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Color Movie |
Black & White Movie |
Cassini's radar mapper has obtained stereo views of close to 2 percent of
Titan's surface during 19 flybys over the last five years. The process of
making topographic maps from images is just getting started, but the
results already reveal some of the diversity of Titan's geologic features.
The prominent, roughly circular feature in the western part of this image
is an area known as Ganesa Macula. This 180-kilometer-(110-mile)-wide
feature crudely resembles steep-sided volcanic domes on Venus that were
imaged with the NASA Magellan spacecraft in the 1990s. It was therefore
hypothesized initially to be a cryovolcanic feature. The topographic map
derived from radar stereo shows that Ganesa as a whole is not elevated, as
would be expected for a volcano. Instead, it is tilted (low in the west,
high along the eastern margin). Other high and low areas with north-south
trending margins alternate to the east of Ganesa. Low areas are
consistently filled by radar-bright (rough) channels and flow deposits.
The largest of these, in the center of the map with two bright channels
leading to triangular fan structures on its western margin, is known as
Leliah Fluctus. Although Ganesa Macula could have originated as a
cryovolcanic feature (or perhaps as an impact crater, either of which
would account for its distinct circular outline), it appears to have been
extensively modified by both tectonic (faulting) and fluvial (erosion by
fluids derived from rainfall) processes.
The region shown here is centered near 50 degrees north latitude, 80
degrees west longitude, and is about 1,480 kilometers (920 miles) across.
The maps are in equirectangular projection with north at the top. The
images used for mapping were acquired during flybys on Oct. 26, 2004, and
Jan. 13, 2007 (known as Ta and T23). The Ta image is shown in black and
white at the top. It has a pixel spacing of 351 meters (about 1,200 feet).
Below, the same image is shown with color coding to indicate elevations,
as shown by the color bar at left. The total range of relief from purple
(low) to red (high) is 1,000 meters (about 3,300 feet).
Video clips showing a "flyover" of these regions are shown in Figure 1 (in
color) and Figure 2 (in black and white). These movies are vertically
exaggerated by 15 times. Elevation is shown in color, from purple (low) to
red (high).
The flight path starts by looking down at the area from the north, then
flies down to the northeast end of the map and looks more horizontally
across to the west. This gives an especially good view of the major flow
deposit Leilah Fluctus, the big bright area with two prominent bright
triangular extensions on its far (west) side. The flight path then rotates
down around the southern side of the area. Note the channels carved into
the mountains by the flows that created Leilah Fluctus. The high-standing
areas are generally more radar-dark and the low areas are filled with very
radar-bright material. This pattern of flow materials being extremely
bright is seen in many places on Titan and may have to do with the cobbles
(roughly fist-sized rocks) deposited by the flows. Such rocks would
reflect the radar signal much more strongly than smooth terrain does.
Finally, the flight path continues around the southern edge of Ganesa
Macula and then up across the map to look eastward across it. The circular
outline of Ganesa shows only in the black and white image and is a little
hard to see from this horizontal view.
The color movie (Figure 1) makes it clear that Ganesa is generally high on
the eastern side, with a few isolated very high peaks, seen in red, and
low on the western side. Other high and low areas with north-south
trending margins alternate to the east of Ganesa. Once again, low areas
are consistently filled by radar-bright (rocky) channels and flow
deposits. Thus, though Ganesa Macula may have originated as a cryovolcanic
feature (or an impact crater, either of which would account for its
distinct circular outline), it appears to have been extensively modified
by both tectonic and fluvial processes.
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. NASA's 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 radar instrument was built by JPL and the Italian Space
Agency, working with team members from the United States and several
European countries.
For more information about the Cassini-Huygens mission, visit
http://saturn.jpl.nasa.gov/index.cfm.