Aug. 18, 1868: Helium is discovered

Today in the history of astronomy, an eclipse spotlights a new element.
By | Published: August 18, 2025

During the total solar eclipse of Aug. 18, 1868, two astronomers, Pierre Jules César Janssen of France and J. Norman Lockyer of England, each independently discovered a new line in the Sun’s spectrum. Lockyer thought it showed an undiscovered element, which he named helium. (In Greek mythology, Helios was the Sun god.) Although scientists would later show that helium is the second most abundant in the cosmos, it wasn’t found on Earth for another 27 years.