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Re: Moon's synchronism



How long after the earth's rotation becomes synchronous with the moon will
it become synchronous with the sun?

On Tue, 17 Mar 1998, Leigh Palmer wrote:

Our Moon spins in its axis at exactly the same rate (T=27.3 days) as
its period of revolution about the Earth. That is why we never see its
other side from Earth. Is this a pure coincidence? I suspect that there
must be some profound reason for this. What is it?

Relaxation of a system to its state of lowest free energy through
dissipation by tidal friction. The system is still relaxing; If
nothing else were to interfere, the Earth, too, would relax to a
state where its rotational period matches that of its revolution
around the Moon. Then the Moon would no longer rise anywhere on
Earth, just as the Earth does not rise when viewed from anywhere
on the Moon. When one considers what that's done to the relative
values of rea; estate on Earth and Moon, well, what a calamity!
Fortunately it won't happen. The Earth will be consumed in fire
before that time because the Sun will become a red giant in only
five billion years, give or take a couple of weeks.

Leigh