Re: moon's synchronism

[Jim Green <JMGreen@sisna.com>]

> Just a point of clarification (I hope!):  Friction (or more, generally,
> dissipation) is not particularly necessary to *maintain* the moon's
> synchronization although it does help guard against its loss due to
> external perturbations.  On the other hand, it was certainly needed to
> *produce* the synchronization in the first place.
>
> John

John, I was thinking that you held this thought in the back of your mind
during this discussion:  I need help understanding this.

Let me give my view for your consideration and comments:  

However the Earth/Moon system came to be, I assume that there was a time
when the Moon was molten and then plastic as it cooled.  During this time
the Earth's gravitational field caused bulges (OK, tidal bulges) on the Moon
which, as long as the Moon was plastic and reasonably homogeneous followed
the Earth. (In the same way that we now, erroneously, <sorry David> think
the Earth's oceans have "tidal bulges" which follow the Moon.)  BUT the
Moon's bulges are NOT dependant on any water on the Earth -- this could well
have happened in the case of a dry Earth.  (The outer planet's moon's don't
serve as examples here as these planets are still liquid or plastic) 

What resulted was a yam shaped Moon with its long axis pointed generally
toward the Earth.  The Moon is oscillating slightly in this orientation -- I
am not sure why -- whether it is just not yet damped out or if it is
continually perturbed - ther are opinions each way.

Now each time the Moon "swings", there is an applied torque to bring it back
because the force on the near side is greater than the force on the far
side.  This applied torque would be essentially the same for a wet Earth or
for a dry Earth.  Yes there is an additional effect due to the Earth's
oceans which causes the Moon gradually to slow and recede, but this has
essentially nothing to do with synchronization.

I am now ready for the flames.

Jim Green
JMGreen@sisna.com