Image data: NASA / JPL-Caltech / SSI / Image processing, stereo topography, and visualization were performed by Dr. Paul Schenk, Lunar and Planetary Institute, Houston
Iaptus' equatorial mountain ridge
One of the many surprises of Saturn's icy moon Iapetus is the prominent topographic ridge that straddles the equator like a walnut. The Cassini orbiter acquired a strip of color and stereo images along this ridge in September 2007, near the boundary between the dark and bright hemispheres. The origin of the ridge is unknown but Cassini's stereo data indicate the ridge at this site is broken into several sharp peaks 15 to 20 kilometers above the surrounding dark cratered plains. These are among the highest peaks in the Solar System. This perspective view looks southeast toward one of these peaks and is based on stereo topography derived from Cassini orbiter imaging data. Patches of bright pure water ice can be seen flanking these dark peaks, which have the brightness of soot. The scene is about 70 kilometers across and is excerpted from a movie showing a hypothetical flight over Iapetus.