[LEAPSECS] "China move could call time on GMT"
Clive D.W. Feather
clive at davros.org
Mon Jan 9 04:30:15 EST 2012
Warner Losh said:
>> More to the point the entire notion of playing musical chairs with the worldwide timezone system
> An hour every 10 years is 360 seconds a year, which is 20x faster than UTC can tolerate as it is defined today.
Let's turn it around. UTC as defined today can cope with up to one leap
second per month, or 12 per year. Any alternative proposal therefore needs
only cope up to that limit as well (otherwise we are comparing apples with
oranges or, if you prefer, are tilting the playing field).
12s/yr is 1 hour every 300 years. Therefore the "musical chairs" involves a
*possible* change every several lifetimes.
To put this in perspective, in the UK we're talking about further away than
the introduction of the Gregorian Calendar with its 11 day shift and two
consecutive years of unnatural length (282 and 355 days). In half that
period we've moved from local mean solar time to GMT to summer time to
double summer time to back again to BST to summer time again to something
like 11 different rules for the shift date to a proposed permanent one-hour
change for political and economic reasons even though it takes us *away*
from the sun.
If paying the price of an additional one-hour shift in 12 generations time
is the price to pay for getting rid of leap seconds, I'd happily pay it in
> It all comes down to what time on the clock should tell us: earth angle (eg, where the sun is) or elapsed time since an epoch. This whole issue boils down to that.
Indeed. But Rob *defines* time as earth angle and then tries to tell us
we're breaking the whole world.
Clive D.W. Feather | If you lie to the compiler,
Email: clive at davros.org | it will get its revenge.
Web: http://www.davros.org | - Henry Spencer
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