Jeff Morris wrote:

OK, Nav, its clear you're not going to get this without some help. You keep
claiming the centrifugal force varies across the Earth. However, that is not
the case. Your assumption is that the Earth is rotating around the E-M
barycenter, and that because that is offset from the Earth center, the
centrifugal force is unbalanced. (Or more precisely, you claim the "r" in the
centrifugal force equation is different on the near and far sides of the Earth.)


I think it's you that does not understand that the rotation force is
based on the lunar cycle -28 days!

However, if we remove the daily rotation,

Great idea -not based in reality of course.

the Earth does not move around the
barycenter quite like you think.

Like I think?

Only the center of the Earth describes a
circle around the barycenter.

So the Earth does wobble (now you are getting really close to the whole
story -where harmonics of all the orbital periods give a complete
answer). Now, don't all points on the surface move similarly around the
barycenter and if they do, what is the difference in their orbital path
to that of a circle? Now as I see it, from the math, the differential
gravity model takes no account of this, exploiting the idea that the
orbital motion of every point on the surface is perfectly circular
around the moon (thereby allowing a cancellation of the centrigal
component), a point that you seem to be having a bit of trouble grasping.

By the way, the differential gravity idea first came from Newton. It's
correct as far as it goes but the orbital mechanics of the Earth-Moon
pair are more complicated (as far as I've been able to read, Newton only
saw the free falling body aspect in his tidal proposal). The Devil _is_
in the details and you can't ignore the system rotation. This really is
my last post on this. If you still haven't got the idea then I really
can't make it any clearer and you'll just have to ponder why University
Departments of Oceanographics (and NOAA etc.) all say that THE TIDES ON
EARTH are due to the difference between centrifugal and gravity forces.

Cheers