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NASA
Finds Hydrocarbons on Saturn's Moon Hyperion
Wednesday, July 4, 2007
PASADENA
, Calif. - NASA's Cassini spacecraft has revealed for the first
time surface details of Saturn's moon Hyperion, including
cup-like craters filled with hydrocarbons that may indicate more
widespread presence in our solar system of basic chemicals
necessary for life.
Image
contains 3 HOT SPOTS to
full
captions and Hi-Res Images.
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credit: NASA/JPL/University of Arizona/Ames/Space Science
Institute
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Hyperion yielded some of
its secrets to the battery of instruments aboard Cassini as the
spacecraft flew close by in September 2005. Water and carbon
dioxide ices were found, as well as dark material that fits the
spectral profile of hydrocarbons.
A paper appearing in
the July 5 issue of Nature reports details of Hyperion's surface
craters and composition observed during this flyby, including
keys to understanding the moon's origin and evolution over 4.5
billion years. This is the first time scientists were able to map
the surface material on Hyperion.
"Of special
interest is the presence on Hyperion of
hydrocarbons--combinations of carbon and hydrogen atoms that are
found in comets, meteorites, and the dust in our galaxy,"
said Dale Cruikshank, a planetary scientist at NASA's Ames
Research Center, Moffett Field, Calif., and the paper's lead
author. "These molecules, when embedded in ice and exposed
to ultraviolet light, form new molecules of biological
significance. This doesn't mean that we have found life, but it
is a further indication that the basic chemistry needed for life
is widespread in the universe."
Cassini's
ultraviolet imaging spectrograph and visual and infrared mapping
spectrometer captured compositional variations in Hyperion's
surface. These instruments, capable of mapping mineral and
chemical features of the moon, sent back data confirming the
presence of frozen water found by earlier ground-based
observations, but also discovered solid carbon dioxide (dry ice)
mixed in unexpected ways with the ordinary ice. Images of the
brightest regions of Hyperion's surface show frozen water that is
crystalline in form, like that found on Earth.
"Most
of Hyperion's surface ice is a mix of frozen water and organic
dust, but carbon dioxide ice is also prominent. The carbon
dioxide is not pure, but is somehow chemically attached to other
molecules," explained Cruikshank.
Prior spacecraft
data from other moons of Saturn, as well as Jupiter's moons
Ganymede and Callisto, suggest that the carbon dioxide molecule
is "complexed," or attached with other surface material
in multiple ways. "We think that ordinary carbon dioxide
will evaporate from Saturn's moons over long periods of time,"
said Cruikshank, "but it appears to be much more stable when
it is attached to other molecules."
"The
Hyperion flyby was a fine example of Cassini's multi-wavelength
capabilities. In this first-ever ultraviolet observation of
Hyperion, the detection of water ice tells us about compositional
differences of this bizarre body," said Amanda Hendrix,
Cassini scientist on the ultraviolet imaging spectrograph at
NASA's Jet Propulsion Laboratory, Pasadena, Calif.
Source:
NASA / JPL
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