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Posts Tagged ‘Dione’

Cassini Finds Hints Of Activity At Saturn Moon Dione


Image credit: NASA/JPL/Space Science Institute

Image credit: NASA/JPL/Space Science Institute

From a distance, most of the Saturnian moon Dione resembles a bland cueball. Thanks to close-up images of a 500-mile-long (800-kilometer-long) mountain on the moon from NASA’s Cassini spacecraft, scientists have found more evidence for the idea that Dione was likely active in the past. It could still be active now.

“A picture is emerging that suggests Dione could be a fossil of the wondrous activity Cassini discovered spraying from Saturn’s geyser moon Enceladus or perhaps a weaker copycat Enceladus,” said Bonnie Buratti of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., who leads the Cassini science team that studies icy satellites. “There may turn out to be many more active worlds with water out there than we previously thought.”

Other bodies in the solar system thought to have a subsurface ocean – including Saturn’s moons Enceladus and Titan and Jupiter’s moon Europa – are among the most geologically active worlds in our solar system. They have been intriguing targets for geologists and scientists looking for the building blocks of life elsewhere in the solar system. The presence of a subsurface ocean at Dione would boost the astrobiological potential of this once-boring iceball.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-178

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Cassini Detects Hint of Fresh Air at Dione


Image credit: NASA/JPL/Space Science Institute

Image credit: NASA/JPL/Space Science Institute

NASA’s Cassini spacecraft has “sniffed” molecular oxygen ions around Saturn’s icy moon Dione for the first time, confirming the presence of a very tenuous atmosphere. The oxygen ions are quite sparse – one for every 0.67 cubic inches of space (one for every 11 cubic centimeters of space) or about 2,550 per cubic foot (90,000 per cubic meter) – show that Dione has an extremely thin neutral atmosphere.

At the Dione surface, this atmosphere would only be as dense as Earth’s atmosphere 300 miles (480 kilometers) above the surface. The detection of this faint atmosphere, known as an exosphere, is described in a recent issue of the journal Geophysical Research Letters.

“We now know that Dione, in addition to Saturn’s rings and the moon Rhea, is a source of oxygen molecules,” said Robert Tokar, a Cassini team member based at Los Alamos National Laboratory, Los Alamos, N.M., and the lead author of the paper. “This shows that molecular oxygen is actually common in the Saturn system and reinforces that it can come from a process that doesn’t involve life.”

Full Story: http://www.jpl.nasa.gov/news/news.cfm?release=2012-056

Exosphere Confirmed at Saturn’s Moon Dione

February 29, 2012 Leave a comment

The Cassini spacecraft flew by Dione, one of Saturn’s icy moons, on 7 April 2010. During that flyby, instruments detected molecular oxygen ions around the moon. Tokar et al. used those measurements to estimate the density of the molecular oxygen ions to be in the range of 0.01 to 0.09 ions per cubic centimeter (or ions per 0.06 cubic inches). These molecular oxygen ions are produced when neutral molecules are ionized; the measurements confirm that a neutral exosphere surrounds Dione.

Full Story: http://www.agu.org/news/press/jhighlight_archives/2012/2012-02-29.shtml#six

NASA’s Cassini Delivers Holiday Treats From Saturn

December 22, 2011 Leave a comment

Image credit: NASA/JPL-Caltech/SSI

Image credit: NASA/JPL-Caltech/SSI

No team of reindeer, but radio signals flying clear across the solar system from NASA’s Cassini spacecraft have delivered a holiday package of glorious images. The pictures, from Cassini’s imaging team, show Saturn’s largest, most colorful ornament, Titan, and other icy baubles in orbit around this splendid planet.

The release includes images of satellite conjunctions in which one moon passes in front of or behind another. Cassini scientists regularly make these observations to study the ever-changing orbits of the planet’s moons. But even in these routine images, the Saturnian system shines. A few of Saturn’s stark, airless, icy moons appear to dangle next to the orange orb of Titan, the only moon in the solar system with a substantial atmosphere. Titan’s atmosphere is of great interest because of its similarities to the atmosphere believed to exist long ago on the early Earth.

The images are online at: http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org .

Full Story: http://www.jpl.nasa.gov/news/news.cfm?release=2011-393

Journal Highlights on History of Mars, Dione’s Atmosphere & Saturn’s Aurora

August 31, 2011 Leave a comment

  • New observations from the Compact Reconnaissance Imaging Spectrometer
    for Mars (CRISM) show the presence of multiple magmatic intrusions in
    the Valles Marineris canyon on Mars
  • A new study indicates that one of Saturn’s moons, Dione, probably has
    a tenuous atmosphere.
  • New observations of Saturn’s southern auroral oval made simultaneously
    in ultraviolet (UV) and infrared (IR) wavelengths show how complex and
    dynamic the auroral oval is.

Full Story: http://www.agu.org/news/press/jhighlight_archives/2011/2011-08-31.shtml