In general, air pressure and density decrease with altitude in the atmosphere.However, temperature has a more complicated profile with altitude, and may remain relatively constant or even increase with altitude in some regions (see the temperature section, below).It extends from the mesopause (which separates it from the mesosphere) at an altitude of about 80 km (50 mi; 260,000 ft) up to the thermopause at an altitude range of 500–1000 km (310–620 mi; 1,600,000–3,300,000 ft).The height of the thermopause varies considerably due to changes in solar activity.
Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition.
The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space.
The Kármán line, at 100 km (62 mi), or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space.
Layers drawn to scale, objects within the layers are not to scale.
Aurorae shown here at the bottom of the thermosphere can actually form at any altitude in this atmospheric layer.
The exosphere contains most of the satellites orbiting Earth.