On 28/10/11 08:53, Tom Lane wrote:
> Gavin Flower<GavinFlower@archidevsys.co.nz> writes:
>> Actually, a minute is not always 60 seconds, as you can legally have 62
>> seconds in a minute!
> <pedantry>
>
> There never have been, and will never be, two leap seconds declared in
> the same minute --- the need for such would require that the authorities
> in charge of declaring leap seconds had been asleep at the switch when
> they should have declared the first one, and for awhile afterwards
> as well, since the natural spacing of such events is well over a year.
> Even if they did get that far behind, they would catch up by declaring
> *one* added leap second in several successive opportunities.
>
> The idea that there could need to be 62 seconds in a minute appears to
> stem from a typographical error in an ancient version of some Unix
> documentation or other (hardly a reference material for timekeeping),
> which has been faithfully copied into a bunch of later computer-oriented
> standards. But it's wrong, no matter how many places say that. Ask an
> astronomer rather than a computer scientist, if you're not convinced.
>
> </pedantry>
>
> regards, tom lane
Thanks for the explanation!
If we ever really needed the 62 second minute, and the timekeepers were
not sleeping on the job, it would be because of a catastrophic
geological event that would almost certainly mean that the survivors
would be having more pressing concerns... (major earthquakes affect the
speed of the Earth's rotation - microseconds in the case of the last
major Japanese earthquake)