[FPSPACE] FW: NASA's Cassini Reveals Lake-Like Feature on Titan

[LARRY KLAES]

>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: NASA's Cassini Reveals Lake-Like Feature on Titan
>Date: Tue, 28 Jun 2005 12:08:16 -0700
>
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>Carolina Martinez (818) 354-9382
>Jet Propulsion Laboratory, Pasadena, Calif.
>
>Erica Hupp/Dolores Beasley (202/358-1237/1753)
>NASA Headquarters, Washington
>
>Preston Dyches (720) 974-5859
>Cassini Imaging Central Laboratory for Operations
>Space Science Institute, Boulder, Colo.
>
>News Release: 2005-103				June 28, 2005
>
>NASA's Cassini Reveals Lake-Like Feature on Titan
>
>Scientists are fascinated by a dark, lake-like feature recently observed on
>Saturn's moon Titan. NASA's Cassini spacecraft captured a series of images
>showing a marking, darker than anything else around it. It is remarkably 
>lake-like,
>with smooth, shore-like boundaries unlike any seen previously on Titan.
>
>"I'd say this is definitely the best candidate we've seen so far for a 
>liquid
>hydrocarbon lake on Titan," said Dr. Alfred McEwen, Cassini imaging team
>member and a professor at the University of Arizona, Tucson. The suspected
>lake area measures 234 kilometers long by 73 kilometers wide (145 miles by 
>45
>miles), about the size of Lake Ontario, on the U.S. Canadian border.
>
>"This feature is unique in our exploration of Titan so far," said Dr. 
>Elizabeth
>Turtle, Cassini imaging team associate at the University of Arizona. "Its 
>perimeter
>is intriguingly reminiscent of the shorelines of lakes on Earth that are 
>smoothed
>by water erosion and deposition."
>
>The feature lies in Titan's cloudiest region, which is presumably the most 
>likely
>site of recent methane rainfall. This, coupled with the shore-like 
>smoothness of
>the feature's perimeter makes it hard for scientists to resist speculation 
>about
>what might be filling the lake, if it indeed is one.
>
>"It's possible that some of the storms in this region are strong enough to 
>make
>methane rain that reaches the surface," said Cassini imaging team member 
>Dr.
>Tony DelGenio of NASA's Goddard Institute for Space Studies in New York.
>
>"Given Titan's cold temperatures, it could take a long time for any liquid 
>methane
>collecting on the surface to evaporate. So it might not be surprising for a
>methane-filled lake to persist for a long time," DelGenio added.
>Despite earlier predictions, no definitive evidence for open bodies of 
>liquid has
>been found on Titan. Cassini has not yet been in a favorable position for 
>using its
>cameras to check for glints from possible surface liquids in the south 
>polar
>region.
>
>"Eventually, as the seasons change over a few years, the convective clouds 
>may
>migrate northward to lower latitudes," said DelGenio, "If so, it will be 
>interesting to
>see whether the Cassini cameras record changes in the appearance of the
>surface as well."
>
>"An alternate explanation is that this feature was once a lake, but has 
>since dried
>up, leaving behind dark deposits," Turtle said. Yet another possibility is 
>that the
>lake is simply a broad depression filled by dark, solid hydrocarbons 
>falling from
>the atmosphere onto Titan's surface. In this case, the smooth outline might 
>be
>the result of a process unrelated to rainfall, such as a sinkhole or a 
>volcanic
>caldera.
>
>"It reminds me of the lava lakes seen on Jupiter's moon, Io," Dr. Torrence
>Johnson, an imaging team member at NASA's Jet Propulsion Laboratory in
>Pasadena, Calif.
>
>"It is already clear that whatever this lake-like feature turns out to be, 
>it is only
>one of many puzzles that Titan will throw at us as we continue our
>reconnaissance of the surface over the next few years," said Dr. Carolyn 
>Porco,
>imaging team leader at the Space Science Institute in Boulder, Colo.
>
>Thirty-nine more Titan flybys are planned for Cassini's prime mission. In 
>future
>flybys the science teams will search for opportunities to observe the lake 
>feature
>again and to look for mirror-like reflections from smooth surfaces 
>elsewhere on
>Titan. Such reflections would strongly support the presence of liquids.
>
>The Cassini-Huygens mission is a cooperative project of NASA, the European
>Space Agency and the Italian Space Agency. JPL manages the Cassini mission
>for NASA's Science Mission Directorate, Washington. The Cassini orbiter and 
>its
>two onboard cameras were designed, developed and assembled at JPL. The
>imaging team is based at the Space Science Institute in Boulder.
>
>To view a computer-enhanced image of the feature and a three-frame movie
>showing the evolution of nearby clouds on the Internet, visit:
>http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and 
>http://ciclops.org .
>
>-end-
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