Helium: Its Past, Present, and Future
A brilliant yellow spectral line at 5875 A was discovered in 1868 when the radiation emitted by the solar chromosphere was first analyzed spectroscopically. For the next few years, considerable effort was expended in an attempt to identify the source of this spectral line. Since it did not correspond with any ordinarily emitted by a terrestrial element, questions were first raised as to whether this new line might have originated from some well-known substance under extreme conditions of state. Eventually, however, it was acknowledged that the line must be characteristic of some new substance unique to the solar atmosphere and by 1871, physicists and astronomers were beginning to identify the line as belonging to a new element named helium, after the Greek work ἥλιος meaning “sun.”
KeywordsMethane Furnace Dioxide Sulfide Europe
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