Hruminations: Slashdot argues Pluto's planet-worthiness

Slashdot points to a Sydney Morning Herald article that attempts to quell the endless debate about whether Pluto is a planet. Here's the thread and my comment on this well-worn subject:


Planetary geology should be the first test (Score:1)
by jhritz (191620) on Wednesday March 12, @10:56AM (#5494212)

A widely held theory is that material surrounding the star sorts by mass with denser materials being closer to the star. These clouds of material condense into planets. You'd expect that metallic planets would be closest to the star, rocky ones next and icy ones (gas giants) last. At least in our solar system, we have bands of broken up rocky bodies (the asteroid belt between Mars and Jupiter) and icy bodies (the Kuiper belt between Neptune and the Oort cloud).

Large bodies that fall into the correct sorting areas would seem to be planets original to the star. Pluto, as a rocky body way out past the gas giants is probably not an original planet, but could be considered a captured planet for any number of reasons. It has its own, admittedly large, moon. It has a reasonably isolated orbit (which is way I'm reluctant to think of Ceres as a planet anymore than I think of the members of Saturns rings as moons). And yes, tradition. )