[LEAPSECS] leapseconds on trains

Rob Seaman seaman at noao.edu
Thu Nov 17 13:07:32 EST 2011

On Nov 17, 2011, at 10:41 AM, Poul-Henning Kamp wrote:

> In message <3B099BA0-B740-4D80-998C-9DBC7D4AC3DB at noao.edu>, Rob Seaman writes:


>> Real-world issues will occur whether or not they are aware of the issue and

>> whether or not they regard it as important.


> I'm sorry to say it so bluntly, but you sound downright silly now.

And an actual universe exists whether or not I sound silly. (I also presume you are just being polite and don't actually mind being blunt :-)

What, however, is silly? An implicit assertion for the past dozen years has been that nobody except astronomers (and similarly silly communities) can possibly care what direction the Earth is pointing. Why is an unexamined, incurious assertion "non-silly"?

Trains, plains, ships, trucks, industrial logistics, economic forces of all descriptions - all have been implemented in a world in which clocks provide mean solar time. Mean solar time keeps them synchronized one with the other, but also with diverse natural rhythms. That you can't imagine that any system or procedure in the modern world might care about Earth orientation doesn't make it so. I'm flabbergasted that the blatant evidence of damage that will be caused to astronomical and aerospace infrastructure is rejected.

But that aside, it is also simply the case that this vast panoply of systems is "coordinated" *on top of* mean solar time. As you guys keep pointing out, sometimes systems drift away because they ignore leap seconds or for other reasons. When corrections are applied, it does not *currently* matter where the corrections originate, precisely because mean solar time has a coherent physical meaning. If UTC is redefined, not only will the time signals have to adhere to an artificial standard, but also the corrective measures. Nobody knows if in every instance a coherent artificial model of timekeeping will be applied in the future - because nobody has looked. I am skeptical. You are curiously not. Who is silly?

Leap seconds are a sideshow. The main event is the redefinition of UTC to no longer be Universal Time.


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