--- Chuck Hards <chuckhards@yahoo.com> wrote:
And what nags at me is, WHY do scientists even WANT to make the "home-grown" distinction at all? It seems totally unnecessary and pathologically compulsive.
I place the whole "it's not a planet" controversey in the same place I store Saint Thomas Aquinas' philosphical transactions on whether several angels could be in the same place at once - the source of the "how many angels can fit on the head of a pin" popular witticism. I'm perfectly happy with the informal cultural definition of a planet as something (1) alot bigger than me, (2) somewhat rounded by gravitational attraction and (3) orbits a sun. I loose no sleep wondering if Sedna, Xena or Pluto are planets. Personally, I feel that none of them are planets; they are all big tail end of the normal distribution of Kupier Belt objects. My intent was to show that IAU could reduce the amount of energy that people put into this nonsensical question by adopting _any_ formal scientific criteria for the definition of a planet.
<snip> What is the justification for the 50% accretion cut-off?
It is arbitrary but seems to work as a rule-of-thumb from what little I know of moons in the Solar System. I can't think of any moons in an orbital track that haven't sucked up at least 1/2 the matter in its orbit. There's either a Moon in an orbital track or an orbital track that is a highway of rubble. Know of any exceptions?
Assuming the in-situ accretion percentage makes or breaks a planet, what do you call those objects that look like planets, walk like planets, & quack like planets, but didn't form in the system you find them in or don't orbit a fusor at all? <snip>
Well, when professional astronomers _find_ any physical evidence of such an object - call me and I'll revise my cosmology. -:)
Could there be a real, scientific reason for it?
Good clear criteria in definitions that are easy to apply advance knowledge in other more potentially fruitful areas of inquiry by reducing the energy that people spend on non-sensical controver ---- just loop back to the top of this post. -:) Best wishes - Canopus56(Kurt) __________________________________ Yahoo! Mail for Mobile Take Yahoo! Mail with you! Check email on your mobile phone. http://mobile.yahoo.com/learn/mail