After dozly hearing the news on the radio yesterday morning, it struck me that the new definition of a planet would surely certainly pull in at least one of the asteroids, and lo it appears I was correct, as explained at Steve’s masterly summary of the planetary situation.

I was kinda hoping that Vesta would make it, too; I’ve always liked Vesta, but although it’s bright but presumably alas too small; although Mike Brown offers hope:

Wikipedia

A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet.

[…]

Despite what has been claimed in the media, this proposal does not automatically leave our solar system with 12 planets. Mike Brown, the discoverer of Sedna and 2003 UB313, has claimed that this definition could eventually comprise up to 53 planets in our system.

Now people are beginning to twig to the ramifications of what the IAU are up to; I’m just waiting to see what the astrologers get up to. If any of them claim to be sticking to the “traditional” nine planets, do take pains to remind them that Pluto was discovered in 1930.

So it’s hardly an ancient tradition.