Nine Planets? More or Less

Friends, our solar system has eight planets, not nine as you've been told all your life. On second thought, maybe it has twelve. Actually, scientists can't agree, even after the International Astronomical Union (IAU)--the folks who officially keep track of celestial bodies--ruled in August 2006 that tiny Pluto isn't a planet after all. Here's the problem.

Up until August 2006, the IAU had no official answer to the question "what is a planet?" Instead, astronomers were left to sort it out for themselves. So, as astronomers started to find planet-like things out beyond Pluto, in what's called the Kuiper belt, confusion grew. One astronomer lamented, "It's something of an embarrassment. . . . We live on a planet; it would be nice to know what that was."

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