Thermosphere vs. Mesosphere — What's the Difference?

The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the thermosphere thus constitutes the larger part of the ionosphere.

The mesosphere (; from Greek mesos, "middle") is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere. In the mesosphere, temperature decreases as altitude increases.

The outermost layer of the atmosphere, between the mesosphere and interplanetary space, where air becomes extremely thin and temperatures increase steadily with altitude.

The portion of the atmosphere from about 50 to 100 kilometers (31 to 62 miles) above the surface of the earth, characterized by temperatures that decrease from 10°C to -96°C (50°F to -140°F) with increasing altitude.

The layer of the Earth's atmosphere directly above the mesosphere and directly below the exosphere.

(meteorology) The layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere.

The atmospheric layer between the mesosphere and the exosphere

(geology) The part of the Earth's mantle below the asthenosphere and above the outer core.

The atmospheric layer between the stratosphere and the thermosphere