Earth's atmosphere
hideThe Earth's atmosphere is a layer of gases surrounding the planet Earth that is retained by the Earth's gravity. It has a mass of about five quadrillion metric tons. Dry air contains roughly (by volume) 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, and trace amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night.
There is no definite boundary between the atmosphere and outer space. It slowly becomes thinner and fades into space. An altitude of 120 km (75 mi) marks the boundary where atmospheric effects become noticeable during atmospheric reentry. The Kármán line, at 100 km (62 mi), is also frequently regarded as the boundary between atmosphere and outer space. Three quarters of the atmosphere's mass is within 11 km (6.8 mi; 36,000 ft) of the surface.
For more information about Earth's atmosphere, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with air
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(PhysOrg.com) -- Some plants have the ability to drastically reduce levels of indoor pollutants, according to new research at the University of Georgia. Researchers showed that certain species can effectively ...
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Nov 30, 2009 |
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The Naval Research Laboratory's Ion Tiger, a hydrogen-powered fuel cell unmanned air vehicle (UAV), has flown 26 hours and 1 minute carrying a 5-pound payload, setting another unofficial flight endurance record ...
Ohio school district sues over air pollution
Nov 28, 2009 |
5 / 5 (1) |
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(AP) -- A school district near Cincinnati is suing a plastics plant, accusing it of continuing to release chemicals in the air that exceed government safety standards.
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Dec 01, 2009 |
4 / 5 (1) |
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The first ever published study of aviation-related injuries and deaths in the U.S. finds that more than 1,013 patients are admitted to U.S. hospitals with aviation-related injuries annually, and that 753 aviation-deaths occur ...
Californians -- and their cell phones -- will help computer scientists monitor air pollution
Technology / Computer Sciences
17 hours ago |
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You want to go for a run, but you don't want to run in polluted air that might aggravate your asthma. University of California, San Diego computer scientists are creating a network of environmental sensors ...
