[LEAPSECS] What's the point?

Daniel R. Tobias dan at tobias.name
Tue Feb 15 08:16:17 EST 2011

On 15 Feb 2011 at 11:28, Poul-Henning Kamp wrote:

> So everybody using NTP and deriving GMT withut applying DUT are in

> breach of the law ?

Technically they are, if they use such a time for legal purposes (as
opposed to just privately having it on their wall or PC, where nobody
can force anybody to have any particular time). However, for almost
all purposes, the difference is "de minimis", since fractions of
seconds rarely matter except in highly specialized fields.
(Fractions of seconds in absolute time, that is; a somewhat larger
set of fields care about such time intervals in relative time, such
as sports events where timing to the tenth or hundredth of a second
matters, but that's done by stopwatches that don't need any sort of
synchronization to UTC, GMT, or any other external standard, though
the seconds they tick off need to be made as close as possible to the
duration of SI seconds.)

One would have to work hard to contrive an issue where the difference
actually matters for the purpose of a legal proceeding, like by
managing to submit some legally mandated thing with a deadline in the
tiny interval between a specified time in UTC and GMT (construed as
UT1) and then getting into a court case about it.

Last year, there was a bit of an internal flap within American Mensa
when one of the candidates for an office within the organization was
disqualified from the election because his candidacy petition was
submitted a few minutes past the deadline (according to the local
time zone where the national office was located), even though that
candidate's place of residence was in a different time zone to the
west of it, and it was still before the deadline over there, and the
sloppily drafted election rules didn't actually explicitly specify
what time standard was to be used. No court case resulted, though.
I don't know if even Mensans would split seconds to create
controversies of this sort, however.

However, if UTC were to be completely unmoored from GMT/UT1, the
difference would grow, and the likelihood of actual issues arising
from it would vastly increase.

== Dan ==
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