Earths atmosphere is made up of a mixture of nitrogen (78%), oxygen (21%), and other gases (1%). There are 5 layers to the Earths atmosphere: Exosphere: 700 to 10,000 km, Thermosphere: 80 to 700 km, Mesosphere: 50 to 80 km, Stratosphere: 12 to 50 km, Troposphere: 0 to 12 km.The atmosphere becomes thinner until it gradually reaches space.