Re: [LEAPSECS] what should a time standard encompass?

From: Steve Allen <>
Date: Mon, 27 Jan 2003 11:49:18 -0800

On Mon 2003-01-27T13:53:56 -0500, John Cowan hath writ:
> Currently *everyone* (not just astronomers) has to depend on distributed
> leap-second information to just know what the local civil time is. That is
> a most unreasonable burden.

Yes, but the reasonable solution is to develop protocols that permit
the distribution of as many different forms of time as are deemed
useful, and then to educate time users to choose the time scale that
suits them best.

> We can't do anything about the summer-time part of it, because that depends
> on local political entities that can change their minds freely, but we
> can do something about the leap seconds, viz. stop tying civil time to them.
> The discrepancy between LCT and LMT is already in the multi-hour range
> for some locations, and a half-hour or even an hour difference is considered
> entirely normal.

The legislatures of the various Australian provinces recently modified
the legal definition of their summer time to suit the 2000 Olympics
with only about a year's advance notice. This was much to the chagrin
of users whose computers do not receive routine updates of their
summer time databases.

It would be just as easy for a legislature to assert that TAI become
the civil time standard. I find it specious to presume that the
legislatures of the world are incapable of making this sort of
decision. If the worldwide general consensus becomes to change civil
time to an unsegmented time scale, then the economic incentives for any
single legislature to switch to TAI are both strong and obvious. Most
of the clocks in the world would just as easily be reset by 1 hour and
32 seconds as they would by 1 hour, so there should be no technical
argument against switching to TAI during some summer time transition.

> I also care, as a practical matter, that the name "UTC", which is used
> in (almost all of) the world's civil time legislation, be kept for that
> purpose. Astronomers can very well switch to a different abbreviation for
> their |UTC - UT1| < 0.9 timescale.

Here be the crux. Some one or some agency is inevitably going to have
to take the public risk of proclaiming this decision.

Who are the parties making this decision? I suspect that they may
indeed fear the ridicule of posterity, for they appear to be setting
this process up as a multi-year initiative by multiple committees
whose membership is obscure, meetings to attend, and minutes published
in proceedings with low circulation and exorbitant price. It will be
hard to blame anybody for whatever result happens.

>From a social standpoint the goal should be to set up sufficient
advance preparation so that any change that occurs can be absorbed in
the natural costs of doing business for *EVERYONE*, not just for some.

Steve Allen          UCO/Lick Observatory       Santa Cruz, CA 95064      Voice: +1 831 459 3046
PGP: 1024/E46978C5   F6 78 D1 10 62 94 8F 2E    49 89 0E FE 26 B4 14 93
Received on Mon Jan 27 2003 - 11:49:33 PST

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