[LEAPSECS] Future time

[Tony Finch]

Warner Losh <imp at bsdimp.com> wrote:

> On Jan 18, 2014, at 1:52 PM, Stephen Scott wrote:



> > The basis of my understanding is that UTC is a timescale that:

> > -    progresses at a rate of the second (SI) and has done so since 1972-01-01.

> > -    is expressed as a count in the form of date, hours, minutes and seconds;

> > -    is continuous other than the discontinuities resulting from leap second corrections;

>

> To pick a pedantic nit: It is continuous. No "other than". UTC is a

> continuous time scale. It has a non-uniform radix that is expressed at

> the leap seconds when its rules for labeling seconds changes slightly to

> label the leap second 23:59:60. The timescale has a discontinuity when

> there's a phase jump. UTC does not have phase jumps, even if it chooses

> a non-traditional time to label some of its seconds once every year and

> a half or two.


I think it is reasonable to say that UTC's labelling of seconds is
discontinuous. For timescales that use simple ancient sexagesimal notation
you can write down some straightforward formulae mapping between a count
of seconds and a broken down time. If you try to do the same for UTC you
have to write down something that is piecewise linear with exceptions. It
isn't a continuous map like other timescales.

Tony.
-- 
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