The Earth is expected to have a 25 hour day in 200 Million years. https://www.express.co.uk/news/science/741074/25-hour-day-earth-orbit-slowing Dividing by the number of seconds in an hour (3600) gives us 55,555.556 years until every day is 24 hours and 1 second long. Dividing by the number of days in a year gives us 152.20 years until we need 1 leap second every year. So after several decades from the reference year we are doing a leap second about every 3rd year, so about 78? 1950? 12 leap seconds would be 1826.48 years until we need 1 leap second per month. All subject to orbital variations.
On Fri, Sep 14, 2018 at 2:39 PM Paul Gilmartin <[email protected]> wrote: > > On Fri, 14 Sep 2018 09:14:25 -0700, Charles Mills wrote: > > >I believe that is in fact in the standard. > > > The best I easily find is: > https://www.iers.org/IERS/EN/Science/EarthRotation/UTC.html > ... > UTC is defined by the CCIR Recommendation 460-4 (1986). It differs from > TAI by an integer number of seconds, in such a way that UT1-UTC stays > smaller than 0.9s in absolute value. The decision to introduce a leap > second > in UTC to meet this condition is the responsibility of IERS (Bulletin C). > According to the CCIR Recommendation, first preference is given to the > opportunities at the end of December and June, and second preference to > those at the end of March and September. Since the system was introduced > in 1972 only dates in June and December have been used. > > I don't see any mention of more than 12 leap seconds within a year. I'd > rather > expect up to every month, then half-month, then daily, then hourly. A > 62-second > minute would be a desperate last resort. > > The ANSI C standard generously, or probably naively allows 62-second minutes. > > UTC1-UTC grows quadratically so it'll happen sooner than you expect. > https://en.wikipedia.org/wiki/%CE%94T > (I guess that's a parabola.) > > >-----Original Message----- > >From: Mike Schwab > >Sent: Friday, September 14, 2018 7:37 AM > >> > >> ... The UTC specification deals with that by requiring the value > >> 23:59:60.xxx during a leap second. The sequence of events is > >> well-determined. > > > >So, after a few thousand years and all days have 23:59:60 we will > >start having leap days lasting until 23:59:61? > > -- gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
