[LEAPSECS] The Battle of Flodden Field

[Rob Seaman]

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