From: LARRY KLAES (ljk4_at_msn.com)
Date: Wed Jun 08 2005 - 13:16:53 PDT
>From: "NASA Jet Propulsion Laboratory" <info_at_jpl.nasa.gov>
>Reply-To: <info_at_jpl.nasa.gov>
>To: "Larry Klaes" <ljk4_at_msn.com>
>Subject: Scientists Discover Possible Titan Volcano
>Date: Wed, 08 Jun 2005 12:41:05 -0700
>
>MEDIA RELATIONS OFFICE
>JET PROPULSION LABORATORY
>CALIFORNIA INSTITUTE OF TECHNOLOGY
>NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
>PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
>http://www.jpl.nasa.gov
>
>Carolina Martinez (818) 354-9382
>Jet Propulsion Laboratory, Pasadena, Calif.
>
>News Release: 2005-096 June 8, 2005
>
>Scientists Discover Possible Titan Volcano
>
>A recent flyby of Saturn's hazy moon Titan by the Cassini spacecraft has
>revealed
>evidence of a possible volcano, which could be a source of methane in
>Titan's
>atmosphere.
>
>Images taken in infrared light show a circular feature roughly 30
>kilometers (19 miles) in
>diameter that does not resemble any features seen on Saturn's other icy
>moons.
>Scientists interpret the feature as an "ice volcano," a dome formed by
>upwelling icy
>plumes that release methane into Titan's atmosphere. The findings appear
>in the June
>9 issue of Nature.
>
>"Before Cassini-Huygens, the most widely accepted explanation for the
>presence of
>methane in Titan's atmosphere was the presence of a methane-rich
>hydrocarbon
>ocean," said Dr. Christophe Sotin, distinguished visiting scientist at
>NASA's Jet
>Propulsion Laboratory, Pasadena, Calif.
>
>"The suite of instruments onboard Cassini and the observations at the
>Huygens landing
>site reveal that a global ocean is not present," said Sotin, a team member
>of the Cassini
>visual and infrared mapping spectrometer instrument and professor at the
>Université de
>Nantes, France.
>
>"Interpreting this feature as a cryovolcano provides an alternative
>explanation for the
>presence of methane in Titan's atmosphere. Such an interpretation is
>supported by
>models of Titan's evolution," Sotin said.
>
>Titan, Saturn's largest moon, is the only known moon to have a significant
>atmosphere,
>composed primarily of nitrogen, with 2 to 3 percent methane. One goal of
>the Cassini
>mission is to find an explanation for what is replenishing and maintaining
>this
>atmosphere. This dense atmosphere makes the surface very difficult to
>study with
>visible-light cameras, but infrared instruments like the visual and
>infrared mapping
>spectrometer can peer through the haze. Infrared images provide
>information about
>both the composition and the shape of the area studied.
>
>The highest resolution image obtained by the visual and infrared mapping
>spectrometer
>instrument covers an area 150 kilometers square (90 miles) that includes a
>bright
>circular feature about 30 kilometers (19 miles) in diameter, with two
>elongated wings
>extending westward. This structure resembles volcanoes on Earth and Venus,
>with
>overlapping layers of material from a series of flows.
>
>"We all thought volcanoes had to exist on Titan, and now we've found the
>most
>convincing evidence to date. This is exactly what we've been looking for,"
>said Dr.
>Bonnie Buratti, team member of the Cassini visual and infrared mapping
>spectrometer
>at JPL.
>
>In the center of the area, scientists clearly see a dark feature that
>resembles a caldera,
>a bowl-shaped structure formed above chambers of molten material. The
>material
>erupting from the volcano might be a methane-water ice mixture combined
>with other
>ices and hydrocarbons. Energy from an internal heat source may cause these
>materials
>to upwell and vaporize as they reach the surface. Future Titan flybys will
>help
>determine whether tidal forces can generate enough heat to drive the
>volcano, or
>whether some other energy source must be present. Black channels seen by
>the
>European Space Agency's Huygens probe, which piggybacked on Cassini and
>landed
>on Titan's surface in January 2005, could have been formed by erosion from
>liquid
>methane rains following the eruptions.
>
>Scientists have considered other explanations. They say the feature cannot
>be a cloud
>because it does not appear to move and it is the wrong composition.
>Another
>alternative is that an accumulation of solid particles was transported by
>gas or liquid,
>similar to sand dunes on Earth. But the shape and wind patterns don't
>match those
>normally seen in sand dunes.
>
>The data for these findings are from Cassini's first targeted flyby of
>Titan on Oct. 26,
>2004, at a distance of 1,200 kilometers (750 miles) from the moon's
>surface.
>
>The visual and infrared mapping spectrometer instrument can detect 352
>wavelengths
>of light from 0.35 to 5.1 micrometers. It measures the intensities of
>individual
>wavelengths and uses the data to infer the composition and other properties
>of the
>object that emitted the light; each chemical has a unique spectral
>signature that can be
>identified.
>
>Forty-five flybys of Titan are planned during Cassini's four-year prime
>mission. The next
>one is Aug. 22, 2005. Radar data of the same sites observed by the visual
>and infrared
>mapping spectrometer may provide additional information.
>
>For more information about the Cassini-Huygens mission visit
>http://saturn.jpl.nasa.gov
>and http://www.nasa.gov/cassini . The visual and infrared mapping
>spectrometer page
>is at http://wwwvims.lpl.arizona.edu .
>
>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 mission for
>NASA's
>Science Mission Directorate, Washington, D.C. The Cassini orbiter was
>designed,
>developed and assembled at JPL. The visual and infrared mapping
>spectrometer team
>is based at the University of Arizona.
>
>-end-
>
>
>
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