Figure 13-21: Beneath Titan’s Clouds (a) This mosaic of Titan was constructed from Cassini images made at visible and infrared wavelengths during a close flyby in December 2005. (b) From 6.5 kilometers high, the descending Huygens lander recorded this view of features on Titan. Carved by flowing liquid, rivers and streams seem to have flowed between ridges about 200 meters high. It is too cold on Titan for water to be a liquid, so these streams and rivers must have carried liquid methane or ethane. (c) This nearly true-color Huygens image shows the view from Titan’s surface. The 15-cm (6-in.) wide “rock” is about 85 cm (33 in.) from the camera. Unlike Earth rocks, Titan “rocks” are chunks of water-ice.

(NASA/JPL/ESA/University of Arizona)