2016年6月7日 星期二

Frosted Dunes on Mars


Sand dunes cover much of this terrain, which has large boulders lying on flat areas between the dunes. It is late winter in the southern hemisphere of Mars, and these dunes are just getting enough sunlight to start defrosting their seasonal cover of carbon dioxide. Spots form where pressurized carbon dioxide gas escapes to the surface. via NASA http://ift.tt/1VKpWxN

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