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 upper atmosphere
Cassini Captures Ghostly Dance of Saturn's Northern Lights (w/ Video)
Space & Earth / Space Exploration
18 hours ago |
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(PhysOrg.com) -- In the first video showing the auroras above the northern latitudes of Saturn, Cassini has spotted the tallest known "northern lights" in the solar system, flickering in shape and brightness ...
'Ultra-primitive' particles found in comet dust
Space & Earth / Space Exploration
Nov 02, 2009 |
4.9 / 5 (9) |
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Dust samples collected by high-flying aircraft in the upper atmosphere have yielded an unexpectedly rich trove of relicts from the ancient cosmos, report scientists from the Carnegie Institution. The stratospheric ...
Solar winds triggered by magnetic fields
Nov 02, 2009 |
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(PhysOrg.com) -- Solar wind generated by the sun is probably driven by a process involving powerful magnetic fields, according to a new study led by UCL (University College London) researchers based on the ...
The Sun's Sneaky Variability
Space & Earth / Space Exploration
Oct 28, 2009 |
4.8 / 5 (11) |
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Every 11 years, the sun undergoes a furious upheaval. Dark sunspots burst forth from beneath the sun's surface. Explosions as powerful as a billion atomic bombs spark intense flares of high-energy radiation. ...
'Cosmic opera' set for Paris tower
Oct 08, 2009 |
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The rooftop of a Paris skyscraper is to be transformed into a cosmic-ray laboratory in an unusual week-long experiment due to start on Saturday.
EVE: Measuring the Sun's hidden variability
Space & Earth / Space Exploration
Sep 22, 2009 |
4.1 / 5 (7) |
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Every 11 years, the sun undergoes a furious upheaval. Dark sunspots burst forth from beneath the sun's surface. Explosions as powerful as a billion atomic bombs spark intense flares of high-energy radiation. ...
Scientists discover surprise in Earth's upper atmosphere
Space & Earth / Earth Sciences
Sep 10, 2009 |
4.6 / 5 (23) |
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(PhysOrg.com) -- UCLA atmospheric scientists have discovered a previously unknown basic mode of energy transfer from the solar wind to the Earth's magnetosphere. The research, federally funded by the National ...
Tropical storms endure over wet land, fizzle over dry
Space & Earth / Earth Sciences
Aug 26, 2009 |
5 / 5 (1) |
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(PhysOrg.com) -- If it has already rained, it's going to continue to pour, according to a Purdue University study of how ocean-origin storms behave when they come ashore.
New Images Indicate Object Hits Jupiter
Space & Earth / Space Exploration
Jul 21, 2009 |
4.9 / 5 (22) |
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(PhysOrg.com) -- Scientists have found evidence that another object has bombarded Jupiter, exactly 15 years after the first impacts by the comet Shoemaker-Levy 9.
Sir Richard Branson All Fired Up With Latest Rocket Motor Test
Space & Earth / Space Exploration
May 31, 2009 |
4.9 / 5 (15) |
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Virgin Galactic owned by Sir Richard Branson completed a successful test on May 28, 2009 of its hybrid nitrous oxide motor designed by Scaled Composites and a subcontractor Sierra Nevada Corporation. The ...
Fermi telescope explores high-energy 'space invaders'
May 04, 2009 |
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(Physorg.com) -- Since its launch last June, NASA's Fermi Gamma-ray Space Telescope has discovered a new class of pulsars, probed gamma-ray bursts and watched flaring jets in galaxies billions of light-years ...
The Surprising Shape of Solar Storms (w/Video)
Space & Earth / Space Exploration
Apr 14, 2009 |
4.8 / 5 (8) |
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(PhysOrg.com) -- Twin NASA spacecraft have provided scientists with their first view of the speed, trajectory, and three-dimensional shape of powerful explosions from the sun known as coronal mass ejections, ...
Obama looking at cooling air to fight warming
Apr 08, 2009 |
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(AP) -- Tinkering with Earth's climate to chill runaway global warming - a radical idea once dismissed out of hand - is being discussed by the White House as a potential emergency option, the president's ...
New Sun-Watching Instrument to Monitor Sunlight Fluctuations
Space & Earth / Space Exploration
Mar 23, 2009 |
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(PhysOrg.com) -- During the Maunder Minimum, a period of diminished solar activity between 1645 and 1715, sunspots were rare on the face of the sun, sometimes disappearing entirely for months to years. At ...
The lower atmosphere of Pluto revealed
Mar 02, 2009 |
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(PhysOrg.com) -- "With lots of methane in the atmosphere, it becomes clear why Pluto's atmosphere is so warm," says Emmanuel Lellouch, lead author of the paper reporting the results.
