From Brian.Inglis@Shaw.ca Thu Dec 22 18:51:56 2022
From: Brian Inglis <Brian.Inglis@Shaw.ca>
To: tz@iana.org
Subject: Re: [tz] [PROPOSED] Mention the planned obsolescence of leap seconds
Date: Thu, 22 Dec 2022 11:51:34 -0700
Message-ID: <aa2c03f9-d524-83a2-d8a3-a16dcabeb851@Shaw.ca>
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On 2022-12-20 17:25, Paul Eggert via tz wrote:
> +  Changes to commentary
> +    Note that leap seconds are planned to be discontinued by 2035.

> +    This affects time stamps during the leap second era (1972&ndash;2035).

> +Leap seconds were introduced in 1972 to accommodate the
> +difference between atomic time and the less-regular rotation of the earth.
> +Unfortunately they caused so many problems with civil

Civil (e.g. legal etc.) time keeping is not the problem, it is mainly=20
proprietary computer systems and applications, not adequately programmed to d=
eal=20
with the realities of time keeping.

> +timekeeping that they
> +are <a href=3D"https://www.bipm.org/en/cgpm-2022/resolution-4">planned
> +to be discontinued by 2035</a>, with some as-yet-undetermined
> +mechanism replacing them, perhaps after the year 2135.
> +Despite their impending obsolescence, a record of leap seconds is still
> +needed to resolve timestamps from 1972 through 2035.

I would expect astronomers and physicists to have divergent views, but both u=
se=20
software which handles varieties of time bases, scales, and conversions.
It seems likely that other scientists and disciplines with time concerns woul=
d=20
line up behind one or the other, depending on whether their focus is civil,=20
geocentric, or longer term in some way, or more artificial on accuracy,=20
calibration, precision or other short term characteristics.

>  <a href=3D"https://www.ucolick.org/~sla/leapsecs/"><abbr>UTC</abbr>
>  might be redefined
>  without Leap Seconds</a> gives pointers on this
> +contentious issue.
> +The General Conference on Weights and Measures
> +<a href=3D"https://www.bipm.org/en/cgpm-2022/resolution-4">voted in 2022</=
a>
> +to discontinue the use of leap seconds by 2035, replacing them with an
> +as-yet-undetermined scheme some time after the year 2135.

Expect every lawyer, in any case involving time stamped records, to jump on t=
he=20
technicality of any significant deviation of time keeping from solar time, wh=
ich=20
is the legal basis in most English common law jurisdictions, possibly also in=
=20
some continental code and Scandinavian/Nordic jurisdictions e.g. Denmark:

https://www.dr.dk/nyheder/indland/uret-paa-din-telefon-viser-en-ulovlig-tid

https://www-dr-dk.translate.goog/nyheder/indland/uret-paa-din-telefon-viser-e=
n-ulovlig-tid?_x_tr_sl=3Dda&_x_tr_tl=3Den

--=20
Take care. Thanks, Brian Inglis			Calgary, Alberta, Canada

La perfection est atteinte			Perfection is achieved
non pas lorsqu'il n'y a plus rien =C3=A0 ajouter	not when there is no more to=
 add
mais lorsqu'il n'y a plus rien =C3=A0 retirer	but when there is no more to cut
			-- Antoine de Saint-Exup=C3=A9ry

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