Re: [LEAPSECS] how posterity will measure time

From: Ed Davies <>
Date: Mon, 04 Dec 2006 23:27:59 +0000

Rob Seaman wrote:
> ...
> An amateur astronomer with a Celestron, the Astronomical Almanac
> and an atlas can recover UTC anywhere on Earth.
> ...

Do you really mean UTC here? I can see that an amateur with a
Celestron could recover UT (for some flavour of UT, I'm not sure
which - UT0?, then presumably UT1 after traveling around a bit)
but where does the delta T come from to get UTC?

> ...
> Unplug the atomic clocks for a few seconds (which may be taken as the
> definition of a "discontinuity in higher civilization"), and even the
> professional timekeepers who built the devices would be unable to
> recover TAI.
> ...

Actually, assuming somebody remembered to make a note of
TAI-UTC before forgetting to put a shilling in the meter for
the atomic clock TAI is exactly as recoverable as UTC in the
short term when it's possible to work out the number of leap
seconds which would have been inserted or removed. Longer
term it would be harder, of course, but why would that matter?

Received on Mon Dec 04 2006 - 15:28:46 PST

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