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Mon Feb 6 22:56:05 CST 2017

Good morning all,
 Hope you had a great weekend and your week is going well..last week was one of the most amazing I have experienced in the time I have been visiting schools ..it was way fun and in some ways mind boggling... an amazing  adventure... between all the driving,...1800 miles (3,000 kilometers), 22 presentations, about 3,000 students …running from school to school…it was awesome but no one will ever understand how crazy it is to live it…:-) .at times I felt like I was in some kind of time warp…I can only describe it as so much fun…I wouldn’t want to do it any other way….this week I will be in Tampa at Chiles Elem; Hunter’s Green Elem; Clark Elem; and Turner/Bartels Elementary schools. It never gets old and it is my favorite thing to do….the kids are awesome and the teachers, my heroes, are so very helpful…. wishing you a wonderful day...we have to remember to always do our best, enjoy everything we do, live in the present, make each day special, be appreciative of the good in our lives, smile & have fun!!!! …:-) :-)  gabe

NASA's Curiosity Rover Sharpens Paradox of Ancient Mars
 <https://www.nasa.gov/sites/default/files/thumbnails/image/pia17595-full.jpg>
Bedrock at this site added to a puzzle about ancient Mars by indicating that a lake was present, but that little carbon dioxide was in the air to help keep a lake unfrozen.
Credits: NASA/JPL-Caltech/MSSS
Full image and caption <https://www.nasa.gov/content/yellowknife-bay-formation-on-mars>
Mars scientists are wrestling with a problem. Ample evidence says ancient Mars was sometimes wet, with water flowing and pooling on the planet’s surface. Yet, the ancient sun was about one-third less warm and climate modelers struggle to produce scenarios that get the surface of Mars warm enough for keeping water unfrozen.  A leading theory is to have a thicker carbon-dioxide atmosphere forming a greenhouse-gas blanket, helping to warm the surface of ancient Mars. However, according to a new analysis of data from NASA's Mars rover Curiosity, Mars had far too little carbon dioxide about 3.5 billion years ago to provide enough greenhouse-effect warming to thaw water ice. The same Martian bedrock in which Curiosity found sediments from an ancient lake where microbes could have thrived is the source of the evidence adding to the quandary about how such a lake could have existed. Curiosity detected no carbonate minerals in the samples of the bedrock it analyzed. The new analysis concludes that the dearth of carbonates in that bedrock means Mars' atmosphere when the lake existed -- about 3.5 billion years ago -- could not have held much carbon dioxide. "We've been particularly struck with the absence of carbonate minerals in sedimentary rock the rover has examined," said Thomas Bristow of NASA's Ames Research Center, Moffett Field, California. "It would be really hard to get liquid water even if there were a hundred times more carbon dioxide in the atmosphere than what the mineral evidence in the rock tells us." Bristow is the principal investigator for the Chemistry and Mineralogy (CheMin) instrument on Curiosity and lead author of the study being published this week in the Proceedings of the National Academy of Science. Curiosity has made no definitive detection of carbonates in any lakebed rocks sampled since it landed in Gale Crater in 2011. CheMin can identify carbonate if it makes up just a few percent of the rock. The new analysis by Bristow and 13 co-authors calculates the maximum amount of carbon dioxide that could have been present, consistent with that dearth of carbonate. In water, carbon dioxide combines with positively charged ions such as magnesium and ferrous iron to form carbonate minerals. Other minerals in the same rocks indicate those ions were readily available. The other minerals, such as magnetite and clay minerals, also provide evidence that subsequent conditions never became so acidic that carbonates would have dissolved away, as they can in acidic groundwater. The dilemma has been building for years: Evidence about factors that affect surface temperatures -- mainly the energy received from the young sun and the blanketing provided by the planet's atmosphere -- adds up to a mismatch with widespread evidence for river networks and lakes on ancient