Pluto aficionados, rejoice! Pluto is a planet. So are the giant asteroid Ceres, Pluto's moon Charon, and a large outer-solar system object called 2003 UB313. The solar system has 12 planets instead of the familiar 9, according to a proposal that the General Assembly of the International Astronomical Union (IAU) will vote on next week in Prague, Czech Republic.
The IAU had asked a panel of seven astronomers, writers, and historians to better define what constitutes a planet. According to that panel's proposal, announced this week in Prague, a planet is any body that orbits a star, is neither a star nor a satell