archive-edu.com » EDU » U » USRA.EDU

Total: 1151

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • Cassini Watches Storm Choke on Its Own Tail
    The storm first detected on December 5 2010 and tracked by Cassini s radio and plasma wave subsystem and imaging cameras erupted around 33 N latitude Shortly after the bright turbulent head of the storm emerged and started moving west it spawned a clockwise spinning vortex that drifted much more slowly Within months the storm wrapped around the planet at that latitude stretching about 190 000 miles 300 000 kilometers in circumference thundering and throwing lightning along the way Terrestrial storms have never run into their own wakes they encounter topographic features like mountains first and expend themselves But Saturn has no land to stop its hurricanes The bright turbulent storm head was able to chomp all the way around the planet It was only when the head of the storm ran into the vortex in June 2011 that the massive convective storm faded away Why the encounter would shut down the storm is still a mystery By August 28 after 267 days the Saturn storm stopped thundering for good While Cassini s infrared detectors continue to track some lingering effects in higher layers of Saturn s atmosphere the troposphere which is the weather producing layer lower in the atmosphere has been quiet at that latitude This thunder and lightning storm on Saturn was a beast said Kunio Sayanagi the paper s lead author and a Cassini imaging team associate at Hampton University in Virginia The storm maintained its intensity for an unusually long time The storm head itself thrashed for 201 days and its updraft erupted with an intensity that would have sucked out the entire volume of Earth s atmosphere in 150 days And it also created the largest vortex ever observed in the troposphere of Saturn expanding up to 7500 miles 12 000 kilometers across The vortex

    Original URL path: http://www.lpi.usra.edu/features/cassini/020713/ (2016-02-15)
    Open archived version from archive


  • Herschel Finds Star Past Its Prime Possibly Making Planets
    this star said Edwin Bergin of the University of Michigan in Ann Arbor Bergin led the new study appearing in the journal Nature Typically stars of this age have cleared out their surrounding material but this star still has enough mass to make the equivalent of 50 Jupiters Bergin said In addition to revealing the peculiar state of the star the findings also demonstrate a new more precise method for weighing planet forming disks Previous techniques for assessing the mass were indirect and uncertain The new method can directly probe the gas that typically goes into making planets Planets are born out of material swirling around young stars and the mass of this material is a key factor controlling their formation Astronomers did not know before the new study whether the disk around TW Hydrae contained enough material to form new planets similar to our own Before we had to use a proxy to guess the gas quantity in the planet forming disks said Paul Goldsmith the NASA project scientist for Herschel at NASA s Jet Propulsion Laboratory in Pasadena California This is another example of Herschel s versatility and sensitivity yielding important new results about star and planet formation Using Herschel scientists were able to take a fresh look at the disk with the space telescope to analyze light coming from TW Hydrae and pick out the spectral signature of a gas called hydrogen deuteride Simple hydrogen molecules are the main gas component of planets but they emit light at wavelengths too short to be detected by Herschel Gas molecules containing deuterium a heavier version of hydrogen emit light at longer far infrared wavelengths that Herschel is equipped to see This enabled astronomers to measure the levels of hydrogen deuteride and obtain the weight of the disk with the

    Original URL path: http://www.lpi.usra.edu/features/herschel/020713/ (2016-02-15)
    Open archived version from archive

  • NASA Officially Joins ESA’s “Dark Universe” Mission
    the Sun and Earth in this case precisely equals the force required for a small object such as the Euclid spacecraft to maintain a relatively stationary position behind Earth as seen from the Sun NASA is very proud to contribute to ESA s mission to understand one of the greatest science mysteries of our time said John Grunsfeld associate administrator for NASA s Science Mission Directorate at the agency s Headquarters in Washington NASA and ESA recently signed an agreement outlining NASA s role in the project NASA will contribute 16 state of the art infrared detectors and four spare detectors for one of two science instruments planned for Euclid ESA s Euclid mission is designed to probe one of the most fundamental questions in modern cosmology and we welcome NASA s contribution to this important endeavor the most recent in a long history of cooperation in space science between our two agencies said Alvaro Giménez ESA s Director of Science and Robotic Exploration In addition NASA has nominated three U S science teams totaling 40 new members for the Euclid Consortium This is in addition to 14 U S scientists already supporting the mission The Euclid Consortium is an international body of 1000 members who will oversee development of the instruments manage science operations and analyze data Euclid will map the dark matter in the universe Matter as we know it the atoms that make up the human body for example is a fraction of the total matter in the universe The rest about 85 is dark matter consisting of particles of an unknown type Dark matter first was postulated in 1932 but still has not been detected directly It is called dark matter because it does not interact with light Dark matter interacts with ordinary matter through gravity

