[LEAPSECS] it's WP7A week in Geneva

[Rob Seaman]

Poul-Henning Kamp wrote:


> And you have repeatedly tried to ignore the question of how large  

> the civil-solar tolerance is, can or should be.


I don't think a fair and impartial witness would say given my plethora  
of messages over the years that I've ever successfully ignored  
anything :-)

That said, a one-hour tolerance is many orders of magnitude too large,  
see previous threads.


> But maybe part of that problem is in the moniker "civil time", which  

> we have never fully agreed what means ?


What I mean is "the common international timescale that underlies  
local time worldwide for everyday purposes".


> How about we operate with _three_ kinds of time and one kind of  

> geophysics:


Certainly one geophysics - that's the point of tying the standard to  
physical reality rather than to racks of equipment demanding constant  
attention and robust interconnects forever.

There are many more than three kinds of time, but I believe previous  
discussions have uncovered no reason for layering the civil  
timekeeping standard and infrastructure on more than the two that UTC  
already references.  There are plenty of degrees of freedom to find  
alternate solutions that actually address the requirements.


> If any national government wants to do something stupid to human  

> time in their country, nobody can prevent them from doing so.


Which is why underlying physical reality has to fill that role.  Also,  
what exactly would an isolated "human time in their country" actually  
mean?  Every day for everyone, our activities are connected to those  
of humans and systems in other time zones.  There is one international  
community and there must be one common timescale.


> astronomers pointing their telescopes, but do you have any other  

> argument than that ?


As stated many times, astronomers are power users for more kinds of  
time (in more bizarre places) than anybody else.  We certainly use  
both atomic and mean solar timescales.

This discussion is about civil timekeeping.

Rob