Exosphere: The exosphere is the upper layer of the atmosphere, where particles and gases escape to space. It is the last layer before space, though there is no clear boundary between this layer and outer space. It is sometimes simply called outer space. In this layer, particles are so far apart that they can travel hundreds of kilometers without colliding.

Thermosphere: In the thermosphere, temperature increases with height. This is the location of the beautiful Aurora Borealis that occurs in the night time sky at northern latitudes. The thermosphere is characterized by the presence of charged particles called ions causing the beautiful Aurora Borealis. It is also where the International Space Station (ISS) orbits.

Mesosphere: This layer is just above the stratosphere. In the mesosphere, temperature decreases with height. This is where meteors burn up when entering the atmosphere. This layer is the coldest place on Earth.

Stratosphere: Above the troposphere is the stratosphere. This layer is heated by the Sun’s UV rays and gets warmer as it goes higher. The stratosphere contains the ozone layer. Ozone molecules absorb high-energy UV from the Sun and make life on Earth possible. Without the protection of the ozone layer, too much radiation would reach Earth’s surface. Some human activities release chemical substances called CFC’s that can destroy the ozone layer.

Troposphere: The troposphere is the lowest level of the atmosphere and it is where all weather occurs on Earth. It is heated by heat that radiates from Earth’s surface. In the troposphere, temperature decreases as altitude increases.