Re: Does motion affect the operation of clocks or not ?

Andrew Harland wrote:

Hi everybody

In his paper - "The Confrontation between General Relativity and
Experiment: A 1998 Update" - http://xxx.lanl.gov/abs/gr-qc/9811036
Clifford M. Will wrote on page 12 that
the Global Positioning System (GPS) provides absolute
accuracies of around 15 m (even better in its military mode)
anywhere on Earth, which corresponds to 50 nanoseconds in
time accuracy at all times. Yet the difference in rate between
satellite and ground clocks as a result of special and general
relativistic effects is a whopping 40 microseconds per day
(60micros. from the gravitational redshift, and -20micros. from
time dilation). If these effects were not accurately accounted
for, GPS would fail to function at its stated accuracy.

This seems to indicate that the GPS clocks are really affected by
motion. However, in their book "Spacetime Physics - Introduction to
Special Relativity" (W. H. Freeman and Company - 1992) Edwin F.
Taylor and John Archibald Wheeler write on page 77:
We conclude that free-float motion does not affect the
structure or operation of clocks.

I'm not sure what to believe now. Does motion affect the operation of
clocks or not? Can anybody enlighten me on this?

<http://relativity.livingreviews.org/open?pubNo=lrr-2003-1&page=node5.html>
Relativistic effects on orbital clocks

The clock that traverses the most space records the least time
elapsed.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

.

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