The 'planet' Debate Options

[SFJCody]

It seems that the IAU is having a tough time defining the term 'planet'. Why is a debate that is irrelevant to the understanding of the solar system proving so contentious?

Summaries of the suggestions so far and what they would do to the number of 'planets':

Mike Brown, discoverer of 2003 UB313:
Anything orbiting the Sun that is larger than Pluto is a planet.
+2003 UB313

Brian Marsden, director of the IAU's Minor Planet Centre:
Any newly discovered body orbiting the Sun must be larger than Mars to be called a planet.
-Pluto (but not Mercury)

Alan Stern, PI for New Horizons:
Any body orbiting the sun that forms itself into a spheroid through self-gravity is a planet.
+2003 UB313 and a dozen or more main belt asteroids and TNOs

Iwan P Williams, president of the IAU's planet definition working group:
No new planets, regardless of size.

Thoughts on this from the forum?
Also, does anyone have a complete list of the members of the planet definition working group? The IAU website is unhelpful.

[helvick]

Alan Stern, PI for New Horizons:
Any body orbiting the sun that forms itself into a spheroid through self-gravity is a planet.
+2003 UB313 and a dozen or more main belt asteroids and TNOs

I like this one - if you think about what we would call objects we find orbiting around other suns then I think that would be a reasonable way to apply broad categorisation.

[SFJCody]

An article on the debate:

http://www.theglobeandmail.com/servlet/Art...TO27/TPScience/