Despite being trapped in the middle, the mesosphere is the coldest layer of Earth's atmosphere, with temperatures as low as -130F (-90C) at the very top of the mesosphere. This is because the ...

Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere.

mesosphere, thermosphere and exosphere (see graphic). Together, these layers protect us from the sun’s harmful radiation and keep temperatures on Earth habitable for all living beings.