"Clive D.W. Feather" wrote on 2005-01-20 12:34 UTC: > >> A resolution was proposed to redefine UTC by replacing leap seconds by leap > >> hours, effective at a specific date which I believe was something like > >> 2020. > > I may be wrong here, but I thought the "leap hour" idea did *not* insert a > discontinuity into UTC.
I think, the phrase "to redefine UTC by replacing leap seconds by leap hours" can only mean going from |UTC - UT1| < 1 s to something like |UTC - UT1| < 1 h (or some other finite |UTC - UT1| bound like that). That was certainly the idea of the BIPM proposal presented at the Torino meeting. > Rather, in 2600 (or whenever it is), all civil > administrations would move their <local>-UTC offset forward by one hour, > in many cases by failing to implement the summer-to-winter step back. Such a proposal would be called "to redefine UTC by eliminating future leaps" (i.e., by establishing a fixed offset between UTC and TAI). It seems perfectly practical, at least as long as |UTC - UT1| < 24 h (i.e., for the next 5000 years). What local governments with regional civilian time zones do is outside the influence of the ITU. But if leap seconds were eliminated from UTC and a fixed TAI-UTC offset defined instead, then what you describe above is indeed what I would expect to happen with most of them. Unless we give up the notion of local time zones entirely, there would be a clear need to keep them locked to UT1 + offset to within an hour or so. Markus -- Markus Kuhn, Computer Lab, Univ of Cambridge, GB http://www.cl.cam.ac.uk/~mgk25/ | __oo_O..O_oo__