On Aug. 18, 1868, a French astronomer named Pierre Jules César Janssen discovered helium while observing a total solar eclipse in India.
During the eclipse, Janssen was using a spectroscope to look at the spectrum of light emitted by the sun. This tool allows scientists to determine what elements they're looking at. While observing solar prominences during the eclipse, Janssen noticed a bright yellow line that didn't correspond to any elements that was not yet discovered on Earth.
In the months that followed, English astronomer Norman Lockyer independently observed the same spectral line and concluded that it came from a previously unknown element, which was named helium after Helios, the Greek god of the sun.
Thirteen years later, the Italian physic...
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