[time-nuts] de Witte's Experiment

Tom Van Baak tvb at LeapSecond.com
Wed Aug 28 20:05:32 EDT 2013


> I wonder if the effects caused by a different distance from the Sun between day and night,
> and hence a different gravity field were taken into consideration.
> After all, a greater gravity field causes time to flow slower with respect to absence of gravity.
> 
> 73  Alberto  I2PHD

Alberto,

That's correct. The twice daily, daily, monthly, annual changes in gravity that we see here on earth (lunar/solar tides) create surface elevation changes on the order of half a meter. The frequency of an atomic clock changes by about 1e-16 per meter of elevation so you're looking at a net effect down in the -17's; a value that's still too small to measure.

Note that tides have no effect on co-located atomic clocks since they all rise and fall together. For best effect you'd want to compare clocks that are about 90 degrees longitude apart, such as US vs. EU. But then you have unsolved time transfer stability issues.

If you want to measure the effect of gravity/tides on time, use a pendulum clock; they are much more sensitive to changes in gravity than atomic clocks:
http://leapsecond.com/hsn2006/

If you must use an atomic clock, this is still the easiest way to go:
http://leapsecond.com/great2005/

/tvb




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