[LEAPSECS] USWP7A docs for 2013 September meetings

[Poul-Henning Kamp]

In message <CACzrW9DfA5A+Zpfj=EkQoy2ft1qfim=cvGSMBYWD2mqtncKt0w at mail.gmail.com>
, Stephen Colebourne writes:


>The easiest way to eliminte them is to remove them. However, I differ

>from Poul-Henning however in that I don't find it palatable to ignore

>the fact that humans define days by the Sun.


I certainly don't ignore that.

Quite the contrary, I spent some time researching exactly what that
means.

The result was that most humans live perfectly comfortable lives
with the sun being 1-1.5 hours "off" from solar time, due to timezones
and daylight savings times.

China is particularly interesting:  It's only one single timezone,
despite the country being 5 timezones wide.

People don't live on UTC either:  People live on local timescales,
based on UTC, which add or subtract an offset to put the sun roughly
at south at noon.

These offsets have a granularity of about an hour, and many places
change twice a year, to put the noon-sun a more convenient place
than south for part of the year.  (BTW: It'll be interesting to see
how increasing global temperatures will affect DST policies.)

It follows quite obviously that the +/- 1 second DUT1 limit is
unnecessary for the "humans define days by the Sun" aspect,
a tolerance of +/-1 hour is not even required.

Therefore it is a perfectly valid long-term solution to decouple
UTC from the sun-angle, and instead compress all such considerations
into the UTC-offset of local timezones.

This has the added benefit of putting the issue under local
politcal control, rather than have a bunch of autocratic scientists
and barely representative telco people decided for all of humanity.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.