Helium is the seicont lichtest element an is the seicont maist abundant element in the observable universe, bein present at aboot 24% o the tot elemental mass, which is mair nor 12 times the mass o aw the hivier elements combined. Its abundance is seemilar tae this figure in the Sun an in Jupiter. This is due tae the very heich nuclear bindin energy (per nucleon) o helium-4 wi respect tae the next three elements efter helium. This helium-4 bindin energy an aa accoonts for why it is a product o baith nuclear fusion an radioactive decay. Maist helium in the universe is helium-4, an is believed tae hae been fairmed durin the Big Bang. Lairge amoonts o new helium are bein creatit bi nuclear fusion o hydrogen in starns.
Helium is uised in cryogenics (its mucklest single uise, absorbin aboot a quarter o production), parteecularly in the cuilin o superconductin magnets, wi the main commercial application bein in MRI scanners. Helium's ither industrial uises—as a pressurizin an purge gas, as a protective atmosphere for arc waldin an in processes sic as growin crystals tae mak silicon wafers—accoont for hauf o the gas produced. A well-kent but minor uise is as a liftin gas in balloons an airships. As wi ony gas wi differin density frae air, inhalin a smaa volume o helium temporarily chynges the timbre an quality o the human vyce. In scienteefic research, the behaviour o the twa fluid phases o helium-4 (helium I an helium II), is important tae researchers studyin quantum mechanics (in parteecular the property o superfluidity) an tae those leukin at the phenomena, sic as superconductivity, that temperaturs near absolute zero produce in matter.
On Yird it is relatively rare—0.00052% bi volume in the atmosphere. Maist terrestrial helium present the day is creatit bi the naitural radioactive decay o hivy radioactive elements (thorium an uranium, awtho thare are ither examples), as the alpha particles emitted bi sic decays conseest o helium-4 nuclei. This radiogenic helium is trapped wi naitural gas in concentrations up tae 7% bi volume, frae which it is extractit commercially bi a law-temperatur separation process cried fractional distillation.
↑Helium: Up, Up and Away? Melinda Rose, Photonics Spectra, Oct. 2008. Accessed Feb 27, 2010. For a more authoritative but older 1996 pie chart showing U.S. helium use by sector, showing much the same result, see the chart reproduced in "Applications" section of this article.