Dwarf Planets

The International Astronomical Union (IAU) demoted Pluto from a planet to a dwarf planet in 2006 because many new objects have been found that are about the same size as Pluto. The likelihood of this number of objects increasing threw into question the definition of a planet. A dwarf planet orbits the Sun, is large enough to pull itself into a spherical shape due to gravity, and has not cleared the neighborhood around its orbit.