Structure of the atmosphere

Structure of the atmosphere

Principal layers

Earth's atmosphere can be divided into five main layers. These layers are mainly determined by whether temperature increases or decreases with altitude. From highest to lowest, these layers are:

The outermost layer of Earth's atmosphere extends from the  upward. It is mainly composed of hydrogen and helium. The particles are so far apart that they can travel hundreds of kilometres without colliding with one another. Since the particles rarely collide, the atmosphere no longer behaves like a fluid. These free-moving particles follow ballistic trajectories and may migrate into and out of the or the 

 Temperature increases with height in the thermosphere from the mesopause up to the then is constant with height. The temperature of this layer can rise to 1,500 °C (2,730 °F), though the gas molecules are so far apart that  sense is not well defined. The orbits in this layer, between 320 and 380 km (200 and 240 mi). The top of the thermosphere is the bottom of the exosphere, called the  Its height varies with solar activity and ranges from about 350–800 km (220–500 mi; 1,100,000–2,600,000 ft).

The mesosphere extends from the stratopause to 80–85 km (50–53 mi; 260,000–280,000 ft). It is the layer where most  burn up upon entering the atmosphere. Temperature decreases with height in the mesosphere. The  the temperature minimum that marks the top of the mesosphere, is the coldest place on Earth and has an average temperature around −85  (−121 ; 188.1 Due to the cold temperature of the mesophere, water vapor is frozen, forming ice clouds (or A type of lightning referred to as either or  form many miles above thunderclouds in the troposphere.