Rob van der Putten wrote:
> Quadibloc wrote:
>
> > Yes, this is quite right. However, while the second is no longer
> > defined in terms of a fraction of the tropical year in 1900, the
> > Earth's rotation still factors in to this in a more subtle way.
> >
> > You see, the Earth is in *motion*. And the SI second is defined (in
> > practice, within the framework of UTC) as so many vibrations of a
> > cesium atom...*sitting on the Earth*. So what was being referred to in
> > what you are quoting is _not_ time being defined in terms of the
> > Earth's motion, instead of being atomic time (the poster works for
> > NIST, and has authored several papers on the atomic time scale) but
> > the fact that our current time scale doesn't include *relativistic
> > corrections* for the Earth's motion.
>
> I suppose one would have to apply a correction for the movement of the
> solar system through the galaxy as well. And the movement of our galaxy
> through the universe.
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