From: Michael S. Lorrey (mike@lorrey.com)
Date: Fri Aug 20 1999 - 21:43:10 MDT
Freeman Craig Presson wrote:
>
> On 19 Aug 99, at 6:01, James Daugherty wrote:
>
> > This post caught my eye on the net some time ago. Can anyone refute
> > any
> > of these co-incidences or point to possible theories explaining them as
> > necessary consequences of various physical laws?
> >
> >
> > Weird Coincidences
> > ------------------
> >
> > During a full eclipse, the disc of the moon is EXACTLY the same
> > size as the disc of the Sun.
>
> They're the same size other times, too :)
No they are not. The relative size of the moon to the sun actually
varies, because the moon's distance from earth at the time of the
particular eclipse is different every time, and the earth's distance
from the sun varies. astronomers actually have classified two types of
solar eclipses, one is an annular, and I don't recall off hand the name
of the other, but they differentiate eclipses where the moon is bigger
or smaller than the sun at the time of the eclipse.
>
> > This means that it PERFECTLY
> > covers the Sun, no more no less.
> >
> > What are the odds I ask you, what are the odds.
> >
>
> This is the only one that's really a long-odds coincidence. So far the
> empirical odds are 1/N, where N=total number of moons in the solar system ...
> (it might be interesting to figure out if any of the others come close). One
> could quibble with EXACTLY here, too, since the moon's orbital eccentricity
> produces both full and annular eclipses.
>
> >
> > Our Moon's period of rotation is EXACTLY equal to its period of
> > revolution around the earth.
>
> Already explained, tidal lock. Oh, and it's not exact, either, the moon
> wobbles.
Yes, as the moon comes into its waning stage, the tidal influence of the
sun causes it to speed up in its orbit of the earth (and it slows down
when its waxing), but its angular momentum keeps it rotating at the same
rate, causing us to be able to see a minor slice of the back side of the
moon at such times.
Mike Lorrey
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