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.
Full Version: The 'planet' Debate
QUOTE (SFJCody @ Aug 27 2005, 08:04 AM)
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
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.
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