On Wed, Feb 29, 2012 at 2:38 PM, Paul Gilmartin <[email protected]>wrote:
> On Wed, 29 Feb 2012 15:43:02 -0500, John Gilmore wrote: > > >Paul Gilmartin writes: > > > ><begin extract> > >STCKE is notionally closer to TAI than to UTC in that TAI and STCKE > >are continuous timescales and UTC is discontinous. TAI and STCKE both > >embody the notion of (micro)seconds since an epoch; UTC is specified > >in terms of yyyy mm dd hh mm ss.fraction with minutes varying in > >length as leap seconds occur. > ></end extract> > > > >Note quite. This formulation is plausible by analogy with the notion > >that the Gregorian Month of February, normally comprised of 28 days, > >is comprised of 29 days in leap years. > > > >Leap seconds, however, are inserted into UTC by the BIPM upon the > >recommendation of the IERS (Earth Rotation and Reference Systems > >Service); and they are conceptually and by definition > >extracalendrical. Neither 1) the last minute in June or the first > >minute in July nor 2) the last minute in December or the first minute > >in the subsequent January is lengthened when a leap second is inserted > >between them. [This decision was taken advisedly. There are a number > >of calendars---The Hebrew religious one is the obvious example---that > >make no use of minutes and/or seconds.] > > > And here, I'll disagree with you. The embolismic second is 23:59:60 > of the previous day. I've seen it flash by with a telnet connection > to NIST. (Or maybe they just had to call it something.) This seems > to me no more extracalary than February 29. But it's all highly > academic. > > By the way, the embolismic day in bissextile years is February 24, > the sixth day before the kalends of March. > My head is going to explode (one of these leap seconds; if I can pin down when and where it occurs) from learning all of these new words. ;-) > (Spellcheck hates us.) > > -- gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
