How many layers of atmosphere are there?

The atmosphere of Earth is consisted on gas layers covering the earth completely. Atmosphere is retaining by Earth’s gravity. The atmosphere is vital because it is saving the life on earth. There are many duties of atmosphere like breathing, absorbing ultraviolet solar radiation and warming the surface. Atmospheric science is the profession over atmosphere events. It includes 78.09% nitrogen, 20.95% oxygen, 0.93% argon and 0.039% carbon dioxide. There are also some small amounts of different gases. Also it includes water vapor which rises from earth. Atmosphere consists on layers. There are principal layers and other layers in it. How many layers of atmosphere are there?


There are 5 principal layers and some other layers of atmosphere. They are Exosphere, Thermosphere, Mesosphere, Stratosphere, Troposphere.
Exosphere is a thin and includes lightest atmospheric gases in it. Main gases in exosphere are hydrogen, carbon dioxide, helium and atomic oxygen. In the earth’s atmosphere, Exosphere is latest part of atmosphere and many scientists believe that there’s no clear boundary dividing space and exosphere. In some scientific works, Exosphere is putting as a part of outer space.
Thermosphere is the layer of atmosphere under exosphere and above mesosphere. Thermosphere is an important layer of atmosphere because ultraviolet radiation causes ionization in this layer. According to calculations, it’s 85 kilometres high from earth. It absorbs highly energetic solar radiation. Because of solar activity, temperature can rise up to 2000 °C. It’s also an important layer for broadcasting world because because of this layer’s electrically charged internal environment, radio waves’ bounce off process is becoming possible and radio signals are receiving beyond the horizon. Also Auroras occur in this layer.

Mesosphere is below the thermosphere and above the stratosphere. In this layer, temperature decreases directly. Upper part of Mesosphere is the naturally coldest part of earth with −143 °C. Average height of Mesosphere is 50 kilometers from earth surface. Top bound of Mesosphere is 100 kilometers from earth surface. Mesosphere has very important duties but most important one is melting the meteors. Nearly 40 tons of meteoroids enters the atmosphere per year and most of them melt on the Mesosphere. Because of vaporizing the meteoroids, there is a big resource for higher concentration of iron in this layer.
The stratosphere is one of the biggest layers of earth’s atmosphere. It’s below the mesosphere and above the troposphere. There are many temperature layers on stratosphere. The Stratosphere is 10–13 km high from earth surface. Temperature increases in every sublayer of Stratosphere but hottest point of layer is −3°C which is below freezing point of water. It’s the most secure atmosphere layer for commercial airliners. They mostly use 9–12 km which is in the boundaries of The stratosphere. Temperate latitudes in this layer optimize fuel burn.

Also in turbulence situations, many pilots prefer to go Stratosphere. There are many researches about bacterial life in the stratosphere. According to latest researches, bacterial life is possible in this layer. So it’s a part of biosphere. Also some birds are reported to fly on the bottom levels of The stratosphere. It was a popular science news that a Rüppell’s Vulture entered a jet engine while flying on the bottom part of The stratosphere in 70s.
Troposphere is the lowest part of atmosphere. Water vapor and aerosols are the main ingredients of Troposphere. It’s 17 km far from earth averagely. Troposphere has a different behavior and structure than other layers so many differences on day-to-day weather occurs in this layer. Pressure differs on layers of Troposphere, it’s lower in sea level and higher in upper layers.