Why is Pluto called a dwarf planet ?
Dear Student,
The International Astronomical Union decided in 2006 that Pluto should be described as dwarf planet which is more developed than asteroids, but different than the known planet.
Pluto, Eris and the asteroid Ceres became the first dwarf planets. Unlike planets, dwarf planets lack the gravitational muscle to sweep up or scatter objects near their orbits. They end up orbiting the sun in zones of similar objects such as the asteroid and Kuiper belts.