Mar 4, 2008

Defrosting Sand Dunes of Mars

Take a look at the picture of planet Mars. What are these strange shapes on the surface of Mars? They are actually defrosting sand dunes. As spring now dawns on the Northern Hemisphere of Mars, dunes of sand near the pole, as pictured above, are beginning to thaw.

The carbon dioxide and water ice actually sublime in the thin atmosphere directly to gas. Thinner regions of ice typically defrost first revealing sand whose darkness soaks in sunlight and accelerates the thaw. By summer, these spots will expand to encompass the entire dunes. The Martian North Pole is ringed by many similar fields of barchan sand dunes, whose strange, smooth arcs are shaped by persistent Martian winds. Credit: NASA


Related Posts Plugin for WordPress, Blogger...