Helium

Helium (from ) 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. Its boiling point is the lowest among all the elements, and it does not have a melting point at standard pressures. It is the second-lightest and second-most abundant element in the observable universe, after hydrogen. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and

particle of alpha radiation; helium-4 nucleus; particle of two protons and two neutrons

emission of alpha particles by a decaying radioactive atom

French astronomer (1824-1907)

English scientist and astronomer (1836–1920)

nuclear fusion reaction chain converting helium to carbon

small balloon used as a children's toy

liquid state of the element helium

brief thermal runaway nuclear fusion in the core of low mass stars

A planet with a helium-dominated atmosphere

type of gas laser

mixture

Heliox is a breathing gas mixture of helium (He) and oxygen (O2). It is used as a medical treatment for patients with difficulty breathing because this mixture generates less resistance than atmospheric air when passing through the airways of the lungs, and thus requires less effort by a patient to breathe in and out of the lungs. It is also used as a breathing gas for deep ambient pressure diving as it is not narcotic at high pressure, and for its low work of breathing.

low-mass supergiant that is almost devoid of hydrogen

WASP-107b is a super-Neptune exoplanet that orbits the K-type star WASP-107. It lies 200 light-years away from Earth in the constellation of Virgo. Its discovery was announced in 2017 by a team led by D. R. Anderson via the WASP-South.

class O or B star

solar eclipse

nucleus of helium, a doubly positively charged helium ion. In practice, helion refers specifically to the nucleus of the helium-3 isotope, consisting of two protons and one neutron.

mathematical modeling of a helium atom

RasGas Company Limited was a liquefied natural gas (LNG) producing company in Qatar. It was the second-biggest LNG producer in Qatar after QatarEnergy LNG. RasGas operated seven LNG trains located in Ras Laffan Industrial City. It was merged with Qatargas on 1 January 2018.

hydrocarbon resource field in Russia

Hydreliox is an exotic breathing gas mixture of hydrogen, helium, and oxygen. For the Hydra VIII (Hydra 8) mission at 50 atmospheres of ambient pressure, the mixture used was 49% hydrogen, 50.2% helium, and 0.8% oxygen.

imaging technology based on a scanning helium ion beam

exotic matter with an antiproton in place of an electron