The Earth's atmosphere is composed of different layers of gases that surround the planet. These layers are defined based on their temperature, pressure, and composition. From closest to the Earth's surface to farthest away, the layers of Earth's atmosphere are:
1. Troposphere: This layer extends from the Earth's surface up to an altitude of about 7-20 km, depending on the location. It contains the air that we breathe and is where most weather occurs. The temperature in this layer decreases with altitude.
2. Stratosphere: This layer extends from the top of the troposphere up to an altitude of about 50 km. It contains the ozone layer, which absorbs harmful ultraviolet radiation from the sun. The temperature in this layer increases with altitude.
3. Mesosphere: This layer extends from the top of the stratosphere up to an altitude of about 85 km. It is the coldest layer of the Earth's atmosphere, with temperatures decreasing with altitude.
4. Thermosphere: This layer extends from the top of the mesosphere up to an altitude of about 600 km. It is the hottest layer of the Earth's atmosphere, with temperatures increasing with altitude. It contains the ionosphere, where ions and free electrons are present and play a role in the reflection and transmission of radio waves.
5. Exosphere: This is the outermost layer of the Earth's atmosphere, extending from the top of the thermosphere to about 10,000 km above the Earth's surface. It gradually merges with the interplanetary medium and consists mainly of hydrogen and helium.