[LEAPSECS] Two clocks are better than one

[Rob Seaman]

Hi Tom,


>> ...bearing in mind that "everyone" includes the nearly seven billion people who are completely unaware that a discussion is occurring and who would be perplexed to understand that the idea here is that the clocks on their wrists, walls, computers, and bedside stands will have nothing whatsoever to do with the obvious diurnal cadence of their lives...



> Please define "nothing whatsoever" for us. I'm confused.


It would be mere happenstance that the clock on their wrist matches the Sun in the sky.  The ITU document includes no mechanism to later correct the error.  There appears to be an assumption by some here that clocks can be spun like the Wheel of Fortune to point to a random value and to run at a random rate and that the diurnal cadence (the synodic day) matters not at all.  This is patently silly.

The whole basis of the ITU position is that the clocks will be "close enough".  Close enough to what?  Why, to the actual time-of-day.  What is the actual time-of-day?  The actual time-of-day is based on the synodic day.  The synodic day is based on the sidereal day - that is, the actual rotation of the Earth relative to the "fixed" stars.  If we don't agree on the formulation of the problem, how can a consensus solution be sought?


> I agree they are unware of the discussion. Nor will they be affected by the discussion.


This is a rather smug assertion.  What about, for instance, *amateur* astronomers?  These are likely the most prevalent citizen scientists on the planet - perhaps hundreds of thousands or millions of backyard astronomers for each basement horologist.


> To within an hour or so my wristwatch (civil time) does a great job matching the sun (some sort of solar time). And give or take a few hours (excluding those in polar regions), the same is true for the other 7 billion people on the planet.


See the semi-infinite number of my prior replies to this red herring.  Periodic and static offsets are not the issue.  The issue is the (charmingly varying) synodic rate.

Note that the word I emphasized was "everyone".  There are many many stakeholders who have not been consulted regarding these issues.  You assert that they won't be affected.  PHK asserts something more like that they *cannot* be affected in any possible cosmos of the multiverse.  Snorting doesn't make it so.

The basic engineering issue (which will anger folks much more than any of my points above), is that we are attempting to solve a problem that has yet to be clearly defined.  Civil timekeeping relies on two clocks.  They are not trivially reconcilable, but leap seconds are a proof of concept that they can indeed be reconciled.

Pretending there is a single clock - of *either* type - that can be substituted is naive and potentially dangerous.  No risk analysis has been performed.  No system engineering plan drafted.  The proposal on the table is simply to "forget the whole thing".  I will continue to assert that we cannot forget the whole thing and that it will come back to bite us.  It will bite the astronomers first and cost us $$$$ to modify our software and systems and procedures.  This is evidence of deeper issues.

The ITU apologists just want to move on.  The quickest way to move on would actually be to follow system engineering best practices.  What is the problem?  What are the use cases?  What requirements can be derived?  What are the risks?  Perhaps a sensitivity analysis.  The upcoming vote will only move things into a realm where identifying reality-conforming answers to these questions is far more urgent.

Rob