Most of the motion in the universe is gyral; that is starting with
little eccentric motions, most of it "comes around full circle".
A gyral motion of 360 degrees, and a radius of one, will give a gyral
velocity or speed of 360 degrees per gyre, and a gyral acceleration
of: v^2/r = 360^2/r = a.
To keep this configuration intact about a central point requires an
average centripetal force that is equal to the centrifugal force that
the configuration tends to exert outward; which would ultimately
disperse the configuration:
Which is what would happen if the moon and Earth didn't have anything
to contain their configurations:
As it is, their configurations are maintained by the average inward
centripetal impulses exerted by the ambient pressure due to
electromagnetic impulses exerted by that medium.