission: to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects. NEOWISE also is characterizing more distant populations of asteroids and comets to provide information about their sizes and compositions. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the NEOWISE mission for NASA's Planetary Defense Coordination Office within the Science Mission Directorate in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at Caltech in Pasadena. Caltech manages JPL for NASA. To review the latest data release from NEOWISE please visit: http://wise2.ipac.caltech.edu/docs/release/neowise/ For more information about NEOWISE, visit: https://www.nasa.gov/neowise and http://neowise.ipac.caltech.edu/ More information about asteroids and near-Earth objects is at: https://www.jpl.nasa.gov/asteroidwatch News Media Contact DC Agle Jet Propulsion Laboratory, Pasadena, Calif. 818-393-9011 a...@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 2017-159 __ 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
[meteorite-list] Curiosity Peels Back Layers on Ancient Martian Lake
https://www.jpl.nasa.gov/news/news.php?feature=6863 Curiosity Peels Back Layers on Ancient Martian Lake Jet Propulsion Laboratory June 1, 2017 Fast Facts: o NASA's Curiosity Mars rover mission has provided an unprecedented level of detail about an ancient lake environment on Mars that offered favorable conditions for microbial life. o A lake in Mars' Gale Crater long ago was stratified, with oxidant-rich shallows and oxidant-poor depths. o The lake offered multiple types of microbe-friendly environments simultaneously. A long-lasting lake on ancient Mars provided stable environmental conditions that differed significantly from one part of the lake to another, according to a comprehensive look at findings from the first three-and-a-half years of NASA's Curiosity rover mission. Different conditions favorable for different types of microbes existed simultaneously in the same lake. Previous work had revealed the presence of a lake more than three billion years ago in Mars' Gale Crater. This study defines the chemical conditions that existed in the lake and uses Curiosity's powerful payload to determine that the lake was stratified. Stratified bodies of water exhibit sharp chemical or physical differences between deep water and shallow water. In Gale's lake, the shallow water was richer in oxidants than deeper water was. "These were very different, co-existing environments in the same lake," said Joel Hurowitz of Stony Brook University, Stony Brook, New York, lead author of a report of the findings in the June 2 edition of the journal Science. "This type of oxidant stratification is a common feature of lakes on Earth, and now we've found it on Mars. The diversity of environments in this Martian lake would have provided multiple opportunities for different types of microbes to survive, including those that thrive in oxidant-rich conditions, those that thrive in oxidant-poor conditions, and those that inhabit the interface between those settings." Whether Mars has ever hosted any life is still unknown, but seeking signs of life on any planet -- whether Earth, Mars or more-distant icy worlds -- begins with reconstruction of the environment to determine if it was capable of supporting life. Curiosity's primary goal when it landed inside Gale Crater in 2012 was to determine whether Mars has ever offered environmental conditions favorable for microbial life. In its first year, on the crater floor at "Yellowknife Bay," the rover found evidence of ancient freshwater river and lake environments with all the main chemical ingredients for life and a possible energy source for life. Curiosity has since driven to the base of Mount Sharp, a layered mountain inside the crater, and inspected rock layers that grow progressively younger as the rover gains elevation on lower Mount Sharp. Differences in the physical, chemical and mineral characteristics of several sites on lower Mount Sharp at first presented a puzzle to the rover team. For example, some rocks showed thicker layering with a larger proportion of an iron mineral called hematite, while other rocks showed very fine layers and more of an iron mineral called magnetite. Comparing these properties suggested very distinctive environments of deposition. Researchers considered whether these differences could have resulted from environmental conditions fluctuating over time or differing from place to place. "We could tell something was going on," Hurowitz said. "What was causing iron minerals to be one flavor in one part of the lake and another flavor in another part of the lake? We had an 'Aha!' moment when we realized that the mineral information and the bedding-thickness information mapped perfectly onto each other in a way you would expect from a stratified lake with a chemical boundary between shallow water and deeper water." In addition to revealing new information about chemical conditions within the lake, the report by Hurowitz and 22 co-authors also documents fluctuations in the climate of ancient Mars. One such change happened between the time crater-floor rocks were deposited and the time the rocks that now make up the base of Mount Sharp were deposited. Those later rocks are exposed at "Pahrump Hills" and elsewhere. The method the team used for detecting changes in ancient climate conditions on Mars resembles how ice cores are used to study past temperature conditions on Earth. It is based on comparing differences in the chemical composition of layers of mud-rich sedimentary rock that were deposited in quiet waters in the lake. While the lake was present in Gale, climate conditions changed from colder and drier to warmer and wetter. Such short-term fluctuations in climate took place within a longer-term climate evolution from the ancient warmer and wetter conditions that supported lakes, to today's arid Mars. "These results give us unprecedented detail in answering questions about
[meteorite-list] Cassini Finds Saturn Moon Enceladus May Have Tipped Over
