[LEAPSECS] leap smear

Poul-Henning Kamp phk at phk.freebsd.dk
Mon Sep 19 02:49:38 EDT 2011


In message <4CE6E012-A146-4E15-8F46-533186373B13 at noao.edu>, Rob Seaman writes:


>The meaning of civil time certainly has something to do with the

>rotation of the Earth.


Yes it does, just not very much.

Civil time is tied to Earth Orientation with a precision
of +/- N hours, for values of N up to about 5.

Civil time is tied to other governments notion of civil time with
of +/- < N nanoseconds, for values of N less than 100.

The "System Engineering" that went into this, clearly found it much
more important to be able to compare time in London to time in New
York, than to the position of the Sun and other celesial bodies.

--
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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