SETI bioastro: Fw: Cassini Exposes Puzzles About Ingredients In Saturn's Rings

From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Jul 02 2004 - 19:29:42 PDT

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    ----- Original Message -----
    From: NASA Jet Propulsion Laboratory<mailto:info_at_jpl.nasa.gov>
    To: ljk4_at_msn.com<mailto:ljk4_at_msn.com>
    Sent: Friday, July 02, 2004 6:48 PM
    Subject: Cassini Exposes Puzzles About Ingredients In Saturn's Rings

    MEDIA RELATIONS OFFICE
    JET PROPULSION LABORATORY
    CALIFORNIA INSTITUTE OF TECHNOLOGY
    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
    PASADENA, CALIFORNIA 91109. TELEPHONE (818) 354-5011
    http://www.jpl.nasa.gov>

    Carolina Martinez (818) 354-5011
    Jet Propulsion Laboratory, Pasadena, Calif.

    Donald Savage (202) 358-1727

    NASA Headquarters, Washington

    News Release: 2004-170 July 2, 2004

    Cassini Exposes Puzzles About Ingredients In Saturn's Rings

    Just two days after the Cassini spacecraft entered Saturn orbit,
    preliminary science results are already beginning to show a complex
    and fascinating planetary system.

    One early result intriguing scientists concerns Saturn's Cassini
    Division, the large gap between the A and B rings. While Saturn's
    rings are almost exclusively composed of water ice, new findings show
    the Cassini Division contains relatively more "dirt" than ice.
    Further, the particles between the rings seem remarkably similar to
    the dark material that scientists saw on Saturn's moon, Phoebe. These
    dark particles refuel the theory that the rings might be the remnants
    of a moon. The F ring was also found to contain more dirt.

    Another instrument on Cassini has detected large quantities of oxygen
    at the edge of the rings. Scientists are still trying to understand
    these results, but they think the oxygen may be left over from a
    collision that occurred as recently as January of this year.

    "In just two days, our ideas about the rings have been expanded
    tremendously," said Dr. Linda Spilker, of NASA's Jet Propulsion
    Laboratory, Pasadena, Calif., deputy project scientist for the
    Cassini-Huygens mission. "The Phoebe-like material is a big surprise.
    What puzzles us is that the A and B rings are so clean and the Cassini
    Division between them appears so dirty."

    The visual and infrared mapping spectrometer onboard Cassini revealed
    the dirt mixed with the ice in the Cassini Division and in other small
    gaps in the rings, as well as in the F ring.

    "The surprising fingerprint in the data is that the dirt appears
    similar to what we saw at Phoebe. In the next several months we will
    be looking for the origin of this material," said Dr. Roger Clark, of
    the U.S. Geological Survey, Denver, Colo., and a member of the Cassini
    science team.

    Cassini's ultraviolet imaging instrument detected the sudden and
    surprising increase in the amount of atomic oxygen at the edge of the
    rings. The finding leads scientists to hypothesize that something may
    have collided with the main rings, producing the excess oxygen.

    Dr. Donald Shemansky of the University of Southern California, Los
    Angeles, co-investigator for Cassini's ultraviolet imaging
    spectrograph instrument, said, "What is surprising is the evidence of
    a strong, sudden event during the observation period causing
    substantial variation in the oxygen distribution and abundance."
    Although atomic oxygen has not been previously observed, its presence
    is not a surprise because hydroxyl was discovered earlier from Hubble
    Space Telescope observations, and these chemicals are both products of
    water chemistry.

    Cassini's examination of Saturn's atmosphere began while the
    spacecraft was still approaching the planet. Winds on Saturn near the
    equator decrease dramatically with altitude above the cloud tops. The
    winds fall off by as much 140 meters per second (approximately 300
    miles per hour) over an altitude range of 300 kilometers
    (approximately 200 miles) in the upper stratosphere. This is the first
    time winds have been measured at altitudes so high in Saturn's
    atmosphere.

    "We are finally defining the wind field in three dimensions, and it is
    very complex," said Dr. Michael Flasar of NASA Goddard Space Flight
    Center, Greenbelt, Md., principal investigator for Cassini's composite
    infrared spectrometer. "Temperature maps obtained now that Cassini is
    orbiting Saturn are expected to show more detail, helping us to
    unravel the riddles of Saturn's winds above the cloud tops."

    Early Friday (Pacific Time), Cassini imaged Saturn's largest moon
    Titan, one of the prime targets for the mission. Titan is thought to
    harbor simple organic compounds that may be important in understanding
    the chemical building blocks that led to life on Earth. Although too
    cold to support life now, Titan serves as a frozen vault to see what
    early Earth might have been like. Scientists will receive the new
    data and images from Titan later Friday.

    The Cassini-Huygens mission is a cooperative project of NASA, the
    European Space Agency and the Italian Space Agency. The Jet Propulsion
    Laboratory, a division of the California Institute of Technology in
    Pasadena, manages the Cassini-Huygens mission for NASA's Office of
    Space Science, Washington, D.C. JPL designed, developed and assembled
    the Cassini orbiter.

    For the latest images and more information about the Cassini-Huygens
    mission, visit
    http://saturn.jpl.nasa.gov> and
    http://www.nasa.gov/cassini> .
     

    -end-


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