Dizzying Dunes

Credit: NASA/JPL/University of Arizona

Any­one who has spent time at a swim­ming pool has seen some­thing like this image. It looks like shad­ows on the bot­tom of a pool from rip­ples on the sur­face. But wind, instead of water, is involved in mak­ing this dizzy­ing pat­tern of dunes on Mars.

Explore the image from NASA’s HiRISE cam­era aboard the Mars Recon­nais­sance Orbiter of sand dunes in Olympia Undae on Mars. Olympia Undae forms a vast sea of sand sur­round­ing the Mar­t­ian north pole. Zoom in closer and tiny rip­ples and grooves appear. These fea­tures are formed by wind blow­ing from a con­stant direc­tion as well as the larger dunes.

We find pat­terns of sand dunes like this on Earth but what excites sci­en­tists more is what makes up the dunes. Gyp­sum is a light-colored, chalky, whitish min­eral. Gyp­sum forms in the pres­ence of liq­uid water and these dunes are full of the min­eral. Sci­en­tists are work­ing to track down the source of the min­eral and when in Mars’ wet­ter past it formed.