How High is the Atmosphere?

The atmosphere of Earth is a thin shell of air that remains in place due to gravity. As one moves away from the surface, the atmosphere becomes thinner and thinner, until the atmosphere is so thin that it gives way to the vacuum of space. Most of the atmosphere is below the height of 36 kilometers, and above 100 kilometers, it is nearly impossible to detect, but outer space is considered to be above 600 kilometers. There is more information about detecting and measuring atmosphere at