Astro Blog

Source:   Ken Kremer, Universe Today Excerpt: A new world in our Solar System is about to be unveiled for the first time – the mysterious protoplanet Vesta, which is the second most massive object in the main Asteroid Belt between Mars and Jupiter. NASA’s Dawn Asteroid orbiter has entered its final approach phase to Vesta and for the first time is snapping images that finally exceed those taken several years ago by the iconic Hubble Space Telescope. …See also "Revolutionary Dawn Closing in on Asteroid Vesta with Opened Eyes"   www.universetoday.com/84052/revolutionary-dawn-closing-in-on-asteroid-vesta-with-opened-eyes/ www.universetoday.com/86474/dawn-closing-in-on-asteroid-vesta-as-views-exceed-hubble/

Source:    NASA RELEASE: 11-197 Excerpt: NASA's Dawn spacecraft is on track to begin the first extended visit to a large asteroid. The mission expects to go into orbit around Vesta on July 16 and begin gathering science data in early August. Vesta resides in the main asteroid belt and is thought to be the source of a large number of meteorites that fall to Earth….The spacecraft will move into a high altitude mapping orbit, about 420 miles (680 kilometers) above the surface to systematically map the parts of Vesta's surface illuminated by the sun; collect stereo images to see topographic highs and lows; acquire higher resolution data to map rock types at the surface; and learn more about Vesta's thermal properties. Dawn then will move even closer, to a low-altitude mapping orbit approximately 120 miles (200 kilometers) above the surface. For more information about Dawn, visit:  http://www.nasa.gov/dawn   www.nasa.gov/home/hqnews/2011/jun/HQ_11-197_Dawn_Nears_Vesta.h

Source:    NASA RELEASE: 11-199 Excerpt:  Analysis of samples returned by NASA's Genesis mission indicates our sun and its inner planets may have formed differently than scientists previously thought. "…findings show that all solar system objects, including the terrestrial planets, meteorites and comets, are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co-investigator from Centre de Recherches Petrographiques et Geochimiques in Nancy, France and the lead author of the second new Science paper. "Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system." For more information on the Genesis mission, visit: genesismission.jpl.nasa.gov www.nasa.gov/home/hqnews/2011/jun/HQ_11-199_Genesis.html

Source:    NASA RELEASE: 11-196 Excerpt: NASA's Cassini spacecraft has discovered the best evidence yet for a large-scale saltwater reservoir beneath the icy crust of Saturn's moon Enceladus. The data came from the spacecraft's direct analysis of salt-rich ice grains close to the jets ejected from the moon. …"There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus's icy surface," said Frank Postberg, a Cassini team scientist at the University of Heidelberg, Germany, and the lead author on the paper.  …This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets," said Nicolas Altobelli, the European Space Agency's project scientist for Cassini. …Cassini's ultraviolet imaging spectrograph also recently obtained complemen

Source:    NASA RELEASE: 11-186 Excerpt: Data from MESSENGER [MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft], the first spacecraft to orbit Mercury, is giving scientists important clues to the origin of the planet and its geological history  ...Two decades ago, Earth-based radar images showed deposits thought to consist of water ice and perhaps other ices near Mercury's north and south poles ... preserved on the cold, permanently shadowed floors of high-latitude impact craters. MESSENGER is testing this idea by measuring the floor depths of craters near Mercury's north pole. For more information about the mission, visit: http://www.nasa.gov/messenger messenger.jhuapl.edu/news_room/details.php  

Source:   NASA Excerpt: Collisions are at the core of solar system formation …and continue to be one of the most important processes throughout our solar system. ... the Earth-Moon system most likely formed by the impact of the early Earth with another planet half Earth's size ...NASA scientists have created their own impacts to study this important process -- on the Moon during the LCROSS mission and on comet Tempel 1 during the Deep Impact mission. solarsystem.nasa.gov/yss/display.cfm

Source:   Johanna L. Miller, Physics Today Excerpt: Radar data reveal a solid reservoir that contains almost as much carbon dioxide as the planet’s entire atmosphere. …because Mars doesn’t have a large moon, it… wobbles by up to tens of degrees on time scales of hundreds of thousands of years…. a profound effect on the planet’s polar icecaps. Substantial amounts of material sublimate and are redeposited, creating a complex structure of overlapping layered deposits. Most of those deposits are primarily water ice. …but now, data from the Mars Reconnaissance Orbiter reveal at least one large deposit of CO2 ice…if ...vaporized, as it certainly was at some point in the past and will be again in the future, it could nearly double the average pressure of Mars’s thin, CO2-based atmosphere. See also: www.nasa.gov/mission_pages/MRO/news/mro20100526.html physicstoday.org/resource/1/phtoad/v64/i6/p12_s1