The atmosphere is the body of air which surrounds our planet. Most of our atmosphere is located close to the earth's surface where it is most dense. The air of our planet is 78% nitrogen and just under 21% oxygen; the small amount remaining is composed of carbon dioxide and other gasses.It is a mixture of gases encircling the Earth and held by the Earth’s gravity. This invisible mixture of nitrogen, oxygen, argon, carbon dioxide, and water vapor protects the planet from harmful radiation and makes life on it. (Atienza et al., 2012)
Atmosphere and Ecology
The atmosphere implies the protective blanket of gases, surrounding the earth: (a) It sustains life on the earth.
(b) It saves it from the hostile environment of outer space. (c) It absorbs most of the cosmic rays from outer space and a major portion of the electromagnetic radiation from the sun. (d) It transmits only here ultraviolet, visible, near infrared radiation (300 to 2500nm) and radio waves (0.14 to 40 m) while filtering out tissue-damaging ultraviolet waves below about 300 nm. (Singh, 2006)
Oxidizing atmosphere - Current atmosphere
Reducing atmosphere - Original atmosphere. In particular, it probably did not contain oxygen.
Composition of the Atmosphere
The oxygen so characteristic of our atmosphere was almost all produced by plants (cyanobacteria or, more colloquially, blue-green algae).Nitrogen makes up 78 percent of the Earth’s atmosphere. It enters the atmosphere when volcanoes erupt and when dead plants and animals decay. Oxygen, the second most abundant gas in Earth’s atmosphere, is primarily produced by plants.Gases including argon, carbon dioxide, methane, and water vapor make up the rest of the atmosphere.In addition to gases, the atmosphere contains many types of tiny, solid particles, or atmospheric dust. Atmospheric dust is mainly soil but includes salt, ash from fires, volcanic ash, particulate matter from combustion, skin, hair, bits of clothing, pollen,...
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