[time-nuts] Re: The SI second and the ease of realization (was: leap seconds finally being retired?)

[Poul-Henning Kamp]

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Magnus Danielson via time-nuts writes:

> This however keep changing. We see how sub 1 ns is more reachable, and 
> 100 ps is closer to availabile with commercial needs. Optical frequency 
> comparison is regularly done with 1E-19 level of performance, [...]

If optical clocks actually shone light, you could point the light
from two of them at a screen, and use the resulting pattern of
interference fringes to align them to the same exact height :-)

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