​Earth's Atmosphere Key Concepts

• ​The atmosphere is a mixture of gases surrounding the Earth. It is made of about 78% nitrogen, 21% oxygen, and 1% other gases, like carbon dioxide and argon.

• The atmosphere is important not only because it contains the air we breathe, but because its greenhouse effect also regulates the temperature of the Earth preventing it from becoming too hot or too cold to support life.

• ​Our atmosphere has five main layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

• The troposphere is where weather occurs, cycling water around the Earth.

• The stratosphere is where the ozone layer is found, which protects us from harmful ultraviolet radiation from the Sun. ​

• ​Most meteors burns up due to friction in the mesosphere.

• ​The International Space Station orbits the Earth in the thermosphere.