[tz] The case against time zones

John Haxby john.haxby at oracle.com
Wed Aug 13 09:30:21 UTC 2014

On 08/08/14 14:32, Patrice Scattolin wrote:
> On 07/08/2014 4:52 AM, Lester Caine wrote:
>> It's only now we have a stable time source that we see the problem ...
>> and that is perhaps because someone got the duration of a second
>> wrong? Add a few more cycles to a second as they would have done 100
>> years ago by resetting the Greenwich clock :) 
> No, it's the length of the earth day that is changing over time as
> earth's rotation slows due to natural forces.
> http://www.washingtonpost.com/national/health-science/why-in-the-jurassic-era-an-earth-day-may-have-been-only-23-hours-long/2013/09/23/a75c548a-f2dc-11e2-ae43-b31dc363c3bf_story.html

Although it hasn't happened yet, it's possible to have a negative leap
second: 59 seconds in a minute to correct a time.  Although the long
term trend is for days to get longer, in the shorter term the length of
the day is chaotic and can go up or down.  Much like stock prices :)

Adding "a few cycles to a second" is not a sensible option.  Both NIST
(US) and the NPL (and the UK) would argue eloquently about that.  ("The
second is the duration of 9 192 631 770 periods of the radiation
corresponding to the transition between the two hyperfine levels of the
ground state of the cesium 133 atom.")


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