[LEAPSECS] leap second roundup 2017

[GERRY ASHTON]

> On October 23, 2017 at 1:37 PM Brooks Harris <brooks at edlmax.com> wrote, in part:
> 
> The irreconcilable difficulty arises from UTC being a modification of 
> the Gregorian calendar algorithm. The world (mostly) uses Gregorian, but 
> then along comes this unpredictable and irregular Leap Second to upset 
> the apple cart. No clever algorithm can fit that 86401th second label 
> (23:59:60) back into the Gregorian 86400-second-day. The Leap Second 
> must go, and so it does, either by ignoring it or smearing it, thereby 
> creating many incompatible and inaccurate timescales in the real world.

Subdivisions of a day are not part of the Gregorian calendar. What is part of the Gregorian calendar is that it is based on actual observations of solar days. Thus, if time scales based on the SI second with no leap seconds or equivalent adjustments are used, such as Terrestrial Time, and these time scales are extended far enough into the past or future that the difference between atomic days of 86400 SI s and observed days is on the order of a day, then it is not valid to describe these SI-second-based days as Gregorian calendar dates.

If you accept the argument that different concepts should be described with different names, then not only do we need a name other than UTC for the proposed continuation of UTC but without leap seconds, we also need a new name for the calendar.