Re: [LEAPSECS] when the media comes a knocking

From: John Cowan <>
Date: Mon, 28 Jul 2003 15:02:36 -0400

Steve Allen scripsit:

> Supposing that this might happen again, here's something to have handy:

This is a nice, if tendentious, summary. However, I have to take exception
to this:

> At Torino the proponents of omitting leap seconds supposed that the
> governments of the world might handle this situation using leap hours
> introduced into civil time by occasionally omitting the annual ``spring
> forward'' change to jump to summer/daylight time. However there are
> serious questions raised by the notion of a leap hour. Given that the
> first leap hour would not happen for centuries, it is not clear that any
> systems (legal or technological) would build in the necessary complexity
> for handling it.

Au contraire. Leap hours are precisely changes in the difference between
LCT and the universal reference time (as opposed to leap seconds, which
are discontinuities in the reference time itself). Existing systems must
already handle this, and must allow, in certain parts of the world, for
the fact that *when* the shift occurs is not foreseeable. In Israel,
for example, the start and end of DST is fixed annually by an act of
the Knesset, and is not predictable. The statement "I'll meet you in
Jerusalem at noon on <day>" does not have a fixed meaning in terms of
either time-of-day or interval time, if <day> is more than a year away.

John Cowan
"If he has seen farther than others,
        it is because he is standing on a stack of dwarves."
                --Mike Champion, describing Tim Berners-Lee (adapted)
Received on Mon Jul 28 2003 - 12:04:35 PDT

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