On Thu, Sep 10, 2009 at 6:56 PM, Raul Miller <[email protected]> wrote: > Ok, but... does this "leap second" occur outside of > any normal hours and minutes? Or does the last minute > of the last hour of the day last for 61 seconds?
The latter, and it's the last minute of the last hour of an UTC day, which is usually a minute in some other time of the day in most timezones. Also, in theory there can exists reverse leap seconds which means there's a 59 second long minute, but this has not yet occured (I think) in the few decades since leap seconds were introduced. Leap seconds are required because our atomic clocks are actually more reliably precise than the rotation of earth, but we want UTC midnight to be aligned to the rotation of earth (at least approximately) even if this rotation is not completely uniform or predictable. Ambrus ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
