The International Astronomical Union has posted a draft definition of “planet” that will serve to define our solar system and all others for all time!
Well, not exactly, as Phil Plait over at badastronomy.com points out quite well. The rules boil down thus:
1) It’s got to be big enough to be spherical due to it’s own gravity.
2) It’s got to orbit a star, not another planet or satellite.
Go to the Phil Plait link above for a full debrief on why this is rather arbitrary and stupid.
I have an opinion, though.
My opinion is that if they’re going to be arbitrary about the definition of a planet, why not be wholly arbitrary and not worry about the science. Here’s my take on the whole thing:
1) The Solar System has 9 Planets
2) Pluto keeps planet status just because it’s been a planet for 70 years.
That’s it. Nothing further. Entirely arbitrary. Make it so, number one…