[tz] [PROPOSED] Mention the planned obsolescence of leap seconds

Brian Inglis Brian.Inglis at Shaw.ca
Thu Dec 22 18:51:34 UTC 2022

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 (1972–2035).

> +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 
proprietary computer systems and applications, not adequately programmed to deal 
with the realities of time keeping.

> +timekeeping that they
> +are <a href="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 use 
software which handles varieties of time bases, scales, and conversions.
It seems likely that other scientists and disciplines with time concerns would 
line up behind one or the other, depending on whether their focus is civil, 
geocentric, or longer term in some way, or more artificial on accuracy, 
calibration, precision or other short term characteristics.

>  <a href="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="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 the 
technicality of any significant deviation of time keeping from solar time, which 
is the legal basis in most English common law jurisdictions, possibly also in 
some continental code and Scandinavian/Nordic jurisdictions e.g. Denmark:



Take care. Thanks, Brian Inglis			Calgary, Alberta, Canada

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

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