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Post by moabiter on Jul 28, 2010 8:38:08 GMT -8
A Puzzling Collapse of Earth's Upper Atmosphere July 15, 2010 NASA-funded researchers are monitoring a big event in our planet's atmosphere. High above Earth's surface where the atmosphere meets space, a rarefied layer of gas called "the thermosphere" recently collapsed and now is rebounding again. "Something is going on that we do not understand," says Emmert. The thermosphere ranges in altitude from 90 km to 600+ km. It is a realm of meteors, auroras and satellites, which skim through the thermosphere as they circle Earth. It is also where solar radiation makes first contact with our planet. The thermosphere intercepts extreme ultraviolet (EUV) photons from the sun before they can reach the ground. When solar activity is high, solar EUV warms the thermosphere, causing it to puff up like a marshmallow held over a camp fire. (This heating can raise temperatures as high as 1400 Kāhence the name thermosphere.) When solar activity is low, the opposite happens. www.physorg.com/news198429352.html
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Post by clone on Nov 6, 2011 9:05:12 GMT -8
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