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
Tiny Music Player Made from Wire Bridge (w/ Video)
Nov 04, 2009 |
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(PhysOrg.com) -- In 2008, scientists built a loudspeaker made of carbon nanotubes that produced sound and music based on the thermoacoustic effect. Now, a different team of scientists has built a loudspeaker ...
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 ...
Flying MAV Navigates Without GPS (w/ Video)
Nov 02, 2009 |
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(PhysOrg.com) -- During the last several years, researchers have been building micro air vehicles (MAVs) that can autonomously fly through different environments by relying on GPS for navigation. Recently, ...
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 ...
Robot Armada Might Scale New Worlds
Space & Earth / Space Exploration
Oct 28, 2009 |
4.3 / 5 (11) |
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(PhysOrg.com) -- An armada of robots may one day fly above the mountain tops of Saturn's moon Titan, cross its vast dunes and sail in its liquid lakes.
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 ...
Dyson Unveils His Bladeless Fan (w/ Videos)
Oct 14, 2009 |
3.9 / 5 (38) |
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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 ...
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 ...
Doing More with Your Cell Phone
Electronics / Consumer & Gadgets
Aug 10, 2009 |
4.5 / 5 (2) |
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(PhysOrg.com) -- As technology shrinks, and as it becomes possible to unplug and still conduct all of your business from a hand-held device, we demand more convenience. And there are two entities leading the ...
Swiss team unveil pioneering solar plane
Jun 26, 2009 |
4.7 / 5 (42) |
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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.
Trading energy for safety, bees extend legs to stay stable in wind
Jun 02, 2009 |
5 / 5 (3) |
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New research shows some bees brace themselves against wind and turbulence by extending their sturdy hind legs while flying. But this approach comes at a steep cost, increasing aerodynamic drag and the power ...
GOCE satellite achieves drag-free perfection (w/Videos)
Space & Earth / Space Exploration
May 26, 2009 |
4.8 / 5 (19) |
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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 ...
GPS satellites not 'falling out of the sky': Air Force
May 21, 2009 |
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You can put those maps away. The US Air Force has shot down fears that the space-based Global Positioning System (GPS) is going to crash.
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.
Report: Most Americans in areas with unhealthy air
Apr 29, 2009 |
4 / 5 (4) |
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(AP) -- Sixty percent of Americans live in areas with unhealthy air pollution levels, despite a growing green movement and more stringent laws aimed at improving air quality, the American Lung Association ...
