helios

Helium comes from Greek helios, meaning 'sun.' Helios was the sun god in Greek mythology, brother to Selene (the moon) and Eos (dawn). The root *sawel- goes back to Proto-Indo-European. The sun was the first god; its name is old.

In 1868, during a total solar eclipse, French astronomer Jules Janssen noticed a bright yellow line in the sun's spectrum—a line that didn't match any known element on Earth. English astronomer Norman Lockyer confirmed the observation and named the unknown element helium, after the sun. The element existed in the sun long before anyone proved it existed on Earth.

The irony was elegant: scientists had to look at the sun—a thermonuclear furnace burning 600 million tons of hydrogen every second—to discover a new element. Helium is the byproduct of hydrogen fusion. The sun produces its own helium. For decades after discovery, Earth had no helium anyone could identify.

In 1895, helium was finally isolated on Earth, found in uranium mineral deposits. But the name had already been fixed. We named the element after the sun because that's where we found its signature first. The element that powers stellar furnaces carries the sun god's name—the most ancient divinity remembered in modern chemistry.