The bowl of windstuff

A Piece of Mars: Get out your red and cyan glasses to see an old crater, which fills this 0.775×0.7 km (0.48×0.43 mi) scene. The crater punched through many thin layers when it formed, some of which you can still see in around the rim. The crater is filled with many small dunes called transverse aeolian ridges (TARs), given this laborious and generic name because they aren’t quite like dunes we find on Earth and we don’t yet understand what they are. The TARs are common in this area, but there are even more here, where sand is swept into and then trapped inside this deep bowl. (HiRISE PSP_008735_1700_PSP_007878_1700, NASA/JPL/Univ. of Arizona)