Mars. Clues such as isotope ratios in today's Martian atmosphere indicate the planet once held a much denser atmosphere than it does now. Yet theoretical models of the ancient Martian climate struggle to produce conditions that would allow liquid water on the Martian surface for many millions of years. One successful model proposes a thick carbon-dioxide atmosphere that also contains molecular hydrogen. How such an atmosphere would be generated and sustained, however, is controversial. The new study pins the puzzle to a particular place and time, with an on-the-ground check for carbonates in exactly the same sediments that hold the record of a lake about a billion years after the planet formed. For the past two decades, researchers have used spectrometers on Mars orbiters to search for carbonate that could have resulted from an early era of more abundant carbon dioxide. They have found far less than anticipated.   "It's been a mystery why there hasn't been much carbonate seen from orbit," Bristow said. "You could get out of the quandary by saying the carbonates may still be there, but we just can't see them from orbit because they're covered by dust, or buried, or we're not looking in the right place. The Curiosity results bring the paradox to a focus. This is the first time we've checked for carbonates on the ground in a rock we know formed from sediments deposited under water.” The new analysis concludes that no more than a few tens of millibars of carbon dioxide could have been present when the lake existed, or it would have produced enough carbonate for Curiosity's CheMin to detect it. A millibar is one one-thousandth of sea-level air pressure on Earth. The current atmosphere of Mars is less than 10 millibars and about 95 percent carbon dioxide. "This analysis fits with many theoretical studies that the surface of Mars, even that long ago, was not warm enough for water to be liquid," said Robert Haberle, a Mars-climate scientist at NASA Ames and a co-author of the paper. "It's really a puzzle to me.” Researchers are evaluating multiple ideas for how to reconcile the dilemma.  "Some think perhaps the lake wasn't an open body of liquid water. Maybe it was liquid covered with ice," Haberle said. "You could still get some sediments through to accumulate in the lakebed if the ice weren't too thick.” A drawback to that explanation is that the rover team has sought and not found in Gale Crater evidence that would be expected from ice-covered lakes, such as large and deep cracks called ice wedges, or "dropstones," which become embedded in soft lakebed sediments when they penetrate thinning ice. If the lakes were not frozen, the puzzle is made more challenging by the new analysis of what the lack of a carbonate detection by Curiosity implies about the ancient Martian atmosphere. "Curiosity's traverse through streambeds, deltas, and hundreds of vertical feet of mud deposited in ancient lakes calls out for a vigorous hydrological system supplying the water and sediment to create the rocks we're finding," said Curiosity Project Scientist Ashwin Vasavada of NASA's Jet Propulsion Laboratory, Pasadena, California. "Carbon dioxide, mixed with other gases like hydrogen, has been the leading candidate for the warming influence needed for such a system. This surprising result would seem to take it out of the running.” When two lines of scientific evidence appear irreconcilable, the scene may be set for an advance in understanding why they are not. The Curiosity mission is continuing to investigate ancient environmental conditions on Mars. It is managed by JPL, a division of Caltech in Pasadena, for NASA's Science Mission Directorate, Washington. Curiosity and other Mars science missions are a key part of NASA's Journey to Mars, building on decades of robotic exploration to send humans to the Red Planet in the 2030s. For more about Curiosity, visit: http://www.nasa.gov/curiosity <http://www.nasa.gov/curiosity> Learn about NASA's Journey to Mars at: http://www.nasa.gov/journeytomars <http://www.nasa.gov/journeytomars>

Black Hole Meal Sets Record for Duration And Size
 <https://www.nasa.gov/sites/default/files/thumbnails/image/tidal.jpg>
Artist’s illustration depicts what astronomers call a “tidal disruption event,” or TDE.
Credits: Illustration: CXC/M. Weiss; X-ray: NASA/CXC/UNH/D. Lin et al, Optical: CFHT

