Here's why:
* Not a planet: In 2006, the International Astronomical Union (IAU) redefined the definition of a planet. To be considered a planet, an object must:
1. Orbit the Sun.
2. Be massive enough to be rounded by its own gravity.
3. Have cleared its neighborhood of other objects.
* Pluto fails the third criteria: Pluto shares its orbital space with many other objects in the Kuiper Belt.
Therefore, Pluto was reclassified as a dwarf planet, along with other similar celestial bodies like Eris and Ceres.
