Are there forces in relativity?

On Aug 6, 3:01*am, Tom Roberts wrote:
Darwin123 wrote in sci.physics.relativity:
* * *In "Gravitation" by Wheeler, Thorpe, et. al. a statement is made
that in relativity, "There are no forces and no. gravitational
potential." Several other scientists made broad statements like that,
although they don't describe what they mean in mathematical terms.

You surely misquoted. They almost certainly said "There are no
gravitational forces...". There most definitely are other types of
forces in relativity (e.g. that's what the standard model is all about,
though that is a different context than GR).

The most important force in relativity, Honest Roberts, is and will
remain forever the one the misfortunate 80m long pole trapped inside
the 40m long barn (after brothers Einsteinians forget to reopen the
doors of the barn "pretty quickly") exerts on the doors of the barn,
in its desperate attempt to restore its proper length:

http://www.math.ucr.edu/home/baez/ph...barn_pole.html
"These are the props. You own a barn, 40m long, with automatic doors
at either end, that can be opened and closed simultaneously by a
switch. You also have a pole, 80m long, which of course won't fit in
the barn....So, as the pole passes through the barn, there is an
instant when it is completely within the barn. At that instant, you
close both doors simultaneously, with your switch. Of course, you open
them again pretty quickly, but at least momentarily you had the
contracted pole shut up in your barn."

Sooner or later, Honest Roberts, the Great Theoreticians in Einstein
Criminal Cult will have to describe this force in more detail: How
great is it? Can it break any doors of any barn? Can it be harnessed
to produce useful work? Etc. etc. Think Honest Roberts think! If you
are the only Great Theoretician on the sinking ship (John Baez and
others left and are now looking at you in amazement), your
responsibility is enormous.

Pentcho Valev