The solar system has only eight planets, and Pluto isn't one of them. That's the official word from the International Astronomical Union (IAU). On Aug. 24, astronomers at an IAU meeting in Prague, Czech Republic, voted overwhelmingly to demote Pluto from planet to "dwarf planet." In doing so, the astronomers also approved the first-ever definition of a planet.
Viewed as an oddball ever since its discovery in 1930, tiny Pluto loops around the sun in a highly tilted orbit relative to the orbits of earlier-named planets. As astronomers have discovered some 1,000 objects in Pluto's neighborhood, known as the Kuiper