[meteorite-list] Astronomers to Decide What Makes a Planet

[Ron Baalke]

> 
>     Two, 2003UB313 IS a planet under the "rules" that were in effect at
> the time of discovery. 

There is no formal definition for a planet, and that it the crux of the
problem. The IAU will be providing a formal definition soon.

>You don't change the rules after the game is over
> because you don't like the outcome, not even in Paris (or do you?). 

It is not a game, it is just a classification, which is being modified
to accomodate the latest data.  Just look at how meteorites are classified.
We would like to classify each meteorite cleanly into its own subgroup.
But we occasionaly run into a meteorite that doesn't fit very well
in the current classification scheme, so we temporarily label 
it as 'anomolous'.  We eventually modify the classification to 
accomodate these anomolous meteorites, usually by creating a new subgroup, or
expanding the definition of an existing subgroup.  Same thing with the planets.
We have a few anomolous objects that don't fit very in the current
classification, which was poorly defined to begin with.  We are going 
through a process of reclassifcation based on the latest data, which
was long overdue.

Ron Baalke