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Helium. hexagonal close-packed (hcp) Helium (from Greek: ἥλιος, romanized: helios, lit. 'sun') is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table.
Cosmological lithium problem. In astronomy, the lithium problem or lithium discrepancy refers to the discrepancy between the primordial abundance of lithium as inferred from observations of metal-poor (Population II) halo stars in our galaxy and the amount that should theoretically exist due to Big Bang nucleosynthesis + WMAP cosmic baryon ...
Rare gases is another term that was used, [7] but this is also inaccurate because argon forms a fairly considerable part (0.94% by volume, 1.3% by mass) of the Earth's atmosphere due to decay of radioactive potassium-40. [8] Helium was first detected in the Sun due to its characteristic spectral lines.
Helium-3 (3He[1][2] see also helion) is a light, stable isotope of helium with two protons and one neutron. (In contrast, the most common isotope, helium-4, has two protons and two neutrons.) Helium-3 and protium (ordinary hydrogen) are the only stable nuclides with more protons than neutrons. It was discovered in 1939.
HOW IS IT USED? Helium is used to pressurize fuel tanks, ensuring fuel flows to the rocket's engines without interruption; and for cooling systems. As fuel and oxidiser are burned in the rocket's ...
Until this year, the U.S. was counting on Russia to ease the tight supply. An enormous new facility in eastern Russia was supposed to supply nearly one-third of the world’s helium, but a fire ...
Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number; [5] siderophiles shown in yellow. Graphs of abundance against atomic number can reveal patterns relating abundance to stellar nucleosynthesis and geochemistry. The alternation of abundance between even and odd atomic number is ...
Why are major powers so interested in what is up there? ... HELIUM-3. Helium-3 is an isotope of helium that is rare on earth, but NASA says there are estimates of a million tonnes of it on the ...