On 11-10-14 09:44 PM, Harry Veeder wrote:
On Fri, Oct 14, 2011 at 2:50 PM, Stephen A. Lawrence<sa...@pobox.com> wrote:
Using clocks in another frame (the GPS clocks) to synchronize the clocks in
the rotating frame (on the surface of the earth) just adds confusion, it
doesn't avoid the problem, which is fundamental. In particular, if you sync
your (rotating) clocks with an external source, then when you measure light
speed you find it's anisotropic -- it's faster one way than the other.
Why is that NECESSARILY wrong or confused?
It's not. There are perfectly fine coordinate systems in which SOL is
anisotropic, but they're hard to work with.
Note that in Einstein's original 1905 SR paper he said, rather
confusingly, that he was going to *define* the speed of light to be
isotropic. (Or, more precisely, he said the one-way travel time was "by
definition" half the two-way travel time -- but it amounts to the same
thing.)
It seems to that the "reality" of the constancy of speed light is more
like a preference than an absolute truth of existence.
Sure, but if you then *assume* that it's isotropic, without measuring
it, and you're working with coordinates in which it's not, you'll get
wrong answers.
