Planet X

Pluto, originally referred to as Planet X, got its name from an 11-year-old student in Oxford, England. Venetia Burney suggested that the god of the underworld made the best namesake for what was thought to be a cold, lifeless planet. Astronomers liked the name because it started with “PL,” the initials of Percival Lowell, the man who first predicted the probable location for Planet X. Lowell died in 1916, 14 years before the planet was discovered.