A giant black hole ripped apart a star and then gorged on its remains for about a decade, according to astronomers. This is more than ten times longer than any observed episode of a star’s death by black hole. Researchers made this discovery using data from NASA’s Chandra X-ray Observatory and Swift satellite as well as ESA’s XMM-Newton. The trio of orbiting X-ray telescopes found evidence for a “tidal disruption event” (TDE), wherein the tidal forces due to the intense gravity from a black hole can destroy an object – such as a star – that wanders too close. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inwards to be ingested by the black hole, the material heats up to millions of degrees and generates a distinct X-ray flare. “We have witnessed a star’s spectacular and prolonged demise,” said Dacheng Lin from the University of New Hampshire in Durham, New Hampshire, who led the study. “Dozens of tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one.” The extraordinary long bright phase of this event spanning over ten years means that among observed TDEs this was either the most massive star ever to be completely torn apart during one of these events, or the first where a smaller star was completely torn apart. The X-ray source containing this force-fed black hole, known by its abbreviated name of XJ1500+0154, is located in a small galaxy about 1.8 billion light years from Earth. The source was not detected in a Chandra observation on April 2nd, 2005, but was detected in an XMM-Newton observation on July 23rd, 2005, and reached peak brightness in a Chandra observation on June 5, 2008. These observations show that the source became at least 100 times brighter in X-rays. Since then, Chandra, Swift, and XMM-Newton have observed it multiple times. The sharp X-ray vision of Chandra data shows that XJ1500+0154 is located at the center of its host galaxy, the expected location for a supermassive black hole. The X-ray data also indicate that radiation from material surrounding this black hole has consistently surpassed the so-called Eddington limit, defined by a balance between the outward pressure of radiation from the hot gas and the inward pull of the gravity of the black hole.  “For most of the time we’ve been looking at this object, it has been growing rapidly,” said co-author James Guillochon of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “This tells us something unusual – like a star twice as heavy as our Sun – is being fed into the black hole.” The conclusion that supermassive black holes can grow, from TDEs and perhaps other means, at rates above those corresponding to the Eddington limit has important implications. Such rapid growth may help explain how supermassive black holes were able to reach masses about a billion times higher than the sun when the universe was only about a billion years old. “This event shows that black holes really can grow at extraordinarily high rates,” said co-author Stefanie Komossa of QianNan Normal University for Nationalities in Duyun City, China. “This may help understand how precocious black holes came to be.” Based on the modeling by the researchers the black hole’s feeding supply should be significantly reduced in the next decade. This would result in XJ1500+0154 fading in X-ray brightness over the next several years. A paper describing these results appears on February 6th issue in Nature Astronomy and is available online <https://arxiv.org/abs/1702.00792>. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations. Read More from NASA's Chandra X-ray Observatory <http://chandra.harvard.edu/photo/2017/tidal/>. For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra <http://www.nasa.gov/chandra>

Jupiter Polar Haze in False Color
 <https://www.nasa.gov/sites/default/files/thumbnails/image/pia21379-1041.jpg>
This false color view of Jupiter’s polar haze was created by citizen scientist Gerald Eichstädt using data from the JunoCam instrument on NASA’s Juno spacecraft. The image was taken on Dec. 11, 2016 at 2:30 p.m. PST (5:30 p.m. EST), when the spacecraft was 285,000 miles (459,000 kilometers) from Jupiter on the outbound leg of its third close flyby. This image is composited from four images taken through different filters: red, green, blue and methane. When the near-infrared methane image is processed with the others, the result is a false color product that highlights high clouds and high altitude hazes. The Great Red Spot and Oval BA (just below the Great Red Spot) are high in Jupiter’s atmosphere, thus bright in this picture.  The high-altitude haze layer over the south pole partially obscures our view of the storms below. By combining the methane data with the visible light images, we can learn about the vertical structure of Jupiter’s atmosphere.  JunoCam's raw images are available at www.missionjuno.swri.edu/junocam <http://www.missionjuno.swri.edu/junocam> for the public to peruse, download and process into image products. JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. Juno is part of NASA's New Frontiers Program, which is managed at NASA's Marshall Space Flight Center in Huntsville, Alabama, for NASA's Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. Caltech in Pasadena, California, manages JPL for NASA. More information about Juno is online at http://www.nasa.gov/juno <http://www.nasa.gov/juno> and http://missionjuno.swri.edu <http://missionjuno.swri.edu/>.

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