The atmosphere is a blanket of gases held in place by the gravitational pull of a planet, playing a critical role in sustaining life and regulating surface conditions. Its composition varies depending on the planet, but terrestrial atmospheres are primarily mixtures of nitrogen, oxygen, and argon, with trace amounts of other gases like carbon dioxide. Atmospheric layers, such as the troposphere and stratosphere, exhibit varying temperatures and chemical concentrations, influencing weather patterns and energy absorption. Functionally, the atmosphere protects planetary surfaces from harmful solar radiation, facilitates global heat distribution through atmospheric circulation, and provides the necessary elements for biological processes, making it a foundational component of the planetary system.