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From: goutal@dec-parrot.UUCP
Newsgroups: net.astro.expert
Subject: black holes and comets
Message-ID: <1457@decwrl.DEC.COM>
Date: Sun, 2-Mar-86 13:53:21 EST
Article-I.D.: decwrl.1457
Posted: Sun Mar  2 13:53:21 1986
Date-Received: Tue, 4-Mar-86 01:31:24 EST
Sender: daemon@decwrl.DEC.COM
Organization: Digital Equipment Corporation
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I'm not an expert, I'm asking for an expert answer on behalf of my
six-year-old daughter (who's no expert either).  We have access to
independent facts in the form of her encyclopedia (at the least),
but need someone to pull them together somewhat...

The question she asks is, why don't the comets get gobbled up by
black holes out beyond the planets?  Or, how probable is it that
any given comet might get thus, er, eaten?  (Probably not accurate
to say "destroyed".)  Or, how many comets might might thus be
eaten over a period of time?

The answer I gave her was that, as far as anyone knows, black holes
are not all that common, at least not ones that are big enough to
do that kind of damage.  We wondered if a black hole that was big
enough (however you want to measure "big") to absorb comets might
be big enough to be detectable in the orbits of the known planets,
thus qualifying as "Planet X" or whatever, that was what Pluto was
supposed to be but apparently isn't after all.

Can anyone shed any light on this for us?


-- Kenn	Goutal		...decwrl!dec-rhea!dec-parrot!goutal