On Thu, 4 Oct 2001, Dale K Stalnaker wrote:
> Afterwards, I had a conversation with someone who believed in a 6000-year
> old earth who gave the following points in favor of his position:
> 1. The Moon's orbit shows evidence of a young earth. I couldn't see the
> logic here.
> 2. Comets are evidence of a young earth, since they are short-lived and a
> source for these comets has never been proven to exist. He rejected the
> existence of the "Oort Cloud". Ironically, I asked him if it would bother
> him if the Oort Cloud was proven to exist and he said "no".
> Any comments about these arguments from anyone in this forum?
> Dale Stalnaker
Only short-period comets are short-lived. Since long-period comets can
become short-period comets by coming close enough to planets to have their
orbits altered by a planet's gravity, there is no reason to assume that
the short-period comets have always had short periods. The planes
containing the orbits of the planets are fairly close to each other and to
the planes of the orbits of most of the short-period comets. The orbits of
the long-period comets show no such preference. The long-period comets
that are most likely to be captured by the influence of a planet's gravity
are those that orbit in a plane close to that of a planet, and they are
also more likely to be captured if they revolve around the sun in the same
direction as the planets. This is exactly what we find is the case for
short-period planets. The great majority orbit in planes close to those of
the planets, and the great majority of those also orbit in the same
direction as the planets. Thus it seems reasonable to assume that the
short-period comets were previously long-period comets.
Department of Mathematics
University of Colorado
Boulder, CO 80309-0395
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