An atmosphere is a layer of gases that is held in place by the planet's gravity. It can vary greatly in composition, density, and temperature depending on the celestial body.
Here are some examples:
* Earth's atmosphere is primarily composed of nitrogen and oxygen, with smaller amounts of other gases like carbon dioxide and argon.
* Mars' atmosphere is much thinner and is mainly composed of carbon dioxide.
* Venus' atmosphere is extremely dense and hot, consisting mainly of carbon dioxide.
The atmosphere of a planet or other body plays a crucial role in its climate and weather patterns. It also protects the surface from harmful radiation from the sun and impacts from space objects.
