Is Pluto a planet?

The short answer: yes and no. (You can tell when science and politics mix.)

The long answer. Heck, I don’t want to bother explaining it. If I did, would I really be writing it in a blog? Wikipedia sums it up nicely, as does this Washington Post article. Pluto is in trouble, but not of losing its planetary status—not quite.

You see, the problem with Pluto is that it’s puny. It’s the runt of the litter; it’s the planet that other, bigger, manlier planets bully in the solar schoolyard during celestial recess. And this size has recently become an issue as more and more planet-like objects are being discovered orbiting that star out there we call the Sun, which hundreds of years ago some guy named Copernicus tried to convince everyone all the planets orbit.

You know, if we had stuck with geocentrism, this probably wouldn’t be much of a problem, now would it? Alas, heliocentrism is a cold and unforgiving solar model.

So basically, the International Astronomical Union has to finally decide if Pluto is a planet or not? Unfortunately, no. It isn’t that simple. Because we’ve never really had a good idea of the definition of a planet anyway. As we built bigger and better telescopes and started discovering things farther away, we sort of just picked and chose what would be a planet or not. Back in those days, the solar system didn’t seem so crowded.

What the IAU is doing (finally) is promising us an “official” definition of a planet. (but then divide the planets up into categories). More on that later in September.

Nevertheless, it leaves us with the issue still on the table. How will society react to this redraw of the universe? Under the new proposed definition, Pluto is still technically a planet (I say “technically” because if it weren‘t, Disney would sue the IAC ), but we will add some new ones to the list (I’m not sure if they’re going to be “minor” planets or full-fledged members of the club, although I doubt the latter). All I know is, I’ll be out of school (or at least science class) before anyone publishes a textbook that has to cover the issue.

And if someone asks me how many planets there are, I’ll simply say, “Hundreds, man, a whole bunch orbiting hundreds of different stars in the galaxy.” And if some smart-alec goes on to goad me into telling them how many planets in the solar system we’ve got, well … have you seen how long my blog entry is?