Forum - Mysterious Martian Gouges Carved By Sand-surfing Dry Ice
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Post 111287       December 15 '14 at 08:30 PM
By Soulskill from Slashdot's Iceman's-vacation-home department:
sciencehabit writes: After the Mars Reconnaissance Orbiter began beaming back close-up images of the Red Planet, researchers spotted peculiar features along the slopes of dunes: long, sharply defined grooves that seem to appear and disappear seasonally. They look like trails left behind by tumbling boulders, but rocks never appear in the sunken pits at the trail ends. Researchers initially took these gullies as signs of flowing liquid water, but a new model suggests they're the result of sand-surfing dry ice that breaks off from the crests of dunes and skids down slopes. This is no ordinary tumble — according to the model, the bases of the chunks are continually sublimating, resulting in a hovercraftlike motion that gouges the dune while propelling the ice down slopes.