Re: [LEAPSECS] A consolidated approach.
That's an interesting approach getting ISO involved. I have no direct experience with that group; can you fill some of us in on the workings, or the scope of that institution? And specifically, how does ISO relate to, or compare to, ITU, or BIPM (which I assumed was in change of the system of units we use). Or the UN for that matter. As for your universal comment; that's problematic. I suspect you will find many uses of that word which are quite unrelated to astronomy; from universal studios to universal health case. If in fact a revised or new time scale still has the word universal it in, chalk it up to history. I mean, we still talk about dialing a number, even though rotary phones are long gone. We use the word on line even though there is now rarely a telephone wire involved (and don't you love, wireless on-line). Flushed with their success to demote Pluto isn't grounds for astronomers or ISO policing the world of timing and removing the word universal from any time scale that has better stability than earth. Couldn't one could equally make a case that basing a time scale on a generic undisturbed cesium atom is far more universal than the unpredictable rotation of a particular planet? In which case you should move to strip the word universal from UT1, etc. A suggestion -- call your the new time scale ISO-86400. If it includes leap seconds, then go for ISO-235960. /tvb ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] A consolidated approach.
On Dec 15, 2010, at 7:49 AM, Tom Van Baak wrote: As for your universal comment; that's problematic. I suspect you will find many uses of that word which are quite unrelated to astronomy; from universal studios to universal health case. Lots of terminology is overloaded. The ITU on the other hand is attempting to underload the historical meaning of Universal Time as an analogue to Greenwich Mean Time. It is the long and tangled history that matters, not the wordplay. Many communities - not just shabby and shameless smelly old astronomers - refer to UT as being equivalent to GMT. The ITU is acting as if it won't be ridiculously confusing (and yes - potentially dangerously so) for UTC to mean nothing whatsoever similar to UT - and for the historical sequenced of UTC to have a kink in the middle with differing rates on either side. If in fact a revised or new time scale still has the word universal it in, chalk it up to history. I mean, we still talk about dialing a number, even though rotary phones are long gone. We use the word on line even though there is now rarely a telephone wire involved (and don't you love, wireless on-line). The ITU is actually suggesting the opposite - that they serve as dictionary police to dissuade such colloquial usage. They don't want to chalk it up to history, they want to erase the blackboard. Tap-tap-tap...excuse me Ma'am, did I just overhear you say that you were going to 'dial your cellphone'? Rather, surely you meant to say that you were going to 'use the keypad to enter a phone number'? This is a serious offense! You will have to come with me down to the station. Orwellian. Couldn't one could equally make a case that basing a time scale on a generic undisturbed cesium atom is far more universal than the unpredictable rotation of a particular planet? No. And why is predictability the defining characteristic of a useful timescale, rather than the actual macroscopic phenomena (time-of-day) that is being predicted? These are two different kinds of time - interval time and earth orientation time. Universal is a term that has historically denoted the latter. It is puerile to arbitrarily shift it to the former. If wordplay really seems that important, note that they (that shadowy they) are seeking to replace International Atomic Time, a nicely descriptive phrase, with Coordinated Universal Time - a name that is even less appropriate for what has heretofore been rather shakily called atomic. Pick a different name. This was the consensus in Torino in 2003. In which case you should move to strip the word universal from UT1, etc. As neat an example of reductio ad absurdum as there is. A suggestion -- call your the new time scale ISO-86400. If it includes leap seconds, then go for ISO-235960. I support the implicit recognition here that there are (not needs to be, not should be, but are) more than one timescale. An appropriate political question (with stakeholders far beyond ITU, ISO or BIPM) is whether civil timekeeping should remain tied to one of the subset of these timescales that expresses mean solar time. It is also an interesting notion to explicitly separate the technical name of the timescale from the human-usable name. This is just the notion of an indirect pointer from computer science (or reflects activities like drug marketing, Tylenol = acetaminophen, for instance). Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] A consolidated approach.
If ISO does publish a standard, I hope they distribute it better than they did ISO 8601. In that case, they made it absurdly expensive, and then published a free summary of it on their website claiming it was the best way to write dates, but left out so many important details that anyone who relied on the summary was likely to write incorrect dates. Gerry Ashton ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] A consolidated approach.
On Mon 2010-12-13T18:52:18 +, Poul-Henning Kamp hath writ: Actually, I'm pretty sure time is entirely independent of which way you orient the Earth. It is barely a decade during which the literature and nomenclature of the astronomical community has explicitly recognized that truth. Even most astronomers have not yet assimilated the new paradigm. It will be yet a while before the distinctions percolate through the operational systems and culture. Rather than add the new (and vitally necessary) concept, the ITU-R effort seeks to discard the old concept in favor of the new one with no regard for the longstanding cultural and legal applications of the old concept. -- Steve Allen s...@ucolick.orgWGS-84 (GPS) UCO/Lick ObservatoryNatural Sciences II, Room 165Lat +36.99855 University of CaliforniaVoice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] A consolidated approach.
In message 20101213190904.ga1...@ucolick.org, Steve Allen writes: On Mon 2010-12-13T18:52:18 +, Poul-Henning Kamp hath writ: Actually, I'm pretty sure time is entirely independent of which way you orient the Earth. It is barely a decade during which the literature and nomenclature of the astronomical community has explicitly recognized that truth. It is sort of ironic that the proud disciples of Copernicus have such a hard time letting go of geo-centrism ? And what happened to boldly go ? Shouldn't we discuss what we want from our timescale in the future, rather than which 30 year old computers we will need to replace ? Poul-Henning ...Who held the papertape with the ALGOL reduction programs for the PERTH70 catalog in his hands just a few days ago :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
Re: [LEAPSECS] A consolidated approach.
Poul-Henning Kamp wrote: Actually, I'm pretty sure time is entirely independent of which way you orient the Earth. Well, Ernst Mach and Albert Einstein might be among those who quibble :-) Threads on this mailing list (and the original Navy list) have often made an implicit assumption that time is some Platonic ideal. Rather, whether a timescale is atomic or layered on Earth orientation or some other phenomena, ultimately the clock in question relies on some measurement process. Our society certainly equates time with time-of-day. My point being that this list is for discussing the requirements for civil timekeeping, not some esoteric technical timescale. This is an engineering question, not philosophy. (Irrelevant digressions about apparent timescales directed to /dev/null.) We have any number of degrees-of-freedom available for tweaking. Completely disconnecting civil time from time-of-day is not one of the possibilities. Leap seconds are a mechanism for synchronizing with time-of-day. There are other possible mechanisms. It is not the members of this list (any of us) who have demonstrated an unwillingness to consider all the actual possibilities. Shouldn't we discuss what we want from our timescale in the future, rather than which 30 year old computers we will need to replace ? Of course. We could have been discussing any number of interesting questions rather than spending 10 years fending off a badly designed proposal that is pursuing an inane hidden agenda. That said, any world-scale re-engineering project had better include requirements derived from legacy systems. Rob ___ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
