What Is the Thickest Layer of the Atmosphere?

The troposphere is the thickest layer of the atmosphere. It is the first of the five layers of the atmosphere, and it is just above the surface of the Earth. The troposphere contains 99% of the Earth’s water and 75% of its atmosphere.

The stratosphere is the second layer of the atmosphere. It is above the weather and very stable, and airplanes typically fly in this layer. The mesosphere lies above the stratosphere, and above that is the thermosphere. Auroras are formed in the thermosphere, and the International Space Station orbits in the layer. The exosphere is the final layer of the atmosphere.