Atmospheric Layers

Key Questions

  • Answer:

    A layer of ozone in the atmosphere that absorbs ultraviolet radiation.


    At the top of the troposphere (tropopause) is a form of oxygen that is unstable in the lower atmosphere, ozone or O3.

    Unlike the other gases of the atmosphere O3 absorbs ultraviolet radiation. This fact protects life on Earth from getting bombarded with ultraviolet radiation which is carcinogenic.

  • They vary, but not linearly, with distance from the earth. Excellent graphics can be found here:

  • Answer:

    See below.


    There are many layers of the atmosphere. There is a lot of difference in their properties.

    1. Troposphere - The lowest layer of the atmosphere is called troposphere. 'Tropo' means changing. Hence, Troposphere is that layer in which the temperature changes upward on account of convection current. Height - 16km at the equator and 7 km at the poles. It contains most the atmospheric air (75%).

    2. Stratosphere - Lies above Tropopause (the imaginary line between troposphere and stratosphere). The temperature in the lower part of this sphere does not change with altitude. The temperature is nearly constant upward about 20km and then increases, owing to absorption of ultraviolet radiation by ozone.

    3. Ionosphere - The ionosphere is defined as the layer of the Earth's atmosphere that is ionized by solar and cosmic radiation. It lies 75-1000 km (46-621 miles) above the Earth. Free electrons in this layer help in the conduction of electricity in this sphere.

    4. Mesosphere - The mesosphere starts at 50 km (31 miles) above Earth's surface and goes up to 85 km (53 miles) high. As you get higher up in the mesosphere, the temperature gets colder. The top of the mesosphere is the coldest part of Earth's atmosphere.

    5. Exosphere - The exosphere is the uppermost region of Earth's atmosphere as it gradually fades into the vacuum of space. Air in the exosphere is extremely thin - in many ways, it is almost the same as the airless void of outer space.