Jeff Morris wrote:



Here's a site that describes the Differential Gravity in a fairly simple way:
http://burro.astr.cwru.edu/Academics...ity/tides.html


That page shows a (trivial) spatial differentiation of a gravity field.
Not a good explanation IMHO -the terms used are not described at all...
What is the "center of mass force" and why is that different from gravity?

The force vector diagram makes no sense at all. How to you add the vectors:

- -- ---

to the center of mass force

-- X --

to get

-- X --

(note the reversal in direction at the left!) Must be some new maths!
(If it were so why don't people fly of into to space at the equator?).

Even worse, the site then goes on to use the _differential_ expression
to calculate the ratio of forces between the moon and sun!

Cheers