Re: Planet Definition revised

I think this entire IAU meeting is sheer nonsense and a complete waste of
time. Why don't they just *define* the current 9 planets as such and stop
haggling about whether our solor system has 8,9,11 or hundreds of planets.

No one definition will satisfy everyone but it's perfectly reasonable to
stick to the current definition of things for historical reasons.


"steve" <stephen.colbourne@xxxxxxxxxxxxxxx> wrote in message
news:1156318353.296230.103970@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
See:-

http://www.space.com/scienceastronomy/060819_new_proposal.html


It is proposed that part of the planet definition should be a
requirement that :-

(a) is by far the largest object in its local population[1],
[1] The local population is the collection of objects that cross or
close approach the orbit of the body in consideration.


I can see that Pluto would by this lose its right to being a planet due

to Neptune.


But what of two similar sized objects the size of Earth in the same
orbit, maybe even orbiting each other as a binary system (whilst still
orbiting their star). surely these deserve to be planets


I still think the previous rules about the position of the COG make
more sense, and making the cut off size some arbitary size big enough
to keep the proposed number of planets to a reasonable number is
sensible.


I would simply say make this size bigger (or equal) than Pluto if we
still want Pluto.
Or
Bigger than (or equal to ) Mercury .


The idea of using a size big enough to make sphere by gravitational
forces might be elegant but is rather small , resulting in many more
planets than we can sensibly handle.




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