Related topics: air pollution · air quality · pollution

NASA's AIRS images Tropical Storm Barry before landfall

NASA's Atmospheric Infrared Sounder (AIRS), aboard the Aqua satellite, captured imagery of Tropical Storm Barry in the Gulf of Mexico at about 2 p.m. local time on Friday afternoon. According to the National Hurricane Center, ...

Dramatic warming projected in world's major cities by 2050

By the year 2050, London's climate will resemble Madrid's today; Paris will be more like Canberra; Stockholm like Budapest and Moscow like Sofia, according to a new analysis published Wednesday that relied on optimistic projections.

Lovebirds ace maneuvers in the dark

While pilots rely on radio signals, advanced computations and tools to keep them on course during strong crosswinds, birds can naturally navigate these demanding conditions—and do so in environments with little visibility. ...

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Earth's atmosphere

The 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.

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