Noble gas in the United States alone. For large-scale use, helium is extracted by fractional distillation from natural gas, which can contain up to 7% helium. Neon, argon, krypton, and xenon are obtained from air using the methods of liquefaction of gases, to convert elements to a liquid state, and fractional distillation, to separate mixtures into component parts. Helium is typically produced by separating it from natural gas, and radon is isolated from the radioactive decay of radium compounds. The prices of the noble gases are influenced by their natural abundance, with argon being the cheapest and xenon the most expensive. As
Atmosphere of Pluto about distance to the orbiting moon. As early as the 1940s, Gerard Kuiper searched for evidence of the atmosphere in the spectrum of Pluto, without success. In the 1970s, some astronomers forwarded the hypothesis of a thick atmosphere and even oceans of neon: according to some views of those times, all other gases that are abundant in the Solar System would either freeze or escape. However, this hypothesis was based on a heavily overestimated mass of Pluto. No observational data about its atmosphere and chemical composition existed at the time. The first strong, though indirect evidence of the atmosphere appeared