Re: [LEAPSECS] two world clocks

From: John Cowan <jcowan_at_REUTERSHEALTH.COM>
Date: Thu, 20 Jan 2005 17:24:41 -0500

Rob Seaman scripsit:

> What exact future systems are we discussing that will both 1) require
> the use of Universal Time and 2) not require a definition of Universal
> Time that is tied to the rotating Earth?


LCT is currently tied to UTC, and converting a count of SI seconds to
a UTC time is currently (a) annoying and (b) depends on updating tables.

> Attempting to move the entire worldwide civil time system to a
> non-Earth based clock is equivalent to attempting to build a clock
> designed to run untended for 600 years - in effect, to attempting to
> build a millennium clock. The alarm must be designed to ring in 599
> years time.

This is simply not true. The LCT-TI offsets can be adjusted locally as and
when they individually start to be a problem. No global changeover is required.

> Systems that don't need time-of-day should use TAI.

Wall clocks need to run in LCT, which is currently founded on UTC. Most people
don't need precision time-of-day (which should be rightly called "Earth angle"
and measured in SI radians). They just need there to be a rough correlation
between LCT and the sun, and several hours' discrepancy can be tolerated.
Just go to Urumqi, or Detroit if Urumqi is too remote.

> And most definitely, let's stop these inane and embarrassing closed
> door discussions among biased insiders.

Personally, I am a biased outsider.

> It ain't your clock - it's *our* clock.

Eh? Who are "you" and who are "we"?

Not to perambulate                 John Cowan <>
    the corridors        
during the hours of repose
    in the boots of ascension.       --Sign in Austrian ski-resort hotel
Received on Thu Jan 20 2005 - 14:24:54 PST

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