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.

Preston Dyches (720) 974-5823
Cassini Imaging Central Laboratory for Operations
Space Science Institute, Boulder, Colo.

Press Release: 2005-041 March 9, 2005

Cassini Images of Titan Reveal an Active, Earth-Like World

Saturn's largest and hazy moon, Titan, has a surface shaped
largely by Earth-like processes of tectonics, erosion, winds, and
perhaps volcanism. The findings are published in this week's
issue of the journal Nature.

Titan, long held to be a frozen analog of early Earth, has liquid
methane on its cold surface, unlike the water found on our home
planet. Among the new discoveries is what may be a long river,
roughly 1,500 kilometers long (930 miles). Scientists have also
concluded that winds on Titan blow a lot faster than the moon
rotates, a fact long predicted but never confirmed until now.

Tectonism (brittle fracturing and faulting) has clearly played a
role in shaping Titan's surface. "The only known planetary
process that creates large-scale linear boundaries is tectonism,
in which internal processes cause portions of the crust to
fracture and sometimes move either up, down or sideways," said
Dr. Alfred McEwen, Cassini imaging team member from the
University of Arizona, Tucson. "Erosion by fluids may accentuate
the tectonic fabric by depositing dark materials in low areas and
enlarging fractures. This interplay between internal forces and
fluid erosion is very Earth-like."

Cassini images collected during close flybys of the moon show
dark, curving and linear patterns in various regions on Titan,
but mostly concentrated near the south pole. Some extend up to
1,500 kilometers (930 miles) long. Images from the European
Space Agency's Huygens probe show clear evidence for small
channels a few kilometers long, probably cut by liquid methane.
Cassini imaging scientists suggest that the dark, curved and
linear patterns seen in the Cassini orbiter images of Titan may
also be channels, though there is no direct evidence for the
presence of fluids. If these features are channels, it would
make the ones near the south pole nearly as long as the Snake
River, which originates in Wyoming and flows across four states.

Since most of the cloud activity observed on Titan by Cassini has
occurred over the south pole, scientists believe this may be
where the cycle of methane rain, channel carving, runoff, and
evaporation is most active, a hypothesis that could explain the
presence of the extensive channel-like features seen in this
region.

In analyzing clouds of Titan's lower atmosphere, scientists have
concluded that the winds on Titan blow faster than the moon
rotates, a phenomenon called super-rotation. In contrast, the
jet streams of Earth blow slower than the rotation rate of our
planet.

"Models of Titan's atmosphere have indicated that it should super-
rotate just like the atmosphere of Venus, but until now there
have been no direct wind measurements to test the prediction,"
said Cassini imaging team member Dr. Tony Del Genio of NASA's
Goddard Institute for Space Studies, in New York. DelGenio made
the first computer simulation predicting Titan super-rotation a
decade ago.

Titan's winds are measured by watching its clouds move. Clouds
are rare on Titan, and those that can be tracked are often too
small and faint to be seen from Earth. Ten clouds have been
tracked by Cassini, giving wind speeds as high as 34 meters per
second (about 75 miles per hour) to the east -- hurricane
strength -- in Titan's lower atmosphere. "This result is
consistent with the predictions of Titan weather models, and it
suggests that we now understand the basic features of how
meteorology works on slowly rotating planets," said Del Genio.

"We've only just begun exploring the surface of Titan, but what's
struck me the most so far is the variety of the surface patterns
that we're seeing. The surface is very complex, and shows
evidence for so many different modification processes," said Dr.
Elizabeth Turtle, Cassini imaging team associate in the Lunar and
Planetary Laboratory at the University of Arizona, Tucson and co-
author of one of the papers in Nature.

"Throughout the solar system, we find examples of solid bodies
that show tremendous geologic variation across their surfaces.
One hemisphere often can bear little resemblance to the other,"
said Dr. Carolyn Porco, Cassini imaging team leader, Space
Science Institute, Boulder, Colo. "On Titan, it's very likely to
be this and more."

These results are based on Cassini orbiter images of Titan
collected over the last eight months during a distant flyby of
the south pole and three close encounters of Titan's equatorial
region. Cassini cameras have covered 30 percent of Titan's
surface, imaging features as small as 1 to 10 kilometers (0.6 to
6 miles). Cassini is scheduled to make 41 additional close Titan
flybys in the next three years.

For images and information on the Cassini mission visit
http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini and
http://ciclops.org .

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 Science Mission Directorate, Washington, D.C. The Cassini
orbiter was designed, developed and assembled at JPL.

-end-

wrote:
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

snip

In analyzing clouds of Titan's lower atmosphere, scientists have
concluded that the winds on Titan blow faster than the moon
rotates, a phenomenon called super-rotation. In contrast, the
jet streams of Earth blow slower than the rotation rate of our
planet.


Oh really? So the jet-streams on Earth blow from East to West. Can't say
I'd noticed.

Graham