Question: what are the four main layers of the atmosphere?
Answer: Troposphere. The troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). ...  Stratosphere. The stratosphere starts just above the troposphere and extends to 50 kilometers (31 miles) high. ...  Mesosphere. ...  Thermosphere. ...  Ionosphere. ...  Exosphere. ...  Credit: NASA/Goddard.