Question

Briefly explain main layers of the atmosphere.

Answer 1

Atmosphere is divided into five distinct layers or zones: troposphere, stratosphere, mesosphere, thermosphere (ionosphere) and exosphere.

Troposphere:

• It is the lowest region of the atmosphere which contains air and is subject to differential heating.
  
• It extends from the surface of Earth up to 8 to 20 km. The changes in the atmosphere resulting in the change of weather occurs in this layer.

Stratosphere:

• It extends to 30-35 miles above the earth’s surface.
  
• It contains much of the ozone in the atmosphere and the increase in temperature with height occurs because of absorption of ultraviolet (UV) radiation from the sun by this ozone.

Mesosphere:

• It lies above 30-50 miles from the earth surface.
  
• The air here is thin, and the molecules are a large distance apart.
  
• The mesosphere is the coldest atmospheric layer surrounding the earth.

Thermosphere:

• It rises several hundred miles from the earth surface and lies from 50-400 miles. Temperature in this layer can be as high as 2000 degree centigrade.
  
• The thermosphere is home to the International Space Station as it orbits Earth.

Exosphere:

• It extends from top of the thermosphere to 6200 miles. The layer contains very few atmospheric molecules which can escape into space.
  
• The air in the exosphere is very thin, and is made up mostly of helium, and hydrogen.