Modeling Skylight and Aerial Perspective

Atmosphere Earth is enveloped by a vast amount of air called the atmosphere. It is relative thin compared to the size of the earth and fades away with increasing distance from the earth's surface. The earth's atmosphere is categorized into 4 layers troposphere, stratosphere, mesosphere and thermosphere. Troposphere where all the weather takes place and stratosphere, the two closest layers to earth's surface constitute more than 99% of the atmosphere. The troposphere and stratosphere extend up to 12 km and 53 km respectively from the earth's surface. The earth's atmosphere is composed of many gases. Nitrogen from decay of biological products constitutes 98% and Oxygen from photosynthesis constitutes 21% of the atmosphere. Gravity holds the atmosphere close to the earth's surface and explains why the density of the atmosphere decreases with altitude.