Quiet Sun leads to upper atmosphere collapse | COSMOS magazine

Quiet Sun leads to upper atmosphere collapse | COSMOS magazine: "WASHINGTON: The upper reaches of Earth's atmosphere are unexpectedly shrinking and cooling due to lower ultraviolet radiation from the Sun, U.S. scientists said.

The Sun's energy output dropped to unusually low levels from 2007 to 2009, a significantly long spell with virtually no sunspots or solar storms, according to scientists from the National Center for Atmospheric Research in Boulder, Colorado.

During that period, the thermosphere, whose altitude ranges from about 90 to 500 kilometers, shrank and contracted from the sharp drop in ultraviolet radiation, said the study published in Geophysical Research Letters."