[LEAPSECS] Cheating means more planning, not less

Poul-Henning Kamp phk at phk.freebsd.dk
Sun Dec 28 18:05:19 EST 2008


In message <1FB1C7F7-95F4-450A-B823-349ABA3B8A77 at noao.edu>, Rob Seaman writes:


>The real observation is the familiar one of dual timescales. Focus on

>the SI second and we see the world through atomic eyeballs. Focus on

>the primacy of the definition of the day in civil timekeeping, and

>Earth orientation pops out.

>

>Both timescales are necessary.


It is well documented that the SI second based timescale has precision
and stability requirements on the order of microseconds for telecoms
and 10 orders of magnitude smaller for scientific tasks.

In contrast to this, nobody, including you, seem to be willing to
even hazard a guess what level of presision is required or sufficient
for the "earth orientation clock".

The current UTC definition says "better than one second", but relative
to an abstract definition of earth rotation angle which
only astronomers can figure out.

Emperical evidence show that most of the earths human population is
perfectly happy with local time that is within a couple of hours
of "proper" earth rotation time.

The fact that almost all people who have one, trust and rely on the
clock in their mobile phone, certainly much more than they do on
the lengths of shadows and shadows on sun-dials, is a credible
argument that no such requirement really exists, and that the
mechanism proposed bu ITU combined with country-by-country timezone
adjustments is a valid and solid solution.

Now, stop the red-tape machine Rob, and put some facts on the table.

Poul-Henning

--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.


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