This radar image, obtained by Cassini's radar instrument during a
near-polar flyby on Sept. 23, 2006, is the second scene that shows clear
shorelines reminiscent of terrestrial lakes.
With Titan's colder temperatures and hydrocarbon-rich atmosphere, these
lakes most likely contain a combination of methane and ethane (both
hydrocarbons), not water. This high-latitude opportunity confirmed
scientists' predictions that lakes would be present here, consistent with
calculations that suggested that hydrocarbons would be stable as liquids
at the colder, high latitudes. It also showed unusual complex terrain, the
origin of which remains a mystery.
The image is illuminated by the radar from the top, and shows features as
small as about 300 meters (980 feet). Starting at the left (63 degrees
north latitude by 255 degrees west longitude), where the terrain appears
bland and dark, the swath heads northeast into a more rugged, mottled
terrain, probably containing dried lakes and canyons formed by the
presence of liquid hydrocarbons.
The first lake, an irregular, almost-triangular shape about 16 kilometers
(10 miles) across at the widest point, can be seen near the bottom of the
image; it appears to be fed by two channels from the south. Several more
lakes can be seen about one-third of the way into the swath, near the
closest approach to the pole, (north of 75 degrees north latitude),
including Titan's "kissing lakes" (see PIA08740), each 20 to 25 kilometers
(12 to 16 miles) across. Two other lakes feature narrow or angular bays,
including a broad peninsula that on Earth would be evidence that the
surrounding terrain is higher and confines the liquid. Continuing on,
about three-quarters of the way through the swath, the terrain becomes
brighter and more rugged, again indicating possible dried lakes and
canyon-like structures. A long 100-kilometer (60-mile) series of grooves
appears, likely carved by liquids. Next is an area of bright terrain with
an unusual directional texture, indicating possible dunes, but brighter
and perhaps different in nature than those seen elsewhere. Finally,
towards the end of the swath, where the image quality is poorest, the
terrain becomes mottled and difficult to interpret.
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 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.
