Labels:bulletin board | hakham | monitor | rock | sky | windowpane OCR: ATMOSPHERE Exosphere 500 km Composition The Earth's atmosphere today is thought to be the result of volcanic activity and the presence of living organisms which produce oxygen through photosynthesis. Between sea level and an altitude Of about 10 km lies the troposphere which consists mainly 01 nitrogen (78%) and oxygen (21 %) with traces 01 water vapor, argon, and carbon dioxide This region contains 80% of the Earth' atmosphere (by mass) and where virtually all recognizable weather Thermosphere takes place. bove the troposphere lies the 80 km stratosphere, where layer of ozone absorbs ultraviolet radiation from the Sun. In the thermosphere which begins about 80 km from the surface, the molecules are heated by radiation from Stratosphere the Sun, and the temperature increases with 10 km inc ...
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