To qualify as a planet:- 1. Its own gravity has had to make it round(ish) 2. It has to orbit the Sun 3. It has had to have cleared all the debris from around itself, whatever that means. So Pluto qualifies with Charon, Ceres and the other one whose name I've forgotten. Only a minority of the body who decides these things voted to downgrade it and lots of astronomers have protested. So it may be upgraded again. Janine PS I fulfill 2 & 3 but not 1 so I'm not a planet!
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