The document describes the main layers of Earth's atmosphere. The thermosphere is the hottest layer due to absorption of solar heat. It is separated from space by the thermopause. The mesosphere is the coldest layer, reaching temperatures of -90 degrees Celsius. It is separated from the layers above and below by the mesopause and stratopause. The stratosphere contains strong winds beneficial for air travel and the ozone layer which absorbs UV radiation. The densest layer is the troposphere where temperature decreases with altitude and weather occurs. It is separated from the layers above by the tropopause.

4. THERMOSPHERE
The layer that is the hottest layer because of its
absorption of highly energetic solar heat.
Thermopause exist above the thermosphere that
also serves as a buffer zone which separates the
thermosphere from space.

5. Mesosphe
re
The layer above the stratosphere. The temperature
here reaches a minimum of -90 degrees celcius
and is considered to be the coldest.
Mesopause the thin buffer zone above the
mesosphere. This zone is actually the coldest.

6. Stratosphe
re
The air in this layer has strong, steady horizontal
winds which is advantageous to long distance
flights.
Stratopause a buffer zone that exist before the next
layer above the stratosphere.
The upper region is the ozone layer which contains
high concentration of ozone. The ozone layer plays
a very important role in absorbing the ultraviolet
radiation from the sun.

7. Troposphe
re
This layer is considered to be the densest among
other layers. Because temperature drops with
altitude, warm air on the surface of Earth rises
readily.
Tropopause a buffer zone above the troposphere
before the next layer.
Air molecules travel up and then back down
causing the formation of clouds eventually rain
from the moisture in the air. These variations give
rise to weather. Most jets and planes would fly
slightly above the troposphere to avoid turbulent.