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
EPA closer to global warming warning (Update)
Mar 23, 2009 |
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(AP) -- The Environmental Protection Agency has taken the first step on the long road to regulating greenhouse gases under the Clean Air Act.
Climate trouble may be bubbling up in far north
Aug 30, 2009 |
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(AP) -- Only a squawk from a sandhill crane broke the Arctic silence - and a low gurgle of bubbles, a watery whisper of trouble repeated in countless spots around the polar world.
New rechargeable zinc-air batteries coming soon
Oct 29, 2009 |
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(PhysOrg.com) -- A new breed of rechargeable zinc-air batteries is soon to be available, and may replace lithium-ion batteries in cell phones, laptops and other consumer items. Lithium-ion batteries store ...
Swiss team unveil pioneering solar plane
Jun 26, 2009 |
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Round-the-world balloooning pioneer Bertrand Piccard unveiled his solar-powered aircraft in Switzerland on Friday, ready for another trend-setting circumnavigation of the globe powered solely by the sun.
Dyson Unveils His Bladeless Fan (w/ Videos)
Oct 14, 2009 |
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(PhysOrg.com) -- James Dyson, inventor of the bag-less vacuum cleaners has taken his invention one step further with the unveiling of the bladeless fan. Using 'Air Multiplier' technology the bladeless fan ...
Cyborg beetles to be the US military's latest weapon (w/ Video)
Oct 15, 2009 |
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(PhysOrg.com) -- A team of scientists funded by the US Defense Advanced Research Projects Agency (DARPA) have implanted miniature neural and muscle stimulation systems into beetles to enable their flight to ...
New plan to reduce planes' CO2 emissions
Mar 31, 2009 |
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(AP) -- Aviation groups in Europe announced a plan Tuesday to change the way commercial planes land in order to reduce their global-warming emissions of carbon dioxide.
World's largest telescope to be built in Hawaii
Jul 22, 2009 |
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(AP) -- Hawaii was chosen Tuesday as the site for the world's biggest telescope, a device so powerful that it will allow scientists to see some 13 billion light years away and get a glimpse into the early ...
GOCE satellite achieves drag-free perfection (w/Videos)
Space & Earth / Space Exploration
May 26, 2009 |
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(PhysOrg.com) -- ESA's gravity mission GOCE has achieved a first in the history of satellite technology. The sophisticated electric propulsion system has shown that it is able to keep the satellite completely ...
Color-changing roof tiles absorb heat in winter, reflect it in summer
Oct 08, 2009 |
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(PhysOrg.com) -- Anyone who has ever stepped barefoot onto blacktop pavement on a hot sunny day knows the phenomenon very well: Black surfaces absorb the sun's heat very efficiently, producing a toe-scorching ...
Mystery Source of Solar Wind Heating Identified
Jul 17, 2009 |
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(PhysOrg.com) -- The solar wind is hotter than it should be, and for decades researchers have puzzled over the unknown source of energy that heats it. In a paper published in the June 12 issue of Physical Re ...
Researchers closer to the ultimate green 'fridge magnet'
May 15, 2009 |
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(PhysOrg.com) -- Scientists are a step closer to making environmentally-friendly 'magnetic' refrigerators and air conditioning systems a reality, thanks to new research published today in Advanced Materials.
Car That Runs on Compressed Air Questioned by Critics (w/ Video)
Nov 03, 2009 |
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(PhysOrg.com) -- As electric cars begin breaking into the short-distance vehicle market, one French company thinks that it has an alternative to the electric vehicle: a car that runs on compressed air. Motor ...
Drinking water from air humidity
Jun 05, 2009 |
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Cracks permeate the dried-out desert ground, the landscape bears testimony to the lack of water. But even here, where there are no lakes, rivers or groundwater, considerable quantities of water are stored ...
Clean fuels could reduce deaths from ship smokestacks by 40,000 annually
Jul 08, 2009 |
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Rising levels of smokestack emissions from oceangoing ships will cause an estimated 87,000 deaths worldwide each year by 2012 -- almost one-third higher than previously believed, according to the second major ...
