Re: Monsters from the id
Rob Seaman scripsit: > Time is a fundamental element of all that we do. Surely public > policy should not be governed by a drab and dystopian vision of > a fragmented planet scrabbling randomly to keep our disjoint > clocks aligned. I agree. But I don't agree, of course, that the TI-based version of LCT causes this to happen. > The simplest - nay, the only - way to keep our clocks synchronized > one to the other is to keep them all tied to Mother Earth. Earth is a fine mother but a lousy clock. -- Dream projects long deferredJohn Cowan <[EMAIL PROTECTED]> usually bite the wax tadpole.http://www.ccil.org/~cowan --James Lileks http://www.reutershealth.com
Re: Monsters from the id
On Sat, Jan 14, 2006 at 02:09:20AM -0700, Rob Seaman wrote: >On Jan 13, 2006, at 12:46 AM, John Cowan wrote: > In the end, it will be impossible to maintain the notion that a solar > day is 24h of 60m of 60s each: we wind up, IIRC, with the solar day > and lunar month both at about 47 current solar days. > >There's a lot of difference between what happens over a billion years >and a million years. Length of day increases only about 20s per million >years. Should we be here to care in a million years, only a 1/4 of 1/10 >of >one percent tweak to the length of the "civil second" would suffice to >allow >our Babylonian clock paradigm to continue in use. Of course, since there is a future time of equilibrium (though a long time off...), the "quadratic" nature of the accumulation of leap seconds will also stop at some point, and eventually we won't need them any more. I hope the 47 day calculation takes the solar tidal influences into effect, and that the moon has to overcome that. It makes me wonder when the maximum rate of change in length of day will come? Not that we need to plan for events that far in the future - just some fun astronomy Neal McBurnett http://bcn.boulder.co.us/~neal/ Signed and/or sealed mail encouraged. GPG/PGP Keyid: 2C9EBA60
Re: Monsters from the id
On Mon 2006/01/16 00:40:28 CDT, John Cowan wrote in a message to: LEAPSECS@ROM.USNO.NAVY.MIL >I realize the ALHP has severe problems with this, but I don't approve >of the ALHP anyhow (save perhaps tactically, as explained). Agreement! But does anyone think that the leap hour proposal is anything other than a political device? If so, please describe in detail how it could/would work. Mark Calabretta ATNF
Re: Monsters from the id
Rob Seaman scripsit: > I just continue to enjoy the fact that folks > with completely opposite points of view about civil timekeeping have > the same low opinion about leap hours :-) Feel free to adopt the acronym "ALHP". > ...and Algeria had the freedom to do so precisely because UTC existed > to function as a worldwide civil timescale that continued > uninterrupted "in the background" while the local authorities > extemporized. Presumably you would assert that TI (TAI + constant) > could serve this same purpose. Indeed. > I disagree that interval time can indefinitely serve > as a stand-in for solar time. It is when the first leap hour (or > timezone migration event) occurs that interval time fails the test. > And precisely because it is a timescale that is designed to simply > tick, tick, tick in even intervals. I agree wrt leap hours, but why wrt timezone migrations? TI ticks steadily, local time jumps about as local requirements demand; both agree on the size of the second. This will break down when timezone migrations occur too often, but then we will have to do something else altogether. > >By the way, I re-counted all the secular time zone transitions > >worldwide. According to the Olson timezone database, there have > >been 516 of them since the beginning of standard time (when that > >is, of course, varies with the country or subdivision thereof). > > I think we're using the word "secular" in different ways: Yeah, we went through this before, and I'm abusing "secular" to mean "aperiodic". Excluding DST transitions, there are 516 timezone changes in the Olson files. Some of these are really duplicates because the Olson data merges zones that have had the same history since 1970, but only if they are currently in the same country; currently separate countries are always treated separately. -- John Cowan www.ccil.org/~cowan www.reutershealth.com [EMAIL PROTECTED] All "isms" should be "wasms". --Abbie
Re: Monsters from the id
