Post by hilbert on May 24, 2009 1:38:22 GMT
Im curious though - you mention tidal friction - does the additional 400 feet of oceans water (since 20,000 years ago) come into play in that or is ice age melt ignored?
I'm guessing not. The moon causes a tidal bulge (even in the continents, I think), but there is a delay between the tidal stretching force and the rising of the ocean, so the bulge doesn't point directly towards (and away from) the moon. This, in turn, causes a net decelerating torque on the earth. The loss of angular momentum of the earth goes into the moon drifting slightly farther away. I don't think that an extra 400 feet is going to matter much (I could be wrong, though).
In early times, the moon was quite a bit closer, and the earth was rotating quite a bit faster.