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The
atmosphere is like a blanket of the Earth. It
contains many layers. The thickness of the atmosphere
is relatively thin compared to the size of the Earth.
The
major and significant layers of the atmosphere are:

The last layer in our
atmosphere is the exosphere which extends
out to 960 km from sea level. This layer
consists of a variety of very small
quantities of gases including helium,
nitrogen, oxygen and argon. Temperatures
here can range from 300 ºC to 1650 ºC.
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Temperatures in here rise
dramatically to about 1480 °C under
certain conditions. Among the importance
of the thermosphere is in long range
radio broadcasting and protection from
meteors and obsolete satellites because
the high temperatures burn up nearly all
the debris coming toward earth. This is
because the thermosphere contains charged
particles or ions which have the ability
to reflect radio waves back to Earth.
The thermosphere can be as
high as 120 km.
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The mesosphere extends to
about 80 km from the Earth. In here the
temperature decreases again. Temperatures
stop decreasing at the mesopause which is
in between the mesosphere and the next
layer, the thermosphere.
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The stratosphere extends
to about 50 km from the Earth's surface.
Temperatures increase to 4 °C. At about
24 km above earth, lies the ozone layer
which absorbs a large amount of the Sun's
ultraviolet.
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This layer
extends from ground level to between 8 to
16 km high from the sea level. The height
of the troposphere at the equator is the
highest due to the amount of solar energy
reaching earth. The lowest, at the two
poles.
This is because
warm air expands more compared to cold
air.
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Temperature drops 1 °C
every 165 m. The level at which
temperature stops decreasing is called
the tropopause. Temperatures there can be
as low as -58 °C.
It is in this level where
what we call weather occurs.
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The proportion of gases in the
troposphere:
| Nitrogen |
78% |
| Oxygen |
21% |
| Carbon Dioxide and Noble Gases |
01% |
The above
table can be a bit inaccurate sometimes as
proportions of gases in different areas of Earth
differ.
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| Weather
balloons used to research weather in the
upper layers of the atmosphere |
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