A secondary category of planets, but not actually. Dwarf planets are bodies of rock that orbit the Sun and are too small to classify as a planet. The Dwarf planets in our solar system as of this definition are Ceres, Pluto, and Eris.
1. Pluto was a planet until the discovery of a bunch of objects about its size brought it down to dwarf planet. All those bodies will soon be dwarf planets.
by gnase October 5, 2006