Thursday, June 22, 2006

Pluto News

The International Astronomical Union has chosen Nix and Hydra as the names for the new moons of Pluto. The two moons were discovered by the Hubble Space Telescope last year. But the bigger news is found later in the article:
This summer, the IAU will debate whether Pluto should remain a planet. The discovery of an icy object slightly larger than Pluto in the Kuiper Belt last year reinvigorated the argument over whether to demote Pluto or add other planets. (emphasis and link added)
This is huge. Imagine all the books, textbooks, and trivia games that would have to be updated if Pluto were to lose its status. The vast majority of people on Earth today (excepting those born before 1930) have always "known" that there are nine planets in the solar system, and now that could change. On the bright side, at least demoting Pluto would eliminate the confusion about the planets' order from the Sun (Pluto's eccentric orbit makes it closer to the Sun than Neptune sometimes).

The IAU won't be asking me, but I would vote against Pluto as a planet. It doesn't fit in with the gaseous outer planets, the inclination and eccentricity of its orbit are peculiar, and it is small (half the diameter of Mercury). The Kuiper Belt contains a lot of similar objects, so what makes this oddball Pluto important enough to be a planet? I suppose one could argue that having moons elevates its status -- I don't know if any other objects in the Kuiper Belt have satellites. It will be interesting to see what the IAU decides.

On a personal note, we drove through Burdett, KS on our recent vacation. While turning the car around at the edge of town, I happened upon a historical marker noting that Clyde Tombaugh, the discoverer of Pluto, grew up and went to high school there. Of course, as a proud Illinoisan, I prefer to remember Tombaugh's birthplace, Streator, IL.

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