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
Californians -- and their cell phones -- will help computer scientists monitor air pollution
Technology / Computer Sciences
Dec 04, 2009 |
1 / 5 (2) |
0
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 ...
Rocket launches Air Force satellite from Fla.
Space & Earth / Space Exploration
Dec 06, 2009 |
5 / 5 (1) |
0
(AP) -- A rocket carrying an Air Force satellite that will be used by the military has launched from Cape Canaveral.
Search results for air
Oceans' Uptake of Manmade Carbon May Be Slowing
Space & Earth / Earth Sciences
13 hours ago |
3.6 / 5 (15) |
4
(PhysOrg.com) -- The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Now, the first year-by-year accounting of this mechanism ...
NASA's WISE Set to Blast Off and Map the Skies
Space & Earth / Space Exploration
14 hours ago |
5 / 5 (2) |
0
(PhysOrg.com) -- The countdown clock is ticking, with just days to go before the Wide-field Infrared Survey Explorer, or WISE, rockets into space on a mission to map the entire sky in infrared light.
Microscopic gyroscopes, the key for motion sensing
16 hours ago |
5 / 5 (4) |
0
(PhysOrg.com) -- Tiny devices made possible by combining the latest advances in mechanical and electronics technology could be at the heart of next-generation personal navigation and vehicle stabilisation ...
Interactive digital art show opens in London
17 hours ago |
not rated yet |
0
The creative side of information technology went on display in London this week, in an arresting new interactive show including glowing reeds and a blinking mechanical eye.
Energy efficiency technologies offer major savings
17 hours ago |
4 / 5 (2) |
0
Energy efficiency technologies that exist today or that are likely to be developed in the near future could save considerable money as well as energy, says a new report from the National Research Council. Fully adopting ...
EPA head: US must make up for lost time on climate
23 hours ago |
2.3 / 5 (6) |
3
(AP) -- The top U.S. environmental official told a divided U.N. climate conference Wednesday that the Obama administration's moves to "make up for lost time" and cut greenhouse gases would complement congressional ...
Don't Blame Cows for Climate Change
Dec 08, 2009 |
3.3 / 5 (9) |
4
(PhysOrg.com) -- Despite oft-repeated claims by sources ranging from the United Nations to music star Paul McCartney, it is simply not true that consuming less meat and dairy products will help stop climate ...
A special kind of flight training
Dec 08, 2009 |
4 / 5 (2) |
0
(PhysOrg.com) -- A new generation of flight simulators will attempt to make air traffic safer.
Prof gets messages from space
Space & Earth / Space Exploration
Dec 08, 2009 |
4.3 / 5 (6) |
0
(PhysOrg.com) -- Barbara Frisken received several messages from outer space this year on her answering machine.
Treating cluster headaches with high-flow oxygen appears effective
Medicine & Health / Neuroscience
Dec 08, 2009 |
not rated yet |
0
Patients with a cluster headache, which is characterized by bouts of excruciating pain usually near the eye or temple, were more likely to report being pain-free within 15 minutes of treatment with high-flow oxygen than patients ...
List of search results for air
