Plutonium Was Named After a Planet Named After a God of Death

The naming of element 94 followed a clear astronomical tradition. In the late 18th century, element 92 was named uranium after the planet Uranus. When element 93 was synthesized in 1940, it was naturally called neptunium after the next planet out, Neptune. So, when Glenn T. Seaborg and his team at the University of California, Berkeley, confirmed the discovery of element 94 in early 1941, they simply continued the sequence. They named it plutonium, after Pluto, which had been discovered just over a decade earlier and was considered the solar system's ninth planet.

This logical choice, however, carried an unintentional and chilling prophecy. The planet Pluto had been named by an 11-year-old English girl, Venetia Burney, in 1930; she suggested the name of the Roman god of the underworld because the new, distant planet was likely a dark and cold place. The scientists naming the element were initially unaware of its full potential, but under the secrecy of the wartime Manhattan Project, they soon discovered that a specific isotope, plutonium-239, could sustain a powerful nuclear chain reaction. This quality made it the fissile core of the "Fat Man" atomic bomb detonated over Nagasaki in 1945. The element named for a god of death had become an instrument of mass destruction, a grim fulfillment of its mythological namesake.