[ntp:questions] Re: GMT: UT1 vs UTC

David L. Mills mills at udel.edu
Thu Oct 30 16:49:58 UTC 2003


If we ever had to give back a leapsecond, it would be a disaster. The
WWV/WWVB timecode has only a single bit to signal leap insertion and no
way to signal deletion. The GPS timecode has the UTC-GPS offset in
seconds, but the GPS receivers I have indicate only leap insertion. From
the ERTS data the rate of increase has flattened out over the past thre
years, which certainly gives me the willies, but my professional friends
tell me not to worry about it.


Terje Mathisen wrote:
> Ian G Batten wrote:
> > Come the winter, for us in the UK date(1) reports:
> >
> > Thu Oct 30 11:01:15 GMT 2003
> >
> > when in fact for almost everyone's computers it's UTC, which is +/- 0.9s
> > from GMT.  And the `Greenwich Time Signal' on the radio is UTC(GPS)
> > these days, too.  Does anyone have a clock which actually ticks UT1?
> Why would you want one?
> Even in England/Great Britain GMT is just a local name for UTC these days.
> UT1 is for astronomers, as well as a way to figure out when/if to
> add/subtract leap seconds.
> BTW, anyone want to bet how much (supposedly leap-second handling) gear
> will fall down if we actually have to subtract a leap second?
> Terje
> --
> - <Terje.Mathisen at hda.hydro.com>
> "almost all programming can be viewed as an exercise in caching"

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