Look, up in the sky… It’s nine planets… no, twelve… no, eight!
Ack! I spoke too soon. The IAU’s twelve-planet idea was a proposal, not a final decision. Today the astronomers of the world actually voted on the proposal, and decided to add one more criterion to the definition of planet: you can’t be a planet unless you’ve swept your orbital path clean. That rules out Ceres… and Xena… and Pluto and Charon. So much for an expanded planetary family!
August 27th, 2006 at 5:33 pm
I’m so confused. So how many planets am I supposed to tell my kids we have?