I keep trying to find time to generate a reply to all the points raised (yet again) during this go-around. New messages keep arriving in the mean time (a phrase that appears to be under attack). Thanks to Demetrios Matsakis for keeping us informed. Thanks to Markus Kuhn for doing a nice job of summarizing why converting to leap hours is equivalent to not bothering to attempt to keep our clocks tracking time-of-day at all. Thanks to my friend Steve Allen for continuing to fight the good fight.
There are several issues to address. If I'm going to actually send this I won't get beyond the first such. Surely others must find it remarkable how willing the precision timing community is to pursue the goal of completely eviscerating the delivery of precision time-of-day to the public? Are statements like the following really how you want to sell your product to your funding agencies?
Given that the average western citizen under 30 years already today can barely add up three items in the supermarket without resorting to their mobile phones built in calculator today, I think you can safely assume that you can do anything to the timescale 100 years from now.
Shouldn't we work to educate the public, not use their ignorance of some issue as justification for degrading service?
Poul-Henning Kamp also wrote:
As a computer nerd I can fully appreciate the problems and cost of converting existing systems to cope with larger UT1/UTC difference, but that cost would be peanuts compared to the costs of implementing leap-seconds reliably in future systems that would need it.
If you expect astronomers and other supporters of the current Universal Time system to repeatedly justify continuing to use the definition of Mean Solar Time that has persisted since 1884, perhaps you could consider doing us the favor of justifying your own statements. What exact future systems are we discussing that will both 1) require the use of Universal Time and 2) not require a definition of Universal Time that is tied to the rotating Earth? I have yet to hear of a system that has trouble handling leap seconds that wouldn't have been better off using TAI instead of UTC. I have yet to hear of a system that has trouble handling leap seconds that wasn't poorly engineered in its handling of time standards. Why should the rest of us pay for some project's bad requirements discovery, bad design and bad implementation? Imagine that the underlying time standards are, indeed, changed. Why should we have any greater expectation that the same suspect engineers wouldn't make a mess of using the new standards?
Attempting to move the entire worldwide civil time system to a non-Earth based clock is equivalent to attempting to build a clock designed to run untended for 600 years - in effect, to attempting to build a millennium clock. The alarm must be designed to ring in 599 years time. The trouble with this is not only that it is a massive problem in systems engineering. The trouble with this is that the sociology of time-keeping is working against you. How naive to suppose that anyone will be paying attention when the alarm rings!
If you want engineers to build systems that correctly incorporate handling of some phenomenon, you don't require that this phenomenon only be handled every half millennium. That is a recipe for more lazy engineering. Leap seconds are a perfectly workable mechanism. Systems that don't need time-of-day should use TAI. Systems that do need time-of-day often benefit from the 0.9s approximation to UT1 that UTC currently provides. Let's stop pretending that *both* atomic time and time-of-day are not needed. Instead, let's direct our efforts toward implementing improved systems for conveying both of these fundamental timescales to users of both precision and civil time. And most definitely, let's stop these inane and embarrassing closed door discussions among biased insiders.
It ain't your clock - it's *our* clock.
Rob Seaman National Optical Astronomy Observatory