Exosphere: The exosphere is the outermost layer of Earth's atmosphere, where the air is extremely thin and merges into outer space. This layer mostly contains hydrogen and helium, and is where satellites orbit the Earth.
Thermosphere: The thermosphere lies below the exosphere and is characterized by a significant increase in temperature with altitude due to the absorption of high-energy solar radiation. This layer is also where the auroras occur and the International Space Station orbits.
Mesosphere: The mesosphere is located below the thermosphere and is where temperatures decrease with altitude, making it the coldest layer of the atmosphere. It protects Earth by burning up most meteoroids that enter from space.
Stratosphere: The stratosphere sits above the troposphere and contains the ozone layer, which absorbs harmful ultraviolet radiation from the Sun. In this layer, the temperature increases with altitude, providing stability and allowing aircraft to fly at high altitudes.
Troposphere: The troposphere is the lowest layer of the atmosphere, where we live and where weather occurs, extending from the Earth's surface up to about 8 to 15 kilometers high. In this layer, the temperature generally decreases with altitude, and it contains most of the atmosphere's mass and water vapor.