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Science Forum Index » Astro Forum » Cassini Images Mammoth Cloud Engulfing Titan's North Pole
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 Posted: Thu Feb 01, 2007 1:20 pm |
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http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=720
Cassini Images Mammoth Cloud Engulfing Titan's North Pole
Jet Propulsion Laboratory
NEWS RELEASE: 2007-010
February 1, 2007
A giant cloud half the size of the United States has been imaged on
Saturn's moon Titan by the Cassini spacecraft. The cloud may be
responsible for the material that fills the lakes discovered last year
by Cassini's radar instrument.
Cloaked by winter's shadow, this cloud has now come into view as
winter
turns to spring. The cloud extends down to 60 degrees north latitude,
is
roughly 2,400 kilometers (1,490 miles) in diameter and engulfs almost
the entire north pole of Titan.
The new image was acquired on Dec. 29, 2006, by Cassini's visual and
infrared mapping spectrometer. Scientific models predicted this cloud
system, but it had never been imaged in such detail before.
The cloud image is available at: http://www.nasa.gov/cassini ,
http://saturn.jpl.nasa.gov , and http://wwwvims.lpl.arizona.edu .
"We knew this cloud had to be there but were amazed at its size and
structure," said Dr. Christophe Sotin of the University of Nantes,
France, a member of the visual and infrared mapping spectrometer team
and distinguished visiting scientist at NASA's Jet Propulsion
Laboratory, Pasadena, Calif. "This cloud system may be a key element
in
the global formation of organics and their interaction with the
surface."
The same cloud system seen on Dec. 29, was still there two weeks later
during a Jan. 13, 2007, flyby, even though observing conditions were
slightly less favorable than in December.
The Cassini radar team reported last year that the lakes at the north
pole are partly filled, and some appear to have evaporated, likely
contributing to this cloud formation, which is made up of ethane,
methane and other organics. These findings reinforce the idea that
methane rains down onto the surface to form lakes and then evaporates
to
form clouds. Scientists compare this methane cycle to the hydrological
cycle on Earth, dubbing it "methane-ologic cycle."
Ground-based observations show this Titan cloud system comes and goes
with the seasons. A season on Titan lasts approximately seven Earth
years. Based on the global circulation models, it seems that such
cloud
activity can last about 25 Earth years before almost vanishing for
four
to five years, and then appearing again for 25 years.
Scientists expect this cloud to be around for several years. As the
seasons change, scientists expect a shift of these clouds and lakes
from
the north pole to the south pole. On Titan's south pole, scientists
have
seen only one kidney-shaped lake with Cassini's imaging cameras.
"With 16 more flybys to come this year, we should have the opportunity
to monitor the evolution of this cloud system over time," said Dr.
Stephane Le Mouelic, working with the Cassini visual and infrared
mapping spectrometer team, and also at the University of Nantes.
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. JPL, a division of
the California Institute of Technology in Pasadena, manages the
Cassini-Huygens mission for NASA's Science Mission Directorate,
Washington. The Cassini orbiter was designed, developed and assembled
at
JPL. The visual and infrared mapping spectrometer team is based at the
University of Arizona, Tucson.
Contacts:
Carolina Martinez 818-354-9382
Jet Propulsion Laboratory, Pasadena, Calif. |
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