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

The Sun is less active magnetically than other stars

Our sun is the source of life on Earth. Its calm glow across billions of years has allowed life to evolve and flourish. This does not mean the sun doesn't have an active side. We have observed massive solar flares, such as ...

What makes Saturn's atmosphere so hot

The upper layers in the atmospheres of gas giants—Saturn, Jupiter, Uranus and Neptune—are hot, just like Earth's. But unlike Earth, the Sun is too far from these outer planets to account for the high temperatures. Their ...

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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