Pity Poor Pluto part 3: Pity Poor AstronomersOkay, so picture you're an astronomer-type guy and you've just discovered a new thing out there way beyond Pluto. It's really just a rock--a hunk of dirt and ice. But it's yours and that's cool. Nearest you can tell it's pretty big, maybe as big as Pluto. Maybe bigger. You can keep it in context, though. In the grand scheme of things, it's part of a group of other objects and probably not all that unique. But it's news, because we haven't yet found all that many big, Pluto-sized things out there. Yet. So you get asked for a radio interview. I bet you can guess what the first question the interviewer's gonna ask is. "So, is it a planet?" And, if you're a scientist, that's a pretty annoying question. Mostly because, up 'till now, there wasn't any definition for what a planet was. So how do you answer that? I don't know for sure, but I'm betting that's why the IAU decided it had to come down with a decision. That's why Pluto isn't a planet anymore. Don't blame astronomers. Blame the media. (Everybody else does). I don't think the community of people studying this stuff really cares all that much, professionally anyway. They could probably content themselves with catalog numbers. I mean, they care, obviously. Because whichever way it comes down, they know they're going to have to answer for it at dinner parties. And that's annoying. So you might as well get it over with. I'm thinking the original proposal was sent out as a trial balloon explicitly for the purpose of being shot down, making the idea of demoting Pluto more palatable. But that's politics for you. When confronted with the same problem back in the 1850s, they just started calling them all asteroids and left it at that. Now they're calling them all "dwarf planets." Plus ça change, plus c'est la même chose. The new definition isn't fantastic. For one thing, it explcitly defines planets as being in our solar system, leaving out all the new extra-solar "planets" (for lack of a better word) that we're finding; the concept of "clearing the neighbourhood is a bit vague and not very intuitive; it doesn't address brown dwarfs (except that there don't appear to be any in our solar system anyway), and so on. This isn't the end, I'm sure. Reasoned, scientific discourse will likely refine the definition further. I don't think we could've had that discourse while Pluto was still defined as a planet, though. Because it was becoming increasingly obvious--even with our intuitive "I'll know it when I see it" definition--that it really wasn't. Or if it was, there are dozens, if not hundreds more like it out there. Which would just confuse the school kids, and get astronomers into even more trouble at dinner parties. To be continued? (I haven't decided. I would like to write something about astrology, though). comments:This post is archived. Comments are disabled. Feel free to send me email if you have something to say. | |
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