F-ckin Leap Seconds, how do they work?
Majdi S. Abbas
msa at latt.net
Tue Jul 3 22:45:27 UTC 2012
On Tue, Jul 03, 2012 at 11:33:22PM +0100, Tony Finch wrote:
> Keith Medcalf <kmedcalf at dessus.com> wrote:
> >
> > You are assuming facts not in evidence. The rotation is merely
> > irregular within the capabilities of our scheme of measurement,
> > calculation, and observation.
>
> There is LOTS of evidence that the earth's rotation is irregular. VLBI,
> laser ranging of the moon, etc. This was known long before the atomic
> clock was invented, and it is why the definition of the second was changed
> from one based on earth rotation to one based on Newcomb's ephemerides,
> before the change to an atomic second.
This.
Shoot, seismic activity has a measurable effect. The best we
can do is approximate it and align the timescales as needed. There's
no lack of understanding here, just a changing planet.
Now, changing your kernel's leap second handler and not
testing it, well, you can't blame that one on the ITU or the
aforementioned planet.
--msa
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