    Original URL path: http://www.lpi.usra.edu/features/esa/012513/ (2016-02-15)
    Open archived version from archive

  • Titan Gets a Dune “Makeover”
    rain to erode its surface We found that craters on Titan were on average hundreds of yards meters shallower than similarly sized craters on Ganymede suggesting that some process on Titan is filling its craters says Neish who is lead author of a paper about this research published online in Icarus on December 3 2012 The team used the average depth versus diameter trend for craters on Ganymede derived from stereo images from NASA s Galileo spacecraft The same trend for craters on Titan was calculated using estimates of the crater depth from images made by Cassini s radar instrument Titan s atmosphere is mostly nitrogen with a trace of methane and other more complex molecules made of hydrogen and carbon hydrocarbons The source of Titan s methane remains a mystery because methane in the atmosphere is broken down over relatively short timescales by sunlight Fragments of methane molecules then recombine into more complex hydrocarbons in the upper atmosphere forming a thick orange smog that hides the surface from view Some of the larger particles eventually rain out onto the surface where they appear to get bound together to form the sand Since the sand appears to be produced from the atmospheric methane Titan must have had methane in its atmosphere for at least several hundred million years in order to fill craters to the levels we are seeing says Neish However researchers estimate Titan s current supply of methane should be broken down by sunlight within tens of millions of years so Titan either had a lot more methane in the past or it is being replenished somehow Team members say it s possible that other processes could be filling the craters on Titan erosion from the flow of liquid methane and ethane for example However this type of weathering tends to fill a crater quickly at first then more slowly as the crater rim gets worn down and less steep If liquid erosion were primarily responsible for the infill then the team would expect to see a lot of partially filled craters on Titan However this is not the case says Neish Instead we see craters at all stages some just beginning to be filled in some halfway and some that are almost completely full This suggests a process like windblown sand which fills craters and other features at a steady rate Solid materials under stress flow very slowly over time This is called viscous flow and it is like what happens when someone takes a scoop out of a fresh tub of whipped cream the material slowly flows in to fill the hole and flatten the surface Craters on icy satellites tend to get shallower over time as the ice flows viscously so it s possible that some of the shallow craters on Titan are simply much older or experienced a higher heat flow than the similarly sized fresh craters on Ganymede studied in this work However Titan s crust is mostly water ice and at the

    Original URL path: http://www.lpi.usra.edu/features/titan/012513/ (2016-02-15)
    Open archived version from archive

  • Martian Crater May Once Have Held Groundwater-Fed Lake
    channels originating within the crater wall end near a level that could have marked the surface of a lake Together these new observations suggest the formation of the carbonates and clay in a groundwater fed lake within the closed basin of the crater Some researchers propose the crater interior catching the water and the underground zone contributing the water could have been wet environments and potential habitats The findings were published in the January 20 online edition of Nature Geoscience Taken together the observations in McLaughlin Crater provide the best evidence for carbonate forming within a lake environment instead of being washed into a crater from outside said Joseph Michalski lead author of the paper which has five co authors Michalski also is affiliated with the Planetary Science Institute in Tucson Arizona and London s Natural History Museum Michalski and his co authors used the Compact Reconnaissance Imaging Spectrometer for Mars CRISM on the Mars Reconnaissance Orbiter MRO to check for minerals such as carbonates which are best preserved under nonacidic conditions The MRO team has made a concerted effort to get highly processed data products out to members of the science community like Michalski for analysis said CRISM Principal Investigator Scott Murchie of the Johns Hopkins University Applied Physics Laboratory in Laurel Maryland New results like this show why that effort is so important Launched in 2005 the Mars Reconnaissance Orbiter and its six instruments have provided more high resolution data about the Red Planet than all other Mars orbiters combined Data are made available for scientists worldwide to research analyze and report their findings A number of studies using CRISM data have shown rocks exhumed from the subsurface by meteor impact were altered early in martian history most likely by hydrothermal fluids Michalski said These fluids trapped in

    Original URL path: http://www.lpi.usra.edu/features/mro/012513/ (2016-02-15)
    Open archived version from archive

