Atmosphere Part 2

Mesosphere :- 

• ​​Up to a height of about 80 km.
• In this, the temperature decrease with the height and falls to about 100° c at 80 km height.

​Ionosphere :-

•  It can be  Extends  up to about 85-640 km.
• It is also called Ionosphere because it contains electrically charged particles (ions) that reflects the radio waves back to the Earth surface thus making radio communication possible.
• Also protect Earth from harmful radiation that are comes from the sun. This causes increase in temperature with height in this layer.
• It also protect Earth from falling meteorites, as most of them burn out in this regions.

Exosphere :- 

• Here the Earth's gravity is extremely weak.
• Upper limit quite uncertain. The outer most part is called the Magnetosphere. The ionized particles increase in frequency with increasing in height. There are 2 belts in the upper atmosphere having a high concentration of ions particles. They are also known as Van Allen's Radiation belts. The inner belt lies about 2600 km from the Earth's surface, while the outer most part lies at about 13,000 to 19,000 km from it. These belts represent concentration of highly charged particles, protons and electrons from the sun, trapped within lines of forcrs of the Earth external magnetic field - the Magnetosphere.
• The final boundary between the Earth and the outer most space is called 'Magnetosphere'.

​NOTE :- 

• ​The auroras are produced by the charged paticles from the Sun Captured by earth's magnetic field at height of about 100 km. It may be visible as arcs of light or as colored certains, streamers of rays. 
• Auroras occurs in to the most frequently during the intense period of the 11 years sun spot cycle. In the Northern Hemispheres, they are called Aurora Borealis and in to the Southern Hemisphere as Aurora Australis.