Which two layers make up the thermosphere? Describe them in detail.
Answers
Thermosphere is the part of atmosphere that lies beyond the mesosphere.
It is made up of the ionosphere and the exosphere.
The ionosphere is the lower part of the thermosphere.
It lies above the mesopause.
It extends from 80 to 640 km.
Temperatures rise sharply here.
The ultraviolet radiations from the Sun break the gas molecules in this layer into electrically charged ions.
Therefore, the ionosphere is full of electrically charged ions, i.e., ions, which enable wireless transmission.
Radio waves transmitted from the Earth are reflected back to the Earth by these ions.
The upper limit of the ionosphere is called the ionopause.
The exosphere lies beyond the ionopause and is the uppermost layer of the thermosphere.
The upper limit of the exosphere is difficult to determine.
It merges with inter-planetary space.
The temperature here is estimated to be beyond 5500 degree Celsius.
The air is very thin here and its density is very low.
Only lighter gasses like helium and hydrogen are found here.
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