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Helium-4 is an unusually stable nucleus because its nucleons are arranged into complete shells. It was also formed in enormous quantities during Big Bang nucleosynthesis. [113] Helium-3 is present on Earth only in trace amounts. Most of it has been present since Earth's formation, though some falls to Earth trapped in cosmic dust. [114]
Air composition, temperature and atmospheric pressure vary with altitude. ... Every second, the Earth loses about 3 kg of hydrogen, 50 g of helium, and much smaller ...
Helium: He 0.000524 Krypton: Kr 0.000114 Hydrogen: H 2: 0.00005 Xenon: Xe 0.0000087 Standard Dry Air is the agreed-upon gas composition for air from which all water ...
In Earth's atmosphere, the ratio of 3 He to 4 He is 1.343(13) × 10 −6. [5] However, the isotopic abundance of helium varies greatly depending on its origin. In the Local Interstellar Cloud, the proportion of 3 He to 4 He is 1.62(29) × 10 −4, [6] which is ~121 times higher than in Earth's atmosphere.
Composition of dry atmosphere, by volume [ note 1] [ note 2]; Gas (and others): Various [1]: CIPM-2007 [2]: ASHRAE [3]: Schlatter [4]: ICAO [5]: US StdAtm76 [6]: Tap ...
Helium also has a very low boiling point (-268.9°C or -452°F), allowing it to remain a gas even in super-cold environments, an important feature because many rocket fuels are stored in that ...
The composition of Earth's atmosphere is determined by the by-products of the life that it sustains. Dry air (mixture of gases) from Earth's atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen, helium, and other "noble" gases (by volume), but generally a variable amount of water vapor is ...
A global helium shortage has doctors worried about one of the natural gas’s most essential, and perhaps unexpected, uses: MRIs.. Strange as it sounds, the lighter-than-air element that gives ...