Far Out
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Earth’s Atmosphere Extends Past Moon
The scientific boundary between Earth’s atmosphere and space is the Kármán line, 62 miles high. But a team of astronomers have published evidence in the Journal of Geophysical Research: Space Physics that the geocorona, a tenuous cloud of neutral hydrogen in the outermost region of the Earth’s atmosphere that glows in far-ultraviolet light, extends much farther than the moon. The discovery means that telescopes positioned in the geocorona will need to have some of their settings adjusted for deep-space observations.
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