[tz] Coordinated Universal Time (UTC) to retain “leap second”
Marshall Eubanks
marshall.eubanks at gmail.com
Fri Nov 20 18:31:21 UTC 2015
On Fri, Nov 20, 2015 at 1:12 PM, Steve Allen <sla at ucolick.org> wrote:
> On Fri 2015-11-20T12:55:49 -0500, Marshall Eubanks hath writ:
> > No, that will not work. The UTC clock is providing not just the time, but
> > also the rotation of the Earth (UT1). An atomic clock cannot do that (not
> > at the km level), and the tables cannot provide leap seconds (much) in
> > advance.
>
> The almanacs are tabulated only a couple of years in advance, and over
> that short an interval the current predictions of earth orientation
> have errors about the same as the typical human error using a sextant.
>
The USNO's MICA runs up to 2050, but of course does not include future UT1
variations.
> Full precision already needs the DUT1 = UT1 - UTC, so if the radio
> broadcast time signals and almanacs could arrange to agree on a new
> time scale then a new difference value would preserve that ability.
>
> Well, you could get WWV to announce UT1 - UTC offsets :)
But, then, you couldn't do celestial navigation off-shore with an FM or AM
radio.
Full disclosure, Marshall and I worked across the building from each
> other using VLBI to measure earth orientation, so take this discussion
> as an example of why the ITU-R could not forge a working compromise.
>
>
It does tend to give rise to discussion...
Marshall
> --
> Steve Allen <sla at ucolick.org> WGS-84 (GPS)
> UCO/Lick Observatory--ISB Natural Sciences II, Room 165 Lat +36.99855
> 1156 High Street Voice: +1 831 459 3046 Lng -122.06015
> Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mm.icann.org/pipermail/tz/attachments/20151120/4e1380f0/attachment.html>
More information about the tz
mailing list