[LEAPSECS] Lets get REAL about time.

Rob Seaman seaman at noao.edu
Mon Jan 23 00:16:47 EST 2012

Warner Losh wrote:

> So I can't do operations on UTC time stamps that are more than 6 months in the future?

It depends what operations, and what a timestamp is deemed to mean. Currently UTC approximates UT; it is stationary wrt time-of-day. Myriads of human activities are diurnal and time-of-day is the pertinent timescale. Measuring future or past intervals in SI-seconds is beside the point for these use cases, an exercise in fitting a square peg in a round hole.

The plight will be writ large should the notion of timezone roulette be implemented. In that case, over the centuries it will be similarly unpredictable what timezone a particular country or province, state or city observes - will observe - or did observe at some past moment (without consulting some big book of timekeeping trivia). What is a curiosity currently, the adjustment of a timezone, would become commonplace and historians won't be able to "do operations" on UTC timezone offsets as Zefram noted:

>> Other direction. Paris's UT+1h would become TI+1h, then TI+0h, TI-1h, TI-2h, and so on. ("TI" meaning the no-leap-seconds time scale that succeeds UT in common use.)

Even the direction of drift will be a matter of debate as demonstrated on this list.


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