> ........
> That's not quite how it works: the uncertainty principle relates
> pairs of observables. Even though knowledge of both speed and
> location is subject to the uncertainty principle, it is still
> the case that the speed of a photon may be determined with
> arbitrarily small uncertainty (in theory).
> ........
The Speed of Light is a constant depending on who's doing the measuring :-
Taken from "Electromagnetic Distant Measurement" by C.D. Burnside
(no URL, I actually got it from a real book)
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Person Date Velocity (km/s) Method
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Romer 1676 214000 Eclipses of Jupiter satellites
Bradley 1726 301000 Aberration of stars
Fizeau 1849 313000 Terrestial, wheel modulation
Rusa & Dorsey 1906 299784 +/- 10 Ratio of electromagnetic to electrostatic units
Michelson 1927 299796 +/- 15 Rotating Mirror device
Michelson & ors. 1933 299774 +/- 04 Rotating Mirror, mile long tube
Anderson 1940 299776 +/- 06 Kerr cell device
Birge 1941 299776 +/- 04 Weighted mean of past results
Essen & ors. 1947 299792 +/- 04 Cavity resonators
Aslakson 1949 299792 +/- 02.4 Radar measurements
Aslakson 1951 299794.2 +/- 02.4 Radar measurements
Bergstrand 1949 299793 +/- 02 Kerr cell - Geodimeter device
Bergstrand 1951 299793.1 +/- 00.2 Kerr cell - Geodimeter device
Essen 1950 299792.5 +/- 01 Cavity resonators
Froom 1954 299792.7 +/- 00.3 Microwave interferences
Scholdstrom 1955 299792.4 +/- 00.4 Kerr cell device
Ordnance Survey 1956 299792.4 +/- 00.5 Geodimeter 4, Ridgeway base
Froom 1957 299792.5 +/- 00.10 Microwave interferometer
................................................................................................
Accepted value 1973 299792.485 +/- 1.2 km/s
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Apparently that "arbitrarily small uncertainty" is 1.2 km/s.
As far as I know the 1973 value hasn't been updated.
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Hakeeb A. Nandalal
nanco@trinidad.net
"Divine intervention is unlikely"
- The Doctor, ST Voyager
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