This synthetic aperture radar image was obtained by the Cassini spacecraft
on its recent pass by Titan's south pole on Dec. 20, 2007.
This portion of the (T39) swath is of the region extending from about 84
degrees south to the south pole, with a length of approximately 760
kilometers (470 miles) and width of 150 to 170 kilometers (90 to 100
miles). The polar projection of this image is at 128 pixels per degree,
or approximately 351 meters per pixel (1,150 feet per pixel), and the
radar illumination is from the lower left with incidence angles from about
22 to 38 degrees.
This image covers the south pole of Titan, which can be seen as a region
of broad smooth valleys surrounded by rugged terrain. Also seen in this
image are two features interpreted as lakes, the larger of which may
correspond to dark features first identified by the imaging science
subsystem in June 2005 (See PIA06240). Their very dark appearance in
the radar image indicates that they are probably filled with liquid
methane. Other apparently empty lake basins are seen elsewhere in the
radar swath. Based on this swath, there appear to be fewer lakes near the
south pole than seen in a typical region near the north pole (for example,
see PIA10008). Since Titan is currently in
its late summer season in the southern hemisphere, this interpretation is
consistent with a previously proposed theory that methane fills the lakes
during the winter and evaporates during the summer, leaving them dry until
the next fall.
Intensity in this colorized image is proportional to how much radar
brightness is returned, or more specifically, the logarithm of the radar
backscatter cross-section. The colors are not a representation of what the
human eye would see. The lakes, darker than the surrounding terrain, are
emphasized here by tinting regions of low backscatter in blue.
Radar-brighter regions are shown in tan.
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/home/index.cfm.