[time-nuts] UTC

Rob Seaman seaman at noao.edu
Mon Jul 25 15:39:09 EDT 2005

Poul-Henning Kamp says:

> Other people think that by sheer majority of users, the UTC  
> timescale no longer belongs to the astronomers, and that it can and  
> should be redefined to serve its major target audience better.
> You _really_ need to get out more...

I did get out more.  I've been focusing on two other issues entirely  
since scribbling that message.  In the week or so since the message I  
was replying to was written, there have been dozens of other things  
going on.  I  will continue to return to UTC since it is an ongoing  
problem.  Glancing over my message, I regret deciding to throw  
together a response - but it is hard to find time to give every issue  
the time it deserves to polish one's responses.

That said, are you of the opinion that your limited perception of my  
project list (or social calendar, for that matter) has anything at  
all to do with resolving technical issues?  As you say, some fraction  
of the people interested in the topics of the definition and  
transport of civil time believe that UTC is a throwaway time scale  
that should be sacrificed for the greater good.  Believing this does  
not make it so.

Let me reiterate my core assertions:

1) Civil time is a subdivision of the calendar and is thus a  
representation of time-of-day.

2) That said, one could imagine basing civil time on some time scale  
other than UTC.  This is a policy question that should be addressed  
forthrightly, not via a tricky initiative involving a mid-level  
bureaucratic committee.  We aren't just talking about leap seconds,  
we are talking about the definition of the concept of the "day".   
This is a potentially explosive political, legal and religious  
issue.  Its current obscurity should not be taken for granted.

3) Whatever time scale civil time is based upon, the integrity of the  
underlying time scale should be respected.  UTC has an existence  
separate from the ITU.  It should be maintained whether or not civil  
time continues to correspond to UTC.

4) The real issue is the improvement of systems, data structures, and  
APIs used to transport time signals corresponding to multiple time  
scales.  The current proposal is as much an attempt to sweep this  
important work under the rug, as it is an attempt to avoid subjecting  
non-conforming systems to the horrors of leap seconds.  Shame on  
anyone who is looking for an easy way out.

Time is complex.  Embrace the complexity.

Rob Seaman

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