Pity poor Pluto, promptly punted 'pon his posteriorSome 50 years ago, US Supreme Court Justice Potter Stewart dodged the rather thorny issue of defining the term "hard-core pornography" by saying ""I shall not today attempt further to define the kinds of material Iunderstand to be embraced within that shorthand description; andperhaps I could never succeed in intelligibly doing so. But I know it when I see it." That's the problem with defining things. You think you have a perfectly good, intuitive definition for something, but if you actually have to define it, you notice all sorts of exceptions and problems. That's exactly the case with planets. The ancient Greeks came up with the name. It means "wanderer." A star that moves around. 'Cuz that's what they saw. So you can't really fault them for it. After Copernicus and Galileo, we were starting to get a pretty good handle on the whole planet thing. There weren't very many of them, and we could tell, finally, that they were different from stars. Galileo noticed that Jupiter had moons and Saturn had rings, which was all pretty cool. Just after the turn of the century, though, a guy called Giuseppe Piazzi discovered Ceres. (He actually wanted to call it Ceres Ferdinandea--Ferdinand being Ferdinand I of the Two Sicilies, but that was probably a bit too political for the scientific community). Okay, at first he thought it was a comet, but after observing it for a bit, it was decided that Ceres was actually a planet. A new planet in the solar system! And what's more, it was where the Titus-Bode Law predicted a planet should be. Very soon after Ceres was discovered, though, Pallas, Juno and Vesta were discovered in roughly the same orbit. They were disappointingly small for planets, though, not appearing as anything more than a point of light in even the most advanced 19th century telescopes. So they were called "asteroids." Star-like. After a while, more and more asteroids were discovered. So many, in fact, that around the turn of the 20th century, astronomers had taken to calling them "the vermin of the sky." So many, that people started naming them things like Mr. Spock and Misterrogers. Wait a second. What does this have to do with Pluto? To Be Continued! comments:This post is archived. Comments are disabled. Feel free to send me email if you have something to say. | |
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