The mesosphere is a layer of Earth’s atmosphere above the stratosphere and thermosphere. It starts at about 50 km above the Earth’s surface and reaches as high as 85 km. Temperatures in this layer get colder the higher you get, with the highest point at -90 deg C or -130 deg F.
Approximately 1% of the Earth’s atmosphere is found in the mesosphere. Its temperature varies from 185 to 217 K, and its composition contains a variety of gases. The mesosphere also protects the Earth from asteroids and space debris. The mesosphere contains around 0.1 percent of Earth’s air mass, so most commercial aircraft only fly at lower levels.
Despite its importance, little is known about the mesosphere. Most meteors that enter the atmosphere are burned up in the mesosphere, which is much higher than the rest of the atmosphere. The mesosphere also contains a special type of cloud called a noctilucent cloud. Its odd lightning patterns can be seen dozens of miles above the clouds of the troposphere.
Scientists use sounding rockets to study the mesosphere. The mesosphere is the coldest part of the atmosphere. Temperatures can fall as low as -90 deg C (-130 deg F) at the top of the mesosphere. The mesosphere is largely composed of carbon dioxide, which helps keep the air cold.