Related topics: nasa · climate change · solar wind · mars · solar radiation

Probing rare hot plasma flows in the upper atmosphere

Near Earth's poles, observers of the night sky often behold aurorae, colorful light shows in the upper atmosphere caused by interactions between the solar wind and our planet's magnetosphere. A little closer to the equator, ...

Do technological civilizations depend on atmospheric oxygen?

Nearly 2 million years ago a species of upright apes known as Homo erectus began to use fire. It was a gradual process, from opportunistic users of natural fires to masters able to craft flames from flint and tender. We are ...

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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.

This text uses material from Wikipedia, licensed under CC BY-SA