Basically, it boils down to this: Is Pluto a planet, or isn't it?
On one side you have your canon purists, who say that a vampire cannot be good without a soul Pluto should never have been classified as a planet in the first place. After all, it's just a big hunk of ice with a highly inclined and eccentric orbit. The redemptionistas say Pluto is too a planet, and should be recognized as such. They write Pluto/Charon fanfic and everything OTP!
So, the International Astronomical Union steps in with a solution, which states: If it's round and it orbits a star, it's a fucking planet, ok? Shut the fuck up.
Cue more wank, because this means we have twelve planets for starters, and more to come. We've got Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto/Charon and Xena (aka UB40...no, wait, they did Red Red Wine. Umm, some letter and number thingy.) The guy who discovered Xena, Mike Brown, is all "woohoo I discovered a planet!" but at the same time is stating that the entire thing is stupid and neither Pluto nor Xena are planets and pffft, I could cram Ceres up my ass without even blinking.
Oooh, the heated debate. How shall we ever make children memorize the order of the planets now? Do we need a new mnemonic? Here's one. Many Very Egotistical Motherfucking Cuntrag Jackoff Scientists Unleash Nefarious Pedantic Conversation about Red Red Wine.