[154423] in North American Network Operators' Group
Re: F-ckin Leap Seconds, how do they work?
daemon@ATHENA.MIT.EDU (Majdi S. Abbas)
Tue Jul 3 18:46:15 2012
Date: Tue, 3 Jul 2012 18:45:27 -0400
From: "Majdi S. Abbas" <msa@latt.net>
To: Tony Finch <dot@dotat.at>
In-Reply-To: <alpine.LSU.2.00.1207032329270.22150@hermes-2.csi.cam.ac.uk>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Tue, Jul 03, 2012 at 11:33:22PM +0100, Tony Finch wrote:
> Keith Medcalf <kmedcalf@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
