Helium was found on the Sun 27 years before anyone found it on Earth.
In 1868, astronomers studying a solar eclipse spotted a mysterious yellow line in sunlight that matched no known element. Norman Lockyer decided it was something new and named it after the Greek word for Sun. Chemists did not isolate helium on Earth until 1895.
Every element, when heated, glows at its own precise set of wavelengths, a spectral fingerprint. On 18 August 1868, during a total solar eclipse visible from Guntur in India, the French astronomer Jules Janssen saw a bright yellow line in light from the Sun's outer layer. It sat close to the known lines of sodium, and at first people assumed that is what it was. That October the English astronomer Norman Lockyer observed the same line and concluded it came from an element unknown on Earth. He called it helium, from helios. The '-ium' ending, normally reserved for metals, suggests an astronomer unfamiliar with chemists' conventions.
The earthly discovery came in 1895. The Scottish chemist William Ramsay was hunting for argon in a uranium mineral called cleveite when he saw the same yellow line glowing in the gas he released. Swedish chemists Per Teodor Cleve and Abraham Langlet isolated it independently that year. An American, William Hillebrand, had seen the lines earlier but put them down to nitrogen, a famous near miss.
Helium turns out to be everywhere, just not here. It is the second most abundant element in the observable universe, most of it made in the Big Bang, and stars forge more by fusing hydrogen. On Earth it is rare: about five parts per million of the air. Most of our helium comes from the slow radioactive decay of uranium and thorium underground, and it gathers in natural gas fields, where it was found in quantity in Kansas in 1903.
It is also a resource we cannot easily keep. Released helium is so light that it escapes the atmosphere into space. Liquid helium, the coldest-boiling of all elements, cools the superconducting magnets in MRI scanners, and its supply is thought to be shrinking.
Source: Wikipedia — Helium · Text summarised from Wikipedia (CC BY-SA 4.0)
