[time-nuts] The future of UTC

Steve Rooke sar10538 at gmail.com
Fri Jul 15 13:01:29 UTC 2011


Jose,

I couldn't agree with you more and embedded in my post was this
conflict with the need to have a precise, reproducible, standard but
that does not mean that this "standard" fits the need for wall time,
with all its wobbliness and drift. When I look at time clocks they are
divided into 24 hours, 60 minutes and 60 seconds. There is no, well a
minute could be 59 or 60 or 61 seconds in an attempt to impose atomic
time to solar time. This is like trying to impose structure on chaos.

It is a very difficult problem that seems to have no solution so
perhaps we should not try to impose a solution on it and therefore
detach the two. As for turning back the clock hundreds of years, that
is hardly the case as today's astronomers need a more accurate time
than atomic time, which could be off by significant parts of a second
compared to solar time, and they work out their correct time through
published offsets.

So what is the answer to all this, ditch the embarrassment for now and
leave it to our "buzillionth generation descendants" to sort out. What
applications do we need time correct to the femtosecond, certainly not
for most of what goes on in the world, but it is vitally important for
other applications, although it's not H:M:S that are not the case
here, it's a precise period measurement that is required.

Cheers,
Steve

On 15 July 2011 22:54, Jose Camara <camaraq1 at quantacorp.com> wrote:
> Steve:
>
>        The scientific community needs a well defined second, physically
> reproducible and stable. Something like the old meter platinum bar. In fact,
> look at meter in Wikipedia, very similar issues, with Earth as a basis for
> the reference at some point. Current definition is based on length traveled
> by light in vacuum in one second. Right there - making the second depend on
> Earth rotation, changing it daily, hourly to follow the capricious wobbly
> Earth would change the meter length just as often. Basically 'turns back the
> clock' hundreds of years in accuracy, stability of the second.
>
>        Now the second definition relates to frequency accuracy, there is no
> phase information. Nothing like a femtosecond 'ball drop' somewhere that
> would define an absolute time.
>
>        Once the second became atomic, the Earth variations and slowdown
> drift (ultimately it would show the same side to the Sun like the Moon does
> to Earth, in a few buzillion years - astro-nuts enlighten me) become an
> issue, as we don't want our buzillionth generation descendants seeing
> sunrise at 3am (although they would get off work at 2pm!). Once the Earth
> day equals the Earth year, what do we do? Let's plan ahead for the UTC at
> that point. Nice wall calendars, January First only! And it is a Holiday!
>
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Steve Rooke
> Sent: Friday, July 15, 2011 3:18 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] The future of UTC
>
> Well, instead of leap seconds which seem to be the biggest bug bear
> for everyone, keep the second as 1/86,400 of the earths current
> rotation and adjust the factor used in the calculation of atomic time
> on a regular basis. No more leap seconds just leap atomic division
> factor. Unless you can try and convince the world that all this hours,
> minutes and seconds thing will have to change and some new system for
> defining the day with the granularity of some arbitrarily chosen
> factor of atomic time (which was in line with the earth's rotation 50
> years ago or so) is worked out. The day that the second was defined in
> an atomic form has always meant that it bears little relationship to
> the idea of a second that was held before it and is used in the real
> world of wall clock time now.
>
> Yes, I'm well aware that this causes major impracticalities for
> technical and scientific users but the current system of linking
> atomic time to wall time obviously has its problems. Maybe that
> original linkage decision was a bad idea and the definition of the
> wall clock second should go back to the astronomers.
>
> Steve
>
> On 15 July 2011 21:36, cook michael <michael.cook at sfr.fr> wrote:
>> Le 15/07/2011 10:33, Poul-Henning Kamp a écrit :
>>>
>>> In message<4E1FFA88.9050400 at sfr.fr>, cook michael writes:
>>>
>>> Michael, there are a few details you overlook, and rather than
>>> repeat myself, I'll point you at an article I wrote for Queue and
>>> Communications of The ACM, trying to lay out the bits:
>>>
>>> http://queue.acm.org/detail.cfm?id=1967009
>>>
>> Thanks for your ref.  I am aware of the shortcomings of the present scheme
>> and am not particularly pro leap second. It seems to me that the right
>> questions are not being addressed and certainly the proposition for change
>> as expressed and to be voted on in 2012 is premature. The US are just
>> wanting leap seconds abolished without proposing alternative schemes
>> covering all the requirements of time signal users.    Once they have been
>> defined , recommendations can be considered.  Till then , fix the bugs.
>>
>>
>>
>>
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>
>
>
> --
> Steve Rooke - ZL3TUV & G8KVD
> The only reason for time is so that everything doesn't happen at once.
> - Einstein
>
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-- 
Steve Rooke - ZL3TUV & G8KVD
The only reason for time is so that everything doesn't happen at once.
- Einstein




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