The dunes of Titan
Titan has sand dunes. Gigantic stygian dunes of black, hydrocarbon sand cover most of Titan’s equatorial regions, and new data from the Cassini orbiter not only shows how vast the dune fields are, they show which direction the dunes are facing. Titan’s gravity is weak and it’s atmosphere is thick, compared with Earth, so it’s easy on this massive moon of Saturn to entrain tiny grains of sand into the wind and carry them across wide distances.
On Titan the equatorial region is decorated by endless twisting, wandering dunes that constantly shift as brisk westerly winds scour the ground. According to Cassini data the dunes are mostly hydrocarbon material… organic matter, frozen solid into abrasive grains of hard sand under Titan’s thick, frigid atmosphere of nitrogen. Part of the dune material is also probably ice sand… water ice so cold it is as hard as rock, weathered to grit from a landscape and surface composed almost entirely of hard, glittering water ice. At higher latitudes Titan is wetter, with lakes and rivers… which flow with liquid methane instead of water. But in the equatorial desert lowlands, black storms of frozen oil howl in the icy night.