Geography

Lecture on the Atmosphere

Lecture on the Atmosphere

The Earth is surrounded by a blanket of air, which we call the atmosphere. The atmosphere consists of four unique layers (the troposphere, the stratosphere, the mesosphere, and the thermosphere). The atmosphere reaches over 560 kilometers (348 miles) up from the surface of the Earth. The atmosphere is primarily composed of nitrogen (about 78%) and oxygen (about 21%). Other components exist in small quantities.