The two most abundant gases in the Earth’s atmosphere are nitrogen and oxygen. The atmosphere contains approximately 78 percent nitrogen and about 21 percent oxygen. The Earth’s atmosphere also contains lesser amounts of other gases, such as argon, carbon dioxide, hydrogen and neon.
The atmosphere is made up of gas layers that surround the Earth. These layers of gases protect or insulate the planet from getting too cold or hot. Likewise, the ozone layer, a region of the stratosphere, protects the planet from radiation that comes from the sun.
Earth’s atmosphere consist of five layers: the troposphere, stratosphere, mesosphere, thermosphere and exosphere. The closest layer to the Earth’s surface is the troposphere, and the exosphere is the furthest away.