Re: Small Comets source of earth's ocean

Mark Grant (
Mon, 25 Aug 1997 21:22:54 +0000

On Mon, 25 Aug 1997 wrote:

> Anders wrote:
> Most solar system models seems to predict them in the outer
> solar system, and the few planets we have discovered outside the
> solar system are (almost by definition due to our measurement
> methods) gas giants.

Good point, but AFAIK we've still found few stars which have such planets;
some (many?) of the other stars could still have planets which are just
too small to see.

> It might even be completey fact if the idea's behind the
> "Kirkwood" zones are correct then the presence of a gas giant such as jupiter
> puts earth more at risk..not less.

Hmm, I'm not sure of the theory you're quoting, but if it's what I think
it is (that Jupiter pulls comets into the inner solar system when they
wouldn't otherwise come here) then I guess it would depend on whether the
gas giant is better at 'hoovering up' passing comets or pulling new ones
in. I can't see an obvious reason for preferring one possibility over the


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