Well, there are a few things I don't like about it, but over all it's an OK definition.

Double Planets. Obital Dominace would not classify them as planets at all, even if they were the only two bodies in a particular orbit. The issue posted with the Bary Center didn't use the inverse square law of gravity but a simple proportion. It would actually take a body almost two times the moons mass at it's distance to have a bary center at earths surface, to get it out of the atmosphere, its almost 3.8 times the moons mass.

I think the Bary center for defining double planets is still a valid aproach, when you account gravity work on an inverse square.

The other issue.

I'm not fond of anything the declassifies the Pluto/Charon system as a planet(double). For this reason the Size classaifaction makes more sense then redefining.

Although it's not likely it's entirely -posiible- to have a asteroid like belt of mars to earth sized objects in the habitable zone of a star, if they had a Gas Giant close enough on each size of the plantary cloud to keep the cloud stablized. In this case there could be easily a dozen or more habitable earths all sharing the same orbit.

And they would still be planets.

I think orbitable domince, and size should both make a case for planet hood, not one over the over.

In the case of Pluto/Charon, a classification as Double Planet fits, I see no valid reson to demote them, scietifically or other wise from that status.

Not pointing fingers at any -one- person, but lately I've come to the conclusion that for some reason classifing 2003 UB313 as a planets seems to actually offend a few people. I'm not exactly sure why that is.

I think any classification that excludes both Pluto/Charon and UB313 from a planatary classification is a mistake. 90% of the folk out there would be irritated to say the least if suddenly they had to back petal on calling Pluto a planet. How would science be precieved if suddenly they came out and said 'well, it's not really a planet' especially when that perception could be carried over into other issues where it's far more import for science to make a stand on.

Over all were stuck with pluto as a Planet, and hence, UB313 as one too.

But this is all moot until the IAU nails it down officially, one way or the other.

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