Pluto to Officially Become a Planet-- and Now we have 12!

Astronomers meeting in Prague today have announced that they have drafted a set of rules that declares Pluto will officially be recognized as a planet (Goofy was unavailable for comment, badda bing!).

Not only that, but these rules add three more planets to the roster: Ceres (up until now considered a lowly asteroid), Charon (Pluto's moon), and the prosaically-named UB313 (an iceball slightly bigger than Pluto and chillingly even farther from the Sun).

So if these rules are ratified, which is by no means certain, schoolchildren will have to learn the names of 12 planets. Of course, UB313 hasn't been named yet. I sure hope they don't let its nickname stick: Xena. And yes, it has a moon, and yes, it's nicknamed Gabrielle.


Reactions among astronomers appears to be mixed. I'm an astronomer, and I think the rules are basically OK, but arbitrary. I have a sneaking suspicion the people in the committee who made the rules engineered them to include Pluto. I can't prove it, though. But including its moon in the list of planets is just weird (and a by-product of the more mathematical nature of the rules). Our own Moon is much larger!

But the real bottom line is, these rules are silly. We don't need a definition of what a planet is: it's a cultural thing, not a scientific one. We're arguing semantics here, not facts and data. Whether we call Pluto a planet or not (or UB 313 Xena), it'll still be the same dinky ball of ice that takes 248 years to orbit the Sun.

You can read more about this on my blog, and read the rules for yourself at the International Astronomical Union web site.