On 26/08/2009, at 11:24 PM, Alberto Monteiro wrote:
Charlie Bell write:
Either planets sweep their orbits of debris in which case we have
14+ or they don't and we have 8.
Uh? Isn't it the other way around?
Um, yes. :-)
But it's not a debate about Pluto. It's a debate about whether we
have lots of planets or we have some planets and some planetoids.
I think a much more interesting debate would be to try to explain
why Mars has two tiny moonlets and Venus and Mercury have none.
Probably (my guess) Mars's moons are recent acquisitions, and won't
last forever. Venus and Mercury may have had moonlets in the past
too, that lasted a few million years and then either crashed or
flew away.
IIRC, Phobos is falling and Deimos is leaving Mars.
...and our moon is leaving too.
It's all a matter of time.
C.
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