The document describes the layers of Earth's atmosphere. It begins by stating that Earth's atmosphere is made up of a mixture of gases that surround the planet and protect life. It then provides details on the composition and properties of each of the four layers: the troposphere where weather occurs; the stratosphere which contains the ozone layer; the coldest mesosphere where meteors burn up; and the hottest thermosphere where the International Space Station orbits. Examples are given of phenomena associated with each layer like weather in the troposphere and auroras in the thermosphere.