[LEAPSECS] Saint Crispin's Day

Rob Seaman seaman at noao.edu
Mon Oct 25 14:27:05 EDT 2010

On Oct 25, 2010, at 8:28 AM, Poul-Henning Kamp wrote:

> In message <6F0A7636-BC9C-4617-B925-EF3849744448 at noao.edu>, Rob Seaman writes:


>> Leap seconds are a means to an end. The end won't vanish when the

>> leap seconds do.


> But didn't that end vanish a long time ago, as in "more than 100 years" ago ?

No. Diurnal rhythms are more pronounced than ever in human systems and processes. Allowing these to drift is a poor engineering choice.

> Humans used the suns position to reckon time since times before history,

> fair enough. [etc]

These discussions of apparent solar time are a red herring confusing periodic and secular effects.

Mean solar time provides a dominant peak in the power spectrum of our lives. The equation of time just smears it out a bit in the wings. Our systems should provide that the peak remain stationary.

> The suns position in the sky has nothing to do with this, that is

> in the hands of the local(-ish) politicians who legislate your

> timezone.

I'm skeptical that leaving much if any responsibility in the hands of local politicians results in a net good to humanity :-)

By all means, however, assemble materials related to your notion that timezones can provide an acceptable substitute. Wouldn't it be swell to see such an analysis as support in a coherent and complete proposal related to the cessation of leap seconds?

> that hack which handicaps everybody else.

Again - if you believe this, shouldn't a detailed analysis of how "everybody is handicapped" by leap seconds be part of a coherent and complete proposal?

> PS: You still have not answered my question: Why did you use UTC

> when you knew it was the wrong timescale for your astronomical

> applications ?

I've answered several times. Your premise is wrong. Astronomers often use universal time. UTC is currently an acceptable approximation to universal time - "GMT may be regarded as the general equivalent of UT", as designed into the standard at the beginning before the ITU-R ever existed. The johnny-come-latelies at the ITU-R would change the meaning of UTC such that it is no longer a sub-class of UT (universal time).

We wanted universal time. UTC provided universal time. UTC will no longer provide universal time.

Bottom line: there are two kinds of time, interval time and Earth orientation time. Civil time is a flavor of the latter. Pretending otherwise is other than wise. Pretending that there is only one kind of time is simply naive.

This story shall the good man teach his son.


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