On the surface of Titan

Caption ESA originale:"This raw image was returned yesterday, 14 January 2005, by ESA's Huygens probe during its successful descent to land on Titan. Sizes have been added to indicate scale of these features. Initially thought to be rocks or ice blocks, they are more pebble-sized. The two rock-like objects just below the middle of the image are about 15 cm (left) and 4 cm (centre) across respectively, at a distance of about 85 cm from Huygens. The surface is darker than originally expected, consisting of a mixture of water and hydrocarbon ice. There is also evidence of erosion at the base of these objects, indicating possible fluvial activity".