correction re age of sun and moon

Bill Hamilton (whamilto@mich.com)
Sun, 29 Sep 1996 15:06:56 -0400

In a private email David Bowman pointed out an error I made in one of my
posts on this subject. I implied that the tidal bulge has a higher angular
rate than the moon. This is not so. Friction between water and earth
causes the tidal bulge to lead the angular position of the moon by a phase
angle which stays approximately constant. This moves the line of action of
the gravitational attraction slightly away from the centerline between
earth and moon, and this off center force contributes angular momentum to
the moon, causing the observed recession. And of course the friction
between the earth and the water causes the earth's rotation rate to decay.
Thanks, David.

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William E. Hamilton, Jr., Ph.D.
1346 W. Fairview Lane
Rochester, MI 48306
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