On Jan 7, 2011, at 9:32 AM, Poul-Henning Kamp wrote:
> You don't get to decide if it is a fact, of if it is, if it is an
> unchangeable one:
Indeed I don't! It is fact - or not - whether I (or you) believe or not.
> That is an issue for each nation and their government.
Given modern politics it may seem that governments and their parent
corporations determine "fact", but honestly they really don't.
> See Chinas timezones as exhibit 1.
Once more from the top. System engineering is about solving problems.
Problems are understood through iterative processes. Iteration leads to an
understanding of the inherent requirements that define problems.
Problems are one thing. Solutions are distinct. Once the problem definition
and concept of operations are well in hand, potential solutions can be
entertained.
There are facts, such that we live on a planet following a roughly elliptical
trajectory ("orbiting") a star that provides illumination. The planet is spins
and wobbling. The spin is tidally coupled in interesting ways to our Moon.
Add this all up in either subtle or quite naive ways and you can determine the
synodic period, the "day", on planet Earth. It is a requirement - a
description of the problem space - that manifold human activities are loosely
or tightly coupled to the synodic day.
This is an issue of defining the particular problem to be solved.
Leap seconds, on the other hand, are one possible ingredient to solve this
problem of civil timekeeping.
My assertion of the existence and meaning of the word "day" is NOT a argument
about any particular solution. It merely "is". By all means, dispute my
statement. Tell me that modern civilization could function with a day defined
to be 15 hours of 60 minutes of 100 SI seconds. See how far you get. Rather,
any possible international standard to define a clock for civil timekeeping
must stick hellaciously close to the synodic period of the Earth.
That's what it means to be a "requirement".
The ITU (and its apologists) need to stop confusing the one-and-only one
problem we all share, with the many possible solutions.
They have painted themselves into a corner with this mindset that there is only
one possible solution (and, I guess, many problems buzzing around like
mosquitos).
Rob Seaman
National Optical Astronomy Observatory
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