Re: [LEAPSECS] floating prime meridian

From: John Cowan <>
Date: Thu, 31 Aug 2000 20:28:52 -0400 (EDT)

On Thu, 31 Aug 2000, Rob Seaman wrote:

> The naive nature of my argument was the point, of course. I don't
> really expect any significant international confusion about the prime
> meridian (although my previous argument about the international date
> line may not be so theoretical).

AFAIK the date line is not defined as such: it is simply a theoretical
construct which depends on various nearby jurisdictions' definition of
what day it is, and it moves when they change their minds.
Sort of like the U.S. center of population, the location of which
depends solely on where people are living at any time.

> But we aren't really discussing a
> scientific or purely technical issue. We are discussing modifying
> the civil definition of the day, not just the proposed retirement of
> a technical entity called the leap second.

But what is the civil definition of the day? Is it:

a) 86400 SI seconds on most days, 86399 or 86401 seconds on days when
IERS says so; or

b) 86400 SI seconds on most days; on certain days of the year, enough
seconds to bring UTC and UT1 within 0.9 second of each other.

> But it isn't just the meaning of the wording "general equivalent" that
> needs to be reconsidered, it is the civil population's definition of time.
> A naive definition, sure, but are the advocates of the abolish leap second
> movement (whoever they are) going to include the contingent costs in their
> planning of reeducating 6 billion people?

What re-education? Mostly either 1) they need to be re-educated about
leap seconds every time there is one, or 2) they have absolutely no
interest in the subject. In any event, people who care only about
civil time may well be willing to trade off certainty for astronomical accuracy.

Complaints similar to yours were probably heard when the Romans
standardized the length of the month and decided to treat the phase of the
Moon as irrelevant. :-)

John Cowan                         
"[O]n the whole I'd rather make love than shoot guns [...]"
        --Eric Raymond
Received on Thu Aug 31 2000 - 16:44:51 PDT

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