[meteorite-list] 'Plutons' Push Planet Total Up To 12

From: Rob McCafferty <rob_mccafferty_at_meteoritecentral.com>
Date: Wed Aug 16 16:31:48 2006
Message-ID: <20060816203146.35201.qmail_at_web50907.mail.yahoo.com>

> >
> > I predict the IAU will get some really nasty
> letters from the
> > Luna City Chamber of Commerce, demanding the the
> Earth-Moon
> > System be recognized as a DOUBLE PLANET, since it
> meets
> > all the criteria applied to Pluto-Charon System.
> >

What are the criteria applied to the Pluto/Charon
system?
I too pondered how Pluto/Charon but not Earth/Moon may
be defined.
My resolution was that any bodies orbit their common
centre of mass. For Earth/Moon, this point resides
below the surface of the Earth (if memory serves
correctly) so to all intents and purposes, you can
claim the Earth is at the centre. For Pluto/Charon,
that is not the case.
That's why I ask the criterion used.

Personally, I always thought this was a nonsensical
argument. The original "planetos" were literally
"wanderers", stars that moved to naked eye observers.
By that definition, there are only 5 planets, the ones
known to the ancients.
I cannot understand the argument about ceres. It was a
planet for 70 years then it wasn't again because of
it's size! Huh! It's 1/10 the diameter of the earth,
but the earth is 1/10 the size of Jupiter. The make-up
of Ceres is a lot closer to earth's than Jupiters?

The whole concept of "planet" is daft and should be
limited to it's original concept. We've long divided
the planets according to "terrestrial" and "gaseous"
when the types have had little else in common other
than being visible to ancient astronomers. I'd like
the term "pluton" to be accepted as an acknowledgement
of diversity.

Rob McC

just being Devil's Advocate

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Received on Wed 16 Aug 2006 04:31:46 PM PDT