The outer shell in the atmosphere (at c.400 km/250 mi) from which light gases can escape.
The exosphere is the uppermost layer of the atmosphere.
The atmosphere in this layer is sufficiently rarefied for satellites to orbit the Earth, although they still receive some atmospheric drag.
Exobase, also called the critical level, the lowest altitude of the exosphere, is defined in one of two ways:
The height above which there are negligible atmospheric collisions between the particles and The height above which the constituent atoms are on purely ballistic trajectories.|
Earth's atmosphere |
|
|
|
|
|
|
User Comments Add a comment…