[time-nuts] The forbidden question

Tue Jun 4 21:51:46 UTC 2019

I appreciate your point, one that I have emphasized to my graduate students
many times over 30 years of teaching. Of course you are entirely correct.

On Tuesday, June 4, 2019, Kevin Birth <Kevin.Birth at qc.cuny.edu> wrote:

> When a clock is represented as only losing a second in billions of years
> that is a statement packaged in a rhetorical fashion to impress readers.
> Another way to think about the statement of such long-term accuracy is
> that it is a improvement in reducing uncertainty about accuracy over time,
> and that includes uncertainty in the short term at high levels of
> precision.
>
> Consider that the SI second is 9,192,631,770 transitions of cesium, but
> that when the number of cesium transitions per second was originally
> measured, there was a plus or minus of 20 transitions.  That means in
> first generation cesium clocks there was a lurking uncertainty in accuracy
> of at least plus or minus 20 not taking into account all the other factors
> that can influence a clock¹s performance.  Now if a clock¹s time was
> uncertain by just a few transitions, then that could produce a 1 second
> loss of accuracy over billions of years.
>
> So one way to look at the claim that a clock is accurate for billions of
> years (although NIST-F2 is claimed for hundreds of millions of years) is
> that it is a clock that has reduced the uncertainty in the short run,
> making it not only precise, but accurate at high levels of precision over
> short periods of time.
>
> Now that we live in a world where big data analysis (including data feeds
> on Wall St) have ns levels of precision, reducing uncertainty in accuracy
> in primary standards is highly valued.

How precise does it need to be?

>
> Or, at least that is how I understand things.

Thanks for your reply.

>
> Best,
>
> Kevin
>
>
> --
> Kevin K. Birth, Professor
> Department of Anthropology
> Queens College, City University of New York
> 65-30 Kissena Boulevard
> Flushing, NY 11367
> telephone: 718/997-5518
>
> "Tempus est mundi instabilis motus, rerumque labentium c/ursus." --Hrabanus

To which I reply:  Tunc temporis omnia consumit omnia iubeo.

> We may live longer but we may be subject to peculiar contagion and
> spiritual torpor or illiteracies of the imagination" --Wilson Harris
>
>
>
>
> On 6/4/19, 12:43 PM, "time-nuts on behalf of William H. Fite"
> <time-nuts-bounces at lists.febo.com on behalf of omniryx at gmail.com> wrote:
>
> >EXTERNAL EMAIL: please report suspicious content to the ITS Help Desk.
> >
> >
> >Warning: Potentially heretical material below
> >
> >Let me begin by saying I am neither an engineer nor a time expert. My PhD
> >is in statistics and my spouse's PhD is in theoretical computer science,
> >working on quantum computer algorithms. Neither of us claims any special
> >expertise when it comes to time and frequency measurement. I am a radio
> >amateur and I came to this group following a recommendation from John
> >Ackermann, who very kindly answered some questions for me regarding the
> >amateur radio frequency measurement test. I thoroughly enjoy the dialogue
> >here and I think that I have learned a bit about the subject though, by
> >any
> >standard of this group, I am the rankest newbie.
> >
> >My question is a serious one. I am not trolling, nor am I trying to begin
> >an argument, nor am I implying criticism of anyone or any endeavor, here
> >or
> >elsewhere.
> >
> >What useful purpose, if any, is served by the continuing evolution of
> >clocks like NIST-F2 that now achieve accuracy along the lines of one
> >second
> >per many billions of years? Are there tangible benefits to be had? I
> >consulted an astronomer friend who advised that the current generation of
> >clocks would allow a suitable space vehicle to plant a probe squarely in
> >the middle of Alpha Centauri, if rocket technology existed to do so. We
> >have many friends in the academic computer science community who say that
> >neither conventional nor quantum computers that exist at present or in the
> >projectable future require anything like this kind of accuracy.
> >
> >By no means am I questioning the value of new knowledge qua knowledge. For
> >theoreticians like the one to whom I am wedded, no justification is needed
> >beyond the words of mountaineer George Mallory: "Because it's there." I'm
> >sure that engineers and scientists in the field of time and frequency
> >measurement feel the same. From that perspective, there need be no
> >rationalization beyond the desire to do it just a little better than it
> >has
> >been done.
> >
> >Please don't lecture me about the value of science for its own sake. My
> >career has largely been built on that principle. I'd like to be informed
> >as
> >to present or anticipated applications that require such accuracy. Are we
> >developing these incredible devices just to push boundaries? Or do they
> >have some practical purpose?
> >
> >I'll appreciate thoughtful answers. Dismissive and/or snarky replies will
> >be deleted unread.
> >
> >Thanks for your help.
> >
> >
> >--
> >Homo sum humani a me nihil alienum puto.
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>
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-- 
Homo sum humani a me nihil alienum puto.