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    Re: The leap second is dead
    From: David Iwancio
    Date: 2022 Nov 26, 20:08 -0800


    Allowing any (meaningful) difference to exist between the times used by the Nautical Almanac and the times available via radio broadcast requires adding an extra step to the end-user's computations, which adds an opportunity for a blunder and goes against historical trends.  We've gone over 70 years without the Nautical Almanac using the phrases "sidereal time" or "right ascension," and the last big change I can think of during that time is when the publishers started front-loading a phase correction for Venus into the day pages rather than requiring separate, situational calculations for the end-user.

    Aside from adding a potential new opportunity for a blunder, I feel publishers should be careful in adding any extra steps specifically because CelNav is the only back-up navigation method generally available and, of the people who might use the Almanac operationally, there's a good chance that the person reaching for it is in an emergency situation and generally having a Very Bad Day.

    To go back to mocking Elon Musk, you absolutey should not hide your car's manual door release behind interior trim panels, no matter how simple an extra step it is to remove them, because the people looking for a manual door release are probably having a Very Bad Day.  (And can you even access a Tesla's owner's manual without power?)

    At any rate, I said "if" radio broadcasts change to New UTC because, as I understand it, the ITU still hasn't officially agreed to this.  I'd be surprised if they didn't, but it's still not official on their end.

    Personal feelings on the matter outside of CelNav below:

    Leap seconds are several years older than Mark Zuckerberg.  The systems his and others' fortunes eventually came to rely on ignored standards.  The ignorance was probably innocent on the part of developers, and standards bodies probably could have done a better job at publicizing the standard, but the solution offered is... for everybody else to change to suit them?  I feel like 30 years ago Facebook would have pushed an argument for following the year 1999 with "1900b."

    I'm also irked by someone quoted in Nature's article on the vote, where a former director of BIPM's time department basically described UTC as "the timescale of science" (my paraphrase).  Ask an astronomer how many miliseconds have elapsed since 1977 January 1.0 and they have at least four perfectly valid answers, none of which are UTC.  Ask a biologist and they probably won't know, because the question isn't relevant to their field of scientific(!) study.  UTC is fundamentally the timescale of law and commerce, and cloaking it in the mantle of "science" to give it a perceived advantage irks me on several levels.

    And most people only care specifically because UTC is the timescale used by commerce.  The human biological imperative is whether the sun is above or below the horizon, but it's easier to build a machine that predicts noon than one that predicts sunrise, and one that predicts "mean" noon has even fewer moving parts than one that predicts "apparent" noon.  Once those timekeeping machines became tied to factories and railroads, the greater public was expected to shape their lives around some particular meridian rather than simple human biology.  Time zones and twice-annual clock adjustments feel like pretty weak concessions to human biology from Our Robot Overlords in comparison.

    But we all must continue to live our lives around 12:00, and we all must adjust how we define 12:00, even though it's the 21st Century and I can downlod an app on my mobile phone and set an alarm for "sunrise."

    End of Luddite Rant

    My preference (if billionaires aren't interested in buying gyroscopes made of "freakin' laser beams") is to see the Nautical Almanac use Terrestrial Time (TT) directly.  It's already well-defined (it's what TAI is supposed to be defined by, after all) and I noticed a while back that, to the precision of the Alamanac's "Increments and Corrections" tables, delta-T can be treated as a simple chronometer error for the rest of all our lives.  I think it will still hold true in the year 2134, when an underpaid research assistant will be given the urgent task of learning all this again as... well, as the clock runs out.

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