The atmosphere consists of 78% nitrogen, 21% oxygen, 1% water vapor, and a minute amount of other trace gases like argon, and carbon monoxide. All of these gases combine to absorb ultraviolet radiation from the Sun and warm the planet’s surface through heat retention. read more
The atmosphere just keeps getting less and less dense, until it "blends" into outer space. The atmosphere is divided into four layers based on temperature: the troposphere, stratosphere, mesosphere, and thermosphere. The Troposphere. This is the lowest layer of the atmosphere, closest to the surface of the earth. read more