  • Center for Lunar Science and Exploration Releases Higher Education Lunar Resources
    material that teachers anywhere in the world can access and incorporate into their classrooms The newly designed Higher Education Lunar Consortium webpage provides access to such resources as Classroom Illustrations Downloadable classroom illustrations with instructional captions for educational use 3D Models 3D models currently available include Linné Crater Tycho Crater and Schrödinger Basin Laboratory Exercises Exercises that can be integrated into planetary geology courses or can stand alone as a way to illustrate planetary processes such as impact cratering Lunar Sample Atlases Libraries of images taken in the Lunar Sample Laboratory and other research laboratories including the Apollo Thin Section atlas and the Virtual Microscope catalog Lunar Image Atlases Links to a number of lunar image atlases including Apollo surface panoramas and the Lunar Orbiter Photo Gallery Video Resources Including flyovers simulations and the Moon 101 Lecture Series Lunar Analogue Data Sites Extensive information about Barringer Meteor Crater and the Black Point Lava Flow in Arizona Lunar related Textbooks Electronic versions of a number of essential books for lunar researchers including The Geologic History of the Moon Planetary Science A Lunar Perspective and Lunar Sourcebook A User s Guide to the Moon Other resources available include PPT slide sets and

    Original URL path: http://www.lpi.usra.edu/features/nlsi/011113/ (2016-02-15)
    Open archived version from archive

  • Cassini Suggests Icing on a Lake
    think can be building blocks for the more complex chemistry from which life arose Cassini has seen a vast network of these hydrocarbon seas cover Titan s northern hemisphere while a more sporadic set of lakes bejewels the southern hemisphere Up to this point Cassini scientists assumed that Titan lakes would not have floating ice because solid methane is denser than liquid methane and would sink But the new model considers the interaction between the lakes and the atmosphere resulting in different mixtures of compositions pockets of nitrogen gas and changes in temperature The result scientists found is that winter ice will float in Titan s methane and ethane rich lakes and seas if the temperature is below the freezing point of methane 297 F 90 4 K The scientists realized all the varieties of ice they considered would float if they were composed of at least 5 air which is an average composition for young sea ice on Earth Air on Titan has significantly more nitrogen than Earth air and almost no oxygen If the temperature drops by just a few degrees the ice will sink because of the relative proportions of nitrogen gas in the liquid versus the solid Temperatures close to the freezing point of methane could lead to both floating and sinking ice that is a hydrocarbon ice crust above the liquid and blocks of hydrocarbon ice on the bottom of the lake bed Scientists haven t entirely figured out what color the ice would be although they suspect it would be colorless as it is on Earth perhaps tinted reddish brown from Titan s atmosphere We now know it s possible to get methane and ethane rich ice freezing over on Titan in thin blocks that congeal together as it gets colder similar to what

    Original URL path: http://www.lpi.usra.edu/features/cassini/011113/ (2016-02-15)
    Open archived version from archive

  • Researchers Identify Water-Rich Meteorite Linked to Mars Crust
    is different from any previously studied martian meteorite The research is published in the January 3 edition of Science Express The contents of this meteorite may challenge many long held notions about martian geology said John Grunsfeld associate administrator for NASA s Science Mission Directorate These findings also present an important reference frame for the Curiosity rover as it searches for reduced organics in the minerals exposed in the bedrock of Gale Crater NWA 7034 is made of cemented fragments of basalt rock that forms from rapidly cooled lava The fragments are primarily feldspar and pyroxene most likely from volcanic activity This unusual meteorite s chemistry matches that of the martian crust as measured by NASA s Mars Exploration Rovers and Mars Odyssey Orbiter This martian meteorite has everything in its composition that you d want in order to further our understanding of the Red Planet said Carl Agee leader of the analysis team and director and curator at the University of New Mexico s Institute of Meteoritics in Albuquerque This unique meteorite tells us what volcanism was like on Mars 2 billion years ago It also gives us a glimpse of ancient surface and environmental conditions on Mars that no other meteorite has ever offered The research team included groups at the University of California at San Diego and the Carnegie Institution in Washington Experiments were conducted to analyze mineral and chemical composition age and water content Researchers theorize the large amount of water contained in NWA 7034 may have originated from interaction of the rocks with water present in Mars crust The meteorite also has a different mixture of oxygen isotopes than has been found in other martian meteorites which could have resulted from interaction with the martian atmosphere Most martian meteorites are divided into three rock types

    Original URL path: http://www.lpi.usra.edu/features/meteorites/011113/ (2016-02-15)
    Open archived version from archive



  •