I'm pleased to see such a robust discussion - yet again. Some of the
posters are very familiar from previous rounds of discussion, some
names seem new to me. If there are new members of this list (and we
certainly could benefit from such - no irony intended), they may not
have stumbled onto the list archives:
http://rom.usno.navy.mil/archives/leapsecs.html
Many of the current talking points have been thrashed out over and over
again. It must surely be clear to everyone on all sides of this
decision that there is no consensus. In such a case what is the best
thing to do? I see two options. First, attempt to open the discussion
to a wider community who may be able to offer new perspectives on the
issues. This is the brave approach. Second, retreat to our separate
bunkers and lob verbal bombs at each other with the hope of eventually
"winning" the battle. Some might characterize this as the "prudent"
approach. I've surrounded "prudent" in quotes because I believe such a
strategy will eventually prove itself flawed not only to the losers of
the leap second battle, but to the winners.
You may disagree with my statements above. Clearly a large fraction of
the members of this list disagree with my point of view on other issues
:-) Just as nobody else has expressed an opinion that appears to be
shared by a majority of current list members. It's anybody's guess
what the folks on the standards committee(s) think. Why then do we
continue to focus on the places where we disagree?
I think there is at least one area that we all will agree deserves
further discussion. It is the area that for five years has been (at
least apparently) ignored by the powers that be. It seems to me that
this issue should be at the center of the decision making process
related to civil time, and of its past and future relationship to
Coordinated Universal Time and/or International Atomic Time. That
issue is:
How (precisely) can we improve the distribution of time signals to
the
worldwide communities that depend on them?
After all, the UTC standard is a discussion of the explicit details
involved in distributing a joint radio time signal that conveys TAI at
about the millisecond level and UT (UT1 to be precise) at the tenth
second level. (See comments below.) The fact is that the astronomers
already compromised on the precision of UT delivery - TAI benefits by
two orders of magnitude. Astronomers have long since demonstrated that
they are willing to compromise. Others need to do the same.
Surely a better mechanism (or mechanisms) could be designed for
conveying interval time and time-of-day worldwide. Surely the first
step for any project team handed such a daunting mandate would be to
spend a significant amount of time and resources in a requirements
discovery phase. Clearly there are some very interesting technical
requirements that members of this list are competent to begin to
address. But not all (or even most) of the requirements are technical.
Previous editions of the leap second follies have made convincing
cases for legal requirements, religious requirements, business
requirements, historical requirements, science requirements and many
other requirements that should form the core of any decision relating
to a change in leap second handling. The technology is the "how" of
the implementing the decision. I would think it a tautology that the
"what" of any decision regarding civil time standards should be based
on the requirements of the full range of civil time users.
A second is not an intrinsically small unit of time. For some purposes
a nanosecond is a lifetime. For other purposes, a million years is the
blink of an eye. This decision deserves the attention to detail that
our best work demands. No public decision deserves the lazy back room
politics of the intellectually dishonest leap hour proposal. It should
be removed from the table and we should roll up our sleeves to address
the issues head on.
Rob Seaman
National Optical Astronomy Observatory
--------
1) One questions whether the designers of UTC and the drafters of the
standard really intended that the Radio Telecommunications community
have ultimate authority over not just the delivery of civil time
signals worldwide, but also over the definition of the concept of civil
time itself. The ITU isn't even the same organization under which the
standard originated. And surely we have long since passed the point
where radio signals handed the baton to computer packets as the world's
primary time distribution technology. In any event, the UTC standard
assumes implicitly that Universal Time is defined to be a close
approximation of Greenwich Mean Time. In fact, the original UTC
standard stated this explicitly:
"GMT may be regarded as the general equivalent of UT."
2) UTC does not stand alone as a standard. Coordinated Universal Time
is only the public face of a whole family of Universal Time standards
and definitions (UT0, UT1, UT2) , none of which are controlled by the
ITU. When people ("users" in most of our discussions) refer to UTC,
they almost always simply call it "Universal Time". They may not know
the details (nor should we demean them because they don't) but there
are vast quantities of detailed current usage that we ignore at our
peril.
Received on Mon Jan 24 2005 - 09:14:35 PST