Solar system's planets. Computer artwork of the planets of the solar system, as redefined in August 2006. The eight planets and the Sun (left) are shown here, along with three newly-defined dwarf planets (red boxes). From left to right, the planets and dwarf planets are: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto and Eris (formerly 2003 UB313). The International Astronomical Union (IAU) voted on 24 August 2006 to change the definition of a planet. This demoted Pluto from a planet to a dwarf planet. Eris is one of several objects in the outer solar system that, like Pluto, can now be considered a dwarf planet. Ceres is the largest of the asteroids in the asteroid belt.