The exosphere (; from Ancient Greek ἔξω (éxō) 'outer, outside' and -sphere) is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is so low that, as in outer space, the molecules are essentially collision-less. In the case of bodies with substantial atmospheres, such as Earth's atmosphere, the exosphere is the uppermost layer, where the atmosphere thins out and merges with outer space.
The exosphere (; from Ancient Greek ἔξω (éxō) 'outer, outside' and -sphere) is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is so low that, as in outer space, the molecules are essentially collision-less. In the case of bodies with substantial atmospheres, such as Earth's atmosphere, the exosphere is the uppermost layer, where the atmosphere thins out and merges with outer space.
Source: Wikipedia "Exosphere" · CC BY-SA 4.0
Share this article: X · Bluesky