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Massive
Mountain Range Imaged on Saturn's Moon Titan
12.12.06
The
tallest mountains ever seen on Titan -- coated with layers of
organic material and blanketed by clouds -- have been imaged on
Saturn's moon Titan by NASA's Cassini spacecraft.
(and
caption)
This
composite image shows a massive mountain range running just
south of Titan's equator.
Image
credit: NASA/JPL/University of Arizona
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"We see a massive
mountain range that kind of reminds me of the Sierra Nevada
mountains in the western United States. This mountain range is
continuous and is nearly 100 miles long," said Dr. Bob
Brown, team leader of the Cassini visual and infrared mapping
spectrometer at the University of Arizona, Tucson.
During
an Oct. 25 flyby designed to obtain the highest resolution
infrared views of Titan yet, Cassini resolved surface features as
small as 400 meters (1,300 feet). The images reveal a large
mountain range, dunes, and a deposit of material that resembles a
volcanic flow. These data, together with radar data from previous
flybys, provide new information on the height and composition of
geologic features on Titan.
If Titan were Earth, these
mountains would lie south of the equator, somewhere in New
Zealand. The range is about 150 kilometers long (93 miles) and 30
kilometers (19 miles) wide and about 1.5 kilometers (nearly a
mile) high. Deposits of bright, white material, which may be
methane "snow" or exposures of some other organic
material, lie at the top of the mountain ridges.
"These
mountains are probably as hard as rock, made of icy materials,
and are coated with different layers of organics," said Dr.
Larry Soderblom, Cassini interdisciplinary scientist at the U.S.
Geological Survey, Flagstaff, Ariz.
He added, "There
seem to be layers and layers of various coats of organic 'paint'
on top of each other on these mountain tops, almost like a
painter laying the background on a canvas. Some of this organic
gunk falls out of the atmosphere as rain, dust, or smog onto the
valley floors and mountain tops, which are coated with dark spots
that appear to be brushed, washed, scoured and moved around the
surface."
The mountains probably formed when
material welled up from below to fill the gaps opened when
tectonic plates pull apart, similar to the way mid-ocean ridges
are formed on Earth.
(and
caption)
This
image shows two views of an area on Titan riddled by mountain
ranges that were probably produced by tectonic forces.
Image
credit: NASA/JPL/University of Arizona
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Separately, the radar and
infrared data are difficult to interpret, but together they are a
powerful combination. In the infrared images, one can see the
shadows of the mountains, and in radar, one can see their shape.
But when combined, scientists begin to see variations on the
mountains, which is essential to unraveling the mysteries of the
geologic processes on Titan.
A fan-shaped feature,
possibly a remnant of a volcanic flow, is also visible in the
infrared images. The radar instrument imaged this flow and a
circular feature from which the flow seems to emanate on a
previous flyby, but not in this level of detail.
"The
evidence is mounting that this circular feature is a volcano,"
said Dr. Rosaly Lopes, Cassini radar team member at NASA's Jet
Propulsion Laboratory, Pasadena, Calif. "With radar data
alone, we identified it as a possible volcano, but the
combination of radar and infrared makes it much clearer."
Near the wrinkled, mountainous terrain are clouds in
Titan's southern mid latitudes whose source continues to elude
scientists. These clouds are probably methane droplets that may
form when the atmosphere on Titan cools as it is pushed over the
mountains by winds.
The composition of dunes that run
across much of Titan is also much clearer. "The dunes seem
to consist of sand grains made of organics, built on water-ice
bedrock, and there may also be some snow and bright deposits,"
Brown said.
Titan is a complex place and scientists are
uncovering the secrets of the surface, one flyby at a time.
Scientists hope to get more clues from the next Titan flyby, on
Dec. 12.
For the new infrared images of the mountains
visit The
Scientific Frontline Cassini Gallery
Source
/ Credit: NASA
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