Pluto Demoted - Solar System Has 8 Planets

The International Astronomical Union (IAU) has decided on a definition of planet that doesn’t include Pluto; what was the ninth planet in our solar system is now defined as a dwarf planet, as are the large asteroid Ceres and recently discovered 2003 UB313. The new definition, adopted today at the IAU’s 26th General Assembly, states that an object is a planet if it 1) is in orbit around the Sun, 2) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and 3) has cleared the neighborhood around its orbit. Pluto has not "cleared its neighborhood" as it shares its distant orbit with many other smaller objects. Check out the IAU press release for more info on this revolutionary decision. So, officially (according to the IAU) the solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, and three dwarf planets: Ceres, Pluto and 2003 UB313.