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 earths atmosphere
Scientists pinpoint the 'edge of space'
Space & Earth / Earth Sciences
Apr 09, 2009 |
4.7 / 5 (14) |
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Where does space begin? Scientists at the University of Calgary have created a new instrument that is able to track the transition between the relatively gentle winds of Earth's atmosphere and the more violent flows of charged ...
Boulder-sized Asteroid Will Burn Up in Earth's Atmosphere Tonight
Space & Earth / Space Exploration
Oct 07, 2008 |
4.4 / 5 (11) |
2
(PhysOrg.com) -- A tiny asteroid discovered just hours ago at an Arizona observatory will enter Earth's atmosphere harmlessly at approximately 10:46 p.m. Eastern time tonight (2:46 a.m. Greenwich Mean Time). ...
Team Finds Riches in Meteorite Treasure Hunt
Space & Earth / Space Exploration
Mar 31, 2009 |
4.9 / 5 (9) |
1
(PhysOrg.com) -- Just before dawn on Oct. 7, 2008, an SUV-sized asteroid entered Earth's atmosphere and exploded harmlessly over the Nubian Desert of northern Sudan. Scientists expected the asteroid, called ...
The MAGIC-II Telescope is ready to team up
Apr 15, 2009 |
4.5 / 5 (2) |
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(PhysOrg.com) -- Together with the MAGIC-I telescope, MAGIC-2 allows stereoscopic observations using these two largest gamma-ray telescopes. Astronomers can explore sources of very-high energy gamma rays. ...
Moon magic: Researchers develop new tool to visualize past, future lunar eclipses
Space & Earth / Space Exploration
Jun 08, 2009 |
4 / 5 (2) |
0
Lunar eclipses are well-documented throughout human history. The rare and breathtaking phenomena, which occur when the moon passes into the Earth's shadow and seemingly changes shape, color, or disappears ...
