Radar image of dunes on Saturn’s moon Titan.
“These [ridges] are interpreted to be longitudinal dunes. Dunes are mostly an equatorial phenomenon on Titan, and the material forming them may be solid organic particles or ice coated with organic material. Spaced up to 3 kilometers (about 2 miles) apart, these dunes curve around bright features that may be high-standing topographic obstacles, in conformity with the wind patterns. The interaction between the two types of features is complex and not well understood, but clearly the topography and the dunes have influenced each other in other ways as well.”