Friday, August 25, 2006

Pluto's demotion

Pluto vote revolting. :D Some scientists are kicking up a stink about the demotion of Pluto, some are happy.

Professor Iwan Williams, the IAU's president of planetary systems science, commented: "Pluto has lots and lots of friends; we're not so keen to have Pluto and all his friends in the club, because it gets crowded.
"By the end of the decade, we would have had 100 planets, and I think people would have said 'my goodness, what a mess they made back in 2006'."


I think, on the whole, I lean that way myself.

Dr Alan Stern, who leads the US space agency's New Horizons mission to Pluto and did not vote in Prague, told BBC News: "It's an awful definition; it's sloppy science and it would never pass peer review - for two reasons.

Pluto was discovered in 1930 by the American Clyde Tombaugh"Firstly, it is impossible and contrived to put a dividing line between dwarf planets and planets. It's as if we declared people not people for some arbitrary reason, like 'they tend to live in groups'.


"Secondly, the actual definition is even worse, because it's inconsistent."
One of the three criteria for planethood states that a planet must have "cleared the neighbourhood around its orbit". The largest objects in the Solar System will either aggregate material in their path or fling it out of the way with a gravitational swipe.
Pluto was disqualified because its highly elliptical orbit overlaps with that of Neptune.
But Dr Stern pointed out that Earth, Mars, Jupiter and Neptune have also not fully cleared their orbital zones. Earth orbits with 10,000 near-Earth asteroids. Jupiter, meanwhile, is accompanied by 100,000 Trojan asteroids on its orbital path.


The eight planet solution simplifies things, but in the context of school-l'arning, I don't think that's a bad thing. Interesting stuff.

What's in a name? :D

NASA's take on it

BBC Q&A

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