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
Hydrogen-Powered Ion Tiger Sets 26-hour Flight Endurance Record
9 hours ago |
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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 |
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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.
New climate targets may not change daily life much
Nov 27, 2009 |
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(AP) -- Americans' day-to-day lives won't change noticeably if President Barack Obama achieves his newly announced goal of slashing carbon dioxide pollution by one-sixth in the next decade, experts say.
Invading camels to be shot in Australian town
Nov 26, 2009 |
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(AP) -- Australian authorities plan to corral about 6,000 wild camels with helicopters and gun them down after they overran a small Outback town in search of water, trampling fences, smashing tanks and contaminating ...
Research reveals exactly how coughing is triggered by environmental irritants
Nov 23, 2009 |
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(PhysOrg.com) -- Scientists have revealed how environmental irritants such as air pollution and cigarette smoke cause people to cough, in research published today in the American Journal of Respiratory an ...
Barn personnel experience higher-than-average rates of respiratory symptoms
Nov 20, 2009 |
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The estimated 4.6 million Americans involved in the equine industry may be at risk of developing respiratory symptoms due to poor air quality in horse barns, according to a questionnaire study undertaken earlier this year ...
Braking news: Particles from car brakes harm lung cells
Nov 20, 2009 |
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Real-life particles released by car brake pads can harm lung cells in vitro. Researchers writing in BioMed Central's open access journal Particle and Fibre Toxicology found that heavy braking, as in an emergency stop, caused ...
Hidden threat: Elevated pollution levels near regional airports
Nov 18, 2009 |
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Scientists are reporting evidence that air pollution — a well-recognized problem at major airports — may pose an important but largely overlooked health concern for people living near smaller regional airports. ...
Glimpsing a greener future: Computer model foresees effects of alternative transportation fuels
Nov 16, 2009 |
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(PhysOrg.com) -- It's the year 2060, and 75 percent of drivers in the Greater Los Angeles area have hydrogen fuel cell vehicles that emit only water vapor.
Green heating and cooling technology turns carbon from eco-villain to hero
Nov 10, 2009 |
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Carbon is usually typecast as a villain in terms of the environment but researchers at the University of Warwick have devised a novel way to miniaturise a technology that will make carbon a key material in ...
Path to good health, less pollution is the sidewalk: report
Nov 09, 2009 |
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US pressure groups joined forces Monday to urge authorities to spend more to improve Americans' health and cut greenhouse gas emissions.
States call on EPA for tougher air pollution regulations
Nov 06, 2009 |
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Twelve states and the District of Columbia urged the Environmental Protection Agency Thursday to adopt more rigorous national policies so they can meet federal air pollution reduction requirements for the region.
Air pollution increases infants' risk of bronchiolitis
Nov 06, 2009 |
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Infants who are exposed to higher levels of air pollution are at increased risk for bronchiolitis, according to a new study.
Ford to put air bags into back seat belts of SUV (w/ Video)
Nov 05, 2009 |
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(AP) -- Air bags have long been mounted in the steering wheel, dashboard and sides of vehicles. Now, they're in the seat belts. Ford Motor Co. plans to introduce seat belt-mounted air bags in the back seat ...
Nocturnal wind maximum mapped for first time
Space & Earth / Earth Sciences
Nov 05, 2009 |
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On beautiful, sunny days with quiet weather conditions a strong wind develops in the evening at a height of about 200 metres.
