[LEAPSECS] Nit-pick: SI second

[Steve Allen]

On Mon 2011-02-07T14:39:10 -0700, Warner Losh hath writ:

> >Are you sure you aren't confusing red shift (which has been

> >a known factor since the 60's) with blackbody shift (which

> >only arose in the 90's as clocks hit the 1e-15 level)?

>

> I may well be confused between the two...


Astronomically-speaking neither one has a relevant effect.

The IAU did not object when BIH/BIPM changed the rate of TAI by 1e-12
on 1977-01-01.  Whereas the SI second was based on the ephemeris
second, and the ephemeris second was originally specified to 1e-12,
the effect of the rate change amounts to 0.25 s over the entirety of
written human history.  No astronomical observation was ever likely to
distinguish the change.

--
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