Following Clyde Tombaugh's discovery of the distant object in February 1930, the Lowell Observatory staff sought a name fitting the mythological naming convention of the planets. Venetia Burney, reading about the discovery over breakfast with her grandfather in Oxford, suggested Pluto, god of the underworld, fitting for a cold, dark, distant world. The name was formally adopted and announced.
Clyde Tombaugh had spent months blinking between photographic plates at Lowell Observatory in Flagstaff, Arizona, searching for the hypothetical 'Planet X' that astronomer Percival Lowell believed was tugging on Neptune's orbit. On February 18, 1930, Tombaugh finally spotted a faint moving object. The observatory kept the discovery quiet for weeks while confirming it, then announced it to the world on March 13, Lowell's birthday.
The naming process that followed was surprisingly democratic. Suggestions poured in from around the world. In Oxford, England, an 11-year-old girl named Venetia Burney was told about the new planet by her grandfather, a retired librarian at Oxford's Bodleian Library, over breakfast. She suggested Pluto — the Roman god of the underworld, fitting for a world perpetually shrouded in darkness at the edge of the solar system. Her grandfather passed the suggestion along through a colleague to the Lowell Observatory.
Observatory staff voted unanimously for the name, partly charmed by the fact that its first two letters formed Percival Lowell's initials. On this day the name became official and was cabled to observatories worldwide. Pluto held its status as the ninth planet for 76 years until the International Astronomical Union reclassified it as a 'dwarf planet' in 2006 — a demotion Venetia Burney, who lived until 2009, took with good humor.