A hand holds a Pluto's Pumpkin Pursuit 2024 board from EPCOT, featuring a map with Disney locations like Test Track, The Seas Pavilion, and Mission: SPACE, among others, for a scavenger hunt.

Pluto was the little planet that could — until it couldn’t. Discovered in 1930 at Lowell Observatory in Flagstaff, Arizona, Pluto was hailed as the ninth planet in our solar system.

Pluto was declassified as a planet on Aug. 24, 2006, when the International Astronomical Union redefined the criteria for what constitutes a planet. It was reclassified as a dwarf planet because ...