[LEAPSECS] nails in the coffin of mean solar time
seaman at noao.edu
Thu Jun 14 17:01:36 EDT 2007
> A notable difference between these versions and previous ones is
> that the CGPM's UTC shall be interpreted by the Secretary of the
> Navy as well as NIST.
So the final determination of the policy issue (yea or nay on leap
seconds) shall be whether the US military industrial complex believes
there are more risks in continuing leap seconds (tested over 35
years) or in a boundless DUT1 (never tested, heretofore negligible
for many applications). Presumably a Y2K-like inventory of DOD
systems, embedded and otherwise, is called for. Since implicit
timekeeping requirements would be made explicit in the deferred-leap
world, all DOD systems are potentially affected.
On the other hand, one can be confident the final determination of
the actual timekeeping issue (whether civil time ultimately is
reconfirmed as a flavor of mean solar time) will be decided by the
actual requirements placed on our civilization's many
instrumentalities by the fact that we live on a rotating planet in
orbit about a star that illuminates our days.
My assertion that there are many such requirements to be revealed may
yet prove wrong - although confidence in this result would only build
over decades. But then, the implicit - and therefore completely
unsubstantiated - assertion of the "leap second die, Die, DIE!" crowd
that not a single human activity - outside of astronomy and
traditional sextant navigation - could possibly depend on mean solar
time may itself also prove wrong. That the requirements and budgets
of astronomers and TSNs are considered unworthy of any consideration
also seems unfortunate.
Note that even the opponents of "leap scheduling with a granularity
of one second" acknowledge that these embargoed leap seconds must be
released with a granularity no larger than one hour. Nobody is
recommending getting rid of leap seconds, rather merely placing them
in a "lock box" for the benefit of our grandchildren's grandchildren
several hundred years hence.
In any event, one can reject the pertinence of brain-dead computing
standards such as POSIX to either decision. One way or another
software architects will have to design library interfaces that model
the actual behavior of the physical world, and applications
programmers will no longer be able to rely on naive thinking about
National Optical Astronomy Observatory
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