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An atmosphere is a layer
of different gases that
surrounds a planet and
is held down by gravity.
The Earth's atmosphere
is mainly composed of
Nitrogen and Oxygen, and
provides the air that we
breathe and the wind that
blows in our face.
An Atmosphere
Some planets and moons are covered in a thin layer of gases. This is called an Atmosphere.
Not all atmospheres are the same. In fact, the Earth's atmosphere is the only one we have found that we can breathe.
Atmospheres are held down to the surface by gravity. This means that small planets and moons, which have tiny gravitational pulls, tend not to have them.
Although we cannot normally see our atmosphere, we can certainly feel it when we struggle to school on a windy day.
