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Re: Moon's synchronism



Because the moon's orbit is not circular, it *can't* keep one face
precisely oriented toward Earth at all times. It's angular
velocity of rotation is roughly constant while its angular
velocity of revolution is decidedly not.

Students (as well as me) find (as I observed) interesting the result of
this discrepancy (the libration phenomenon): the observed face of the Moon
is slightly larger (5%?) than the hidden one. Isn't this an amazing fact?
(an evidence for Kepler's laws and an at hand phenomenon that might
encourage some to learn more about the on-face boring celestial mechanics?)



BTW, it's interesting to consider this phenomenon from a driven
oscillator point of view. The tidal force effectively drives the
moon at a frequency of about 1 cycle per month.

per month, or per 24 h?

But since that
frequency is *way* above the resonant frequency, the moon's
rotational inertia dominates.

"resonant frequency" of what?