Larger and larger lakes, islands and dunes on Titan
During a near-polar flyby on 22 February 2007, Cassini's radar instrument took beautiful images of Titan's surface features – a big island smack in the middle of one of the larger lakes imaged on this moon so far, and dunes.
The island visible in the first radar image is about 90 by 150 kilometres across, about the size of the Big Island of Hawaii. It may actually be a peninsula connected by a bridge to a larger stretch of land. As you go farther down the image, several very small lakes begin to appear, which may be controlled by local topography.
The view is centred at about 79°N latitude and 310°W longitude (north is toward the left of this image), offering further evidence that the largest lakes are at the highest latitudes.
The second radar image shown in this article, also obtained by Cassini's radar on 22 February 2007, shows dunes surrounding a bright feature on Saturn's moon Titan.
Dunes have been previously seen on Titan, so far concentrated near the equator. They are thought to be composed of small hydrocarbon or water ice particles - probably about 250 microns in diameter, similar to sand grains on Earth. These are formed into dunes by the prevailing west-to-east surface winds. Because of the shape and length of the dunes, they are probably 'longitudinal' (lying in the same direction as the average wind) rather than transverse dunes, which form across the wind and are more common on Earth.
There are several kinds of interaction between the dunes and the brighter features in this image. At the left, the dunes seem to be covering the bright material, while at the centre and right, they seem to be terminated against it. At the lower centre and lower right, they flow around it. These various interactions will help scientists to determine the nature of both of these features.
The image is centred at about 3.5°S latitude and 37.3°W longitude (north is toward the left of the image).
Note for editors
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. 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
Jean-Pierre Lebreton, ESA Huygens Project Scientist
Email : jean-pierre.lebreton @ esa.int