Planets again

[mmcirvin]

...And now the AP says the IAU has gone in the less expansive direction, distinguishing between dwarf planets and real planets and demoting Pluto. I can't tell exactly from the article but it sounds as if there's a qualifier that excludes objects obviously part of a population of similar bodies in similar orbits.

(The article claims that Pluto is disqualified because its orbit "overlaps" Neptune's, but that can't be right without further detail, or it would disqualify Neptune too! I would think that Pluto is disqualified because it's one of a whole population of similar bodies in similar orbits, some of which are of comparable or even greater size.)

Comments

[mmcirvin.livejournal.com]

I think the article's claim about the reason for Pluto's disqualification is wrong. I think what the IAU is trying to get at is that the existence of many comparable plutinos and other Kuiper Belt objects disqualifies Pluto (but then, as I said, you'd also have to make sure the definition doesn't disqualify any giant planet with Trojan asteroids).