Pity poor Pluto, part 2When William Herschel discovered Uranus (quiet, you! Actually, he wanted to name it after King George III, but that was probably a bit too political for the scientific community), it kicked off a flurry of speculation that there might be other planets as yet undiscovered. When they ran the numbers, they figured there were unaccounted for anomalies in Uranus' orbit. They figured out that the anomalies could be accounted for by a theoretical eighth planet in our solar system. They figured out where that planet was supposed to be and, lo and behold, there was Neptune. It didn't stop there, though. They found more anomalies in the orbits of both Uranus and Neptune. They thought maybe there might be some other "Planet X" that would account for it. "X" in this case means "unknown," by the way. Not 10. 'Cuz there were only 8 planets at the time. So they went looking for it. And lo and behold, there was Pluto. There were a couple problems, though. For one thing, Pluto was way too small to account for the orbital anomalies, so there's no way it could be Planet X. For another, there weren't any orbital anomalies. They just got the calculations wrong. So there never was any Planet X. At least not in the sense they were thinking. So despite having a weird orbit and being kinda small, Pluto became a planet. And people seemed happy it was a planet, even though scientist thought it was probably pretty boring. An icy ball of dirt a long way away. The Voyager probes passed on the chance to do a Pluto fly-by. Titan and Triton were decided to be that much more interesting. Science moved on and we kept discovering new things. It turns out there's lots of stuff out there near Pluto. Lots of little icy dirtballs. Pluto ended up being even smaller than was originally thought--it had a moon/twin planet, Charon, in close orbit. And it had an atmosphere. And the Pluto-Charon system had two more tiny moons. Of course, we know asteroids have moonlets too. And Pluto was starting to look pretty asteroid-like. Sure, it's bigger than Ceres, the biggest asteroid we knew about. But then they were starting to find other things that were almost as big. Pluto wasn't looking particularly special at all. And that got people to wondering, is Pluto a planet? And for that matter, what is a planet? And then, of course, they found 2003 UB313 (actually, they want to call it "Xena", but that may be a little too cheesy for the scietific community. Although calling its satellite "Gabrielle" was a nice touch). To Be Continued! comments:This post is archived. Comments are disabled. Feel free to send me email if you have something to say. | |
|