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, ...
Planetary Sciences
Sep 11, 2023
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The first hours after a fireball sighting are like a detective mystery. Last night around midnight, people across Melbourne took to social media to report sightings of a bright light slowly streaking across the sky.
Planetary Sciences
Aug 8, 2023
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43
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 ...
Astrobiology
Aug 7, 2023
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8
This summer has seen a violent outbreak of forest fires across Canada and North America. According to the Canadian Interagency Forest Fire Center (CIFFC), there were 911 active fires across the country on July 13, nearly ...
Earth Sciences
Jul 17, 2023
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18
Jet streams are relatively narrow bands of strong wind in the upper atmosphere, typically occurring around 30,000 feet, and blowing west to east. Their normal flows lead to week-to-week weather variations, modulated in the ...
Earth Sciences
Jul 17, 2023
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A solar storm forecast for Thursday is expected to give skygazers in some states along the U.S.-Canada border a faint glimpse of the northern lights which—at their peak—produce a colorful sky show when solar wind hits ...
Planetary Sciences
Jul 13, 2023
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21
A solar storm forecast for Thursday is expected to give skygazers in 17 American states a chance to glimpse the Northern Lights, the colorful sky show that happens when solar wind hits the atmosphere.
Space Exploration
Jul 9, 2023
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Los Angeles residents may have been starved for sunshine this spring and summer, but scientists say there's been at least one welcome consequence: some of the region's cleanest air in years.
Environment
Jul 3, 2023
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Extreme temperatures have combined with habitual smog in Houston for more than two weeks, and Erandi Trevino feels the hazardous combination in her body.
Environment
Jun 30, 2023
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2
Researchers have found that the cooling effect that volcanic eruptions have on Earth's surface temperature is likely underestimated by a factor of two, and potentially as much as a factor of four, in standard climate projections.
Earth Sciences
Jun 23, 2023
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186
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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