https://www.jpl.nasa.gov/news/news.php?feature=6860 Cassini Finds Saturn Moon May Have Tipped Over Jet Propulsion Laboratory May 30, 2017 Saturn's icy, ocean-bearing moon Enceladus may have tipped over in the distant past, according to recent research from NASA's Cassini mission. Researchers with the mission found evidence that the moon's spin axis -- the line through the north and south poles -- has reoriented, possibly due to a collision with a smaller body, such as an asteroid. Examining the moon's features, the team showed that Enceladus appears to have tipped away from its original axis by about 55 degrees -- more than halfway toward rolling completely onto its side. "We found a chain of low areas, or basins, that trace a belt across the moon's surface that we believe are the fossil remnants of an earlier, previous equator and poles," said Radwan Tajeddine, a Cassini imaging team associate at Cornell University, Ithaca, New York, and lead author of the paper. The area around the icy moon's current south pole is a geologically active region where long, linear fractures referred to as tiger stripes slice across the surface. Tajeddine and colleagues speculate that an asteroid may have struck the region in the past when it was closer to the equator. "The geological activity in this terrain is unlikely to have been initiated by internal processes," he said. "We think that, in order to drive such a large reorientation of the moon, it's possible that an impact was behind the formation of this anomalous terrain." In 2005, Cassini discovered that jets of water vapor and icy particles spray from the tiger stripe fractures -- evidence that an underground ocean is venting directly into space from beneath the active south polar terrain. Whether it was caused by an impact or some other process, Tajeddine and colleagues think the disruption and creation of the tiger-stripe terrain caused some of Enceladus' mass to be redistributed, making the moon's rotation unsteady and wobbly. The rotation would have eventually stabilized, likely taking more than a million years. By the time the rotation settled down, the north-south axis would have reoriented to pass through different points on the surface -- a mechanism researchers call "true polar wander." The polar wander idea helps to explain why Enceladus' modern-day north and south poles appear quite different. The south is active and geologically young, while the north is covered in craters and appears much older. The moon's original poles would have looked more alike before the event that caused Enceladus to tip over and relocate the disrupted tiger-stripe terrain to the moon's south polar region. The results were published in the online edition of the journal Icarus on April 30, 2017. The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the mission for NASA's Science Mission Directorate, Washington. JPL designed, developed and assembled the Cassini orbiter. More information about Cassini: https://www.nasa.gov/cassini https://saturn.jpl.nasa.gov News Media Contact Preston Dyches Jet Propulsion Laboratory, Pasadena, Calif. 818-394-7013 preston.dyc...@jpl.nasa.gov 2017-155 __ 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] High-Silica 'Halos' Shed Light on Wet Ancient Mars
https://www.jpl.nasa.gov/news/news.php?feature=6859 High-Silica 'Halos' Shed Light on Wet Ancient Mars Jet Propulsion Laboratory May 30, 2017 Pale "halos" around fractures in bedrock analyzed by NASA's Curiosity Mars rover contain copious silica, indicating that ancient Mars had liquid water for a long time. "The concentration of silica is very high at the centerlines of these halos," said Jens Frydenvang, a rover-team scientist at Los Alamos National Laboratory in New Mexico, and the University of Copenhagen in Denmark. "What we're seeing is that silica appears to have migrated between very old sedimentary bedrock and into younger overlying rocks." Frydenvang is the lead author of a report about these findings published in Geophysical Research Letters. NASA landed Curiosity on Mars in 2012 with a goal to determine whether Mars ever offered environmental conditions favorable for microbial life. The mission "has been very successful in showing that Gale Crater once held a lake with water that we would even have been able to drink from, but we still don't know how long this habitable environment endured," he said. "What this finding tells us is that, even when the lake eventually evaporated, substantial amounts of groundwater were present for longer than we previously thought -- further expanding the window for when life might have existed on Mars." For more information about the newly published report, visit: http://bit.ly/2r8dyOF The halos were first analyzed in 2015 with Curiosity's science-instrument payload, including the laser-shooting Chemistry and Camera (ChemCam) instrument, which was developed at Los Alamos National Laboratory in conjunction with the French space agency. The rover has subsequently explored higher and younger layers of lower Mount Sharp, investigating how ancient environmental conditions changed. NASA's two active Mars rovers and three Mars orbiters are all part of ambitious robotic exploration to understand Mars, which helps lead the way for sending humans to Mars in the 2030s. The Curiosity mission is managed by NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, for NASA's Science Mission Directorate, Washington. For more about Curiosity, visit: http://www.nasa.gov/curiosity News Media Contact Guy Webster Jet Propulsion Laboratory, Pasadena, Calif. 818-354-6278 guy.webs...@jpl.nasa.gov Laura Mullane Los Alamos National Laboratory, Los Alamos, N.M. 505-667-6012 mull...@lanl.gov Laurie Cantillo / Dwayne Brown NASA Headquarters, Washington 202-358-1077 / 202-358-1726 laura.l.canti...@nasa.gov / dwayne.c.br...@nasa.gov 2017-154 __ 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] AD: Tunguska Wood Specimens Available For Sale (Ad 13/14)
Dear Fellow Collectors, Hope you are all doing well. Recently updated my website to include two very nice specimens from the University of Bologna Expedition to the site of the Tunguska Event. A wood section showing the “light rings” studied on that expedition, within the tree rings in the specimen, and a bark specimen available at below retail price. Additionally, I have lowered some prices of a few specimens listed, particularly a large full slice of Sikhote Alin that is expertly etched, and available at an absolute bargain now. As always there are an abundance of other specimens available on my site, such as specimens of meteorite falls, classified and unclassified NWAs, the very last available specimen of Minnesota’s High Island Creek iron, and various specimens of impact breccias. Please take a moment from your busy day to consider adding some specimens to your collection. Link: https://bigjohnmeteorites.com Hope you have a great weekend ahead of you! Cheers! John A. Shea, MD IMCA 3295 __ 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 11359 Contributed by: Mohamed Salem EL Wali El Alaoui http://www.tucsonmeteorites.com/mpodmain.asp?DD=07/07/2017 __ 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
