Science Source Feb 2010
EN_90286391_0408
As spring dawns on the Northern Hemisphere of Mars, sand dunes near the pole, as pictured above, begin 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. The process might even involve sandy jets exploding through the thinning ice. By summer, 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.
2010-02-13
EAST NEWS
Science Source
NASA
bk0417
0,58MB
17cm x 12cm by 300dpi
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