On Mon, 2017-01-09 at 13:41 +0100, Preben Nørager wrote: > On Tue Jan 3 14:18:52 EST 2017, John Sauter wrote: > > "I regard leap seconds as a reasonable compromise between the needs > of civil time and of science. Civil time needs a clock that tracks > the days and the seasons. Science requires a clock that measures time > in precise intervals. UTC provides both, using leap seconds to keep > atomic time synchronized with the rotation of the Earth." > > I think there is something wrong with that argument. Civil > timekeeping holds both a clock, and a calendar. The calendar track > the seasons, while the clock track the time. If it is to be said, > that the clock track the days, it is important to notice the > difference between apparent time, and mean time. The clock track > either the sun (apparent time), or the seconds (mean time). > > When the Nautical Almanac in 1833 substituted mean for apparent solar > time, an important step was taken. From now on chronometry was to > rely on mechanical clocks, and with the invention of atomic clocks, > the tracking of the 24-hour day (86400 international seconds) can now > happen without any daily tracking of the sun. > > The question really is whether the calendar needs the daily tracking > of the sun or not. And the answer to that question obviously depend > upon which calendar we want! > > I think the disagreement about leap seconds, really is a disagreement > about which calendar to use for civil timekeeping. If we agree to use > the proleptic gregorian calendar (ISO 8601) there is really no need > for leap seconds. That calendar track the seasons well, and with the > slight modification, to add the additional rule that years evenly > divisible by 4000 are not leap years, it would track them even > better. > > Leap seconds are really only a need for those who do not want to see > the proleptic gregorian calendar become universal. For instance for > those who want to use the julian period, as the basis for one > calendar or another, because they must somehow rely on apparent time, > and not mean time, because the julian period count apparent solar > days. > > Let us use ISO 8601, and abolish leap seconds all together.
ISO 8601 handles leap seconds perfectly well. In ISO 8601 format, the
most recent leap second was named 2016-21-31T23:59:60Z.
I don't understand what you mean when you say "Leap seconds are really
only a need for those who do not want to see the proleptic gregorian
calendar become universal." I would have no objection to the proleptic
Gregorian calendar becoming universal (though I would not force it on
anyone who did not like it) and yet I am a supporter of leap seconds.
John Sauter (john_sau...@systemeyescomputerstore.com)
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