[ntp:questions] National time standard differences

Greg Hennessy greg.hennessy at cox.net
Thu Feb 11 22:25:44 UTC 2010

On 2010-02-11, David J Taylor <david-taylor at blueyonder.delete-this-bit.and-this-part.co.uk.invalid> wrote:
> Thanks, John.  Was the measurement down to the nanosecond level?

>From the abstract:
Around-the-World Atomic Clocks: Observed Relativistic Time Gains
J. C. Hafele 1 and Richard E. Keating 2

1 Department of Physics, Washington University, St. Louis, Missouri 63130
2 Time Service Division, U.S. Naval Observatory, Washington, D.C. 20390

Four cesium beam clocks flown around the world on commercial jet
flights during October 1971, once eastward and once westward, recorded
directionally dependent time differences which are in good agreement
with predictions of conventional relativity theory. Relative to the
atomic time scale of the U.S. Naval Observatory, the flying clocks
lost 59 ± 10 nanoseconds during the eastward trip and gained 273 ± 7
nanoseconds during the westward trip, where the errors are the
corresponding standard deviations. These results provide an
unambiguous empirical resolution of the famous clock "paradox" with
macroscopic clocks. 

The article is publised in:
Science 14 July 1972:
Vol. 177. no. 4044, pp. 168 - 170
DOI: 10.1126/science.177.4044.168

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