Helium: The Sun's Element That Was Found Before Earth
During the 1868 solar eclipse, Janssen’s spectroscope revealed a bright yellow line in the Sun’s spectrum that did not match any known Earth element, leading Lockyer to propose a new element named helium after Helios; it wasn’t isolated on Earth until Ramsay’s 1895 work, making helium the only element discovered in space before it was found on Earth and showcasing how spectroscopy lets astronomers read distant chemistry.