Re: Tidal Force Tensor

"Alfred Einstead" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> [EMAIL PROTECTED] (WaiteDavid137) wrote:
> > It would be a bad term if they did.
>
> It's entirely appropriate and the understanding behind it is fairly
> standard, centering on the equation of geodesic deviation:

waite has the impression that "tidal force" is not defined as you and I have
described it. He believes that tidal forces are defined accordining to
differences in coordinate acceleration, the existance of such differences
are, in general, coordinate dependant. This definition, of course, is
untrue. The rising and falling of ocean tides can't arise from changes in
coordinate systems and that is where "tidal force" gets its name. If there
is no relative acceleration of free-test particles in a free-fall frame then
there are no tidal accelerations in any frame. Hence the reason the Riemann
tensor is also called the relativistic tidal force tensor.

Pmb