exosphere

thumb|80px|right|Diagram showing the five primary layers of the Earth's atmosphere: exosphere, thermosphere, [[mesosphere, stratosphere, and troposphere. The layers are to scale. From the Earth's surface to the top of the stratosphere (50km) is just under 1% of Earth's radius.]]

AI overview

The exosphere is the outermost layer of Earth's atmosphere, as shown in the diagram of the five primary atmospheric layers. While the provided context doesn't detail its specific characteristics or importance, it represents the transition zone between Earth's atmosphere and outer space.

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Commons category: Exosphere

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Contents

Surface boundary exosphere
Earth's exosphere
Lower boundary
Upper boundary
Exosphere of other celestial bodies
The exosphere of Mercury
See also
References
Further reading

The exosphere (; ) 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 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. It is located directly above the thermosphere. Very little is known about it due to a lack of research. Mercury, the Moon, Ceres, Europa, and Ganymede have surface boundary exospheres, which are exospheres without a denser atmosphere underneath. The Earth's exosphere is mostly hydrogen and helium, with some heavier atoms and molecules near the base.