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
New climate targets may not change daily life much
Nov 27, 2009 |
3.5 / 5 (19) |
31
(AP) -- Americans' day-to-day lives won't change noticeably if President Barack Obama achieves his newly announced goal of slashing carbon dioxide pollution by one-sixth in the next decade, experts say.
Hydrogen-Powered Ion Tiger Sets 26-hour Flight Endurance Record
Nov 30, 2009 |
4.1 / 5 (7) |
1
The Naval Research Laboratory's Ion Tiger, a hydrogen-powered fuel cell unmanned air vehicle (UAV), has flown 26 hours and 1 minute carrying a 5-pound payload, setting another unofficial flight endurance record ...
More than 1,000 patients in US admitted annually for aviation-related injuries
Dec 01, 2009 |
4 / 5 (1) |
0
The first ever published study of aviation-related injuries and deaths in the U.S. finds that more than 1,013 patients are admitted to U.S. hospitals with aviation-related injuries annually, and that 753 aviation-deaths occur ...
Tiny Music Player Made from Wire Bridge (w/ Video)
Nov 04, 2009 |
4.2 / 5 (18) |
1
(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 ...
Ohio school district sues over air pollution
Nov 28, 2009 |
5 / 5 (1) |
0
(AP) -- A school district near Cincinnati is suing a plastics plant, accusing it of continuing to release chemicals in the air that exceed government safety standards.
Invading camels to be shot in Australian town
Nov 26, 2009 |
5 / 5 (1) |
0
(AP) -- Australian authorities plan to corral about 6,000 wild camels with helicopters and gun them down after they overran a small Outback town in search of water, trampling fences, smashing tanks and contaminating ...
Car That Runs on Compressed Air Questioned by Critics (w/ Video)
Nov 03, 2009 |
3.8 / 5 (21) |
38
(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 ...
Glimpsing a greener future: Computer model foresees effects of alternative transportation fuels
Nov 16, 2009 |
2.5 / 5 (4) |
1
(PhysOrg.com) -- It's the year 2060, and 75 percent of drivers in the Greater Los Angeles area have hydrogen fuel cell vehicles that emit only water vapor.
Research reveals exactly how coughing is triggered by environmental irritants
Nov 23, 2009 |
4 / 5 (1) |
0
(PhysOrg.com) -- Scientists have revealed how environmental irritants such as air pollution and cigarette smoke cause people to cough, in research published today in the American Journal of Respiratory an ...
New rechargeable zinc-air batteries coming soon
Oct 29, 2009 |
4.4 / 5 (45) |
15
(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 ...
Flying MAV Navigates Without GPS (w/ Video)
Nov 02, 2009 |
4.7 / 5 (12) |
1
(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, ...
Robot Armada Might Scale New Worlds
Space & Earth / Space Exploration
Oct 28, 2009 |
4.3 / 5 (11) |
5
(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 |
4.7 / 5 (28) |
35
(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 ...
Braking news: Particles from car brakes harm lung cells
Nov 20, 2009 |
5 / 5 (2) |
0
Real-life particles released by car brake pads can harm lung cells in vitro. Researchers writing in BioMed Central's open access journal Particle and Fibre Toxicology found that heavy braking, as in an emergency stop, caused ...
Dyson Unveils His Bladeless Fan (w/ Videos)
Oct 14, 2009 |
3.9 / 5 (38) |
25
(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 ...
