This image of Titan's surface shows the entire scene obtained by the Cassini radar instrument on Sept. 7, 2006. It includes clear examples of the longitudinal dunes, as well as one of only three positively-identified impact craters (on the far left).

Titan's longitudinal dunes, first discovered during the third close flyby of Titan in February 2005 (see PIA03555), make up most of Titan's equatorial dark regions. These run east-west, are around 1 to 2 kilometers (0.6 to 1.2 miles) wide, spaced 1 to 2 kilometers apart, around 100 meters (111 yards) high, and from 10 to over 100 kilometers (6.2 to 62 miles) long. They curve around the bright features in the image -- which may be high-standing topographic obstacles -- following the prevailing wind pattern. Unlike Earth's silicate dunes, these may be solid organic particles or ice coated with organic material.

The left (western-most) portion of the image also shows one of only three impact craters confirmed on Titan so far. Roughly 30 kilometers (18.6 miles) in diameter, its center is at 70 degrees west, 10 degrees north. The difference in overall appearance between this crater, which has a central peak, and those without, such as Sinlap (see PIA07368), indicates variations in the conditions of impact, thickness of the crust, or properties of the meteorite that made the crater. The dark floor indicates smooth and/or highly absorbing materials.

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