On Jan 15, 2006, at 10:40 PM, John Cowan wrote:I realize the ALHP has severe problems with this, but I don't approve of the ALHP anyhow (save perhaps tactically, as explained).Nothing to add to this. I just continue to enjoy the fact that folks with completely opposite points of view about civil timekeeping have the same low opinion about leap hours :-)Indeed. But the sensible approach would be for each State government to fail to omit the hour of the normal spring transition in the year 2700, say. In that way, AEDT would become TI+1000 and a normal-looking autumn transition would cause AEST to become TI+0900.You get points for calling it "TI" instead of "UTC".Countries without DST transitions would have to actually repeat an hour, of course, just as Algeria had to do in 1940, 1956, 1977, and 1981 (the country has repeatedly flipflopped between UTC+ and UTC+0100)and Algeria had the freedom to do so precisely because UTC existed to function as a worldwide civil timescale that continued uninterrupted "in the background" while the local authorities extemporized. Presumably you would assert that TI (TAI + constant) could serve this same purpose. That was presumably the notion of the folks in Torino. I'm delighted they recognized that UTC should not be redefined. I disagree that interval time can indefinitely serve as a stand-in for solar time. It is when the first leap hour (or timezone migration event) occurs that interval time fails the test. And precisely because it is a timescale that is designed to simply tick, tick, tick in even intervals.By the way, I re-counted all the secular time zone transitions worldwide. According to the Olson timezone database, there have been 516 of them since the beginning of standard time (when that is, of course, varies with the country or subdivision thereof).I think we're using the word "secular" in different ways: secular 3 a : occurring once in an age or a century b : existing or continuing through ages or centuries c : of or relating to a long term of indefinite durationThe ~2 ms per century lengthening of the solar (or sidereal) day is a secular trend. Overlaid on this trend are all sorts of interesting more rapid periodic and aperiodic effects. Whatever adjective one might attach to the 516 ad hoc time zone transitions - secular isn't it.Rob SeamanNOAO
Re: Monsters from the id
Mark Calabretta scripsit: > If you go through the exercise trying to tie leap hours to DST, as I > challenged, you will discover that it raises many questions that are not > addressed by the leap hour proposal. I realize the ALHP has severe problems with this, but I don't approve of the ALHP anyhow (save perhaps tactically, as explained). > If you make some plausible assumptions as to how it would operate, with > DST starting and ending at the usual times of year and leap hours > occurring on new year's eve, I believe you will find it far from simple > to do in a rigorous fashion, and that at least one of the timescales is > genuinely discontinuous. Indeed. But the sensible approach would be for each State government to fail to omit the hour of the normal spring transition in the year 2700, say. In that way, AEDT would become TI+1000 and a normal-looking autumn transition would cause AEST to become TI+0900. Countries without DST transitions would have to actually repeat an hour, of course, just as Algeria had to do in 1940, 1956, 1977, and 1981 (the country has repeatedly flipflopped between UTC+ and UTC+0100). By the way, I re-counted all the secular time zone transitions worldwide. According to the Olson timezone database, there have been 516 of them since the beginning of standard time (when that is, of course, varies with the country or subdivision thereof). -- John Cowan http://www.ccil.org/~cowan [EMAIL PROTECTED] Be yourself. Especially do not feign a working knowledge of RDF where no such knowledge exists. Neither be cynical about RELAX NG; for in the face of all aridity and disenchantment in the world of markup, James Clark is as perennial as the grass. --DeXiderata, Sean McGrath
Re: Monsters from the id
On Fri 2006/01/13 18:39:01 CDT, John Cowan wrote in a message to: LEAPSECS@ROM.USNO.NAVY.MIL >> The situation with the proposed leap hour is quite different. Given >> that AEST is defined as UTC+1000, and AEDT as UTC+1100, would someone >> care to speculate, in terms similar to the above, what will happen when >> a leap hour is inserted? > >Perhaps the two scales will be labeled O.S. and N.S., as our anglophone >antecessors did when switching from Julian to Gregorian. If you go through the exercise trying to tie leap hours to DST, as I challenged, you will discover that it raises many questions that are not addressed by the leap hour proposal. If you make some plausible assumptions as to how it would operate, with DST starting and ending at the usual times of year and leap hours occurring on new year's eve, I believe you will find it far from simple to do in a rigorous fashion, and that at least one of the timescales is genuinely discontinuous. Mark Calabretta ATNF
Re: Monsters from the id
On Jan 13, 2006, at 12:46 AM, John Cowan wrote: In the end, it will be impossible to maintain the notion that a solarday is 24h of 60m of 60s each: we wind up, IIRC, with the solar dayand lunar month both at about 47 current solar days. There's a lot of difference between what happens over a billion yearsand a million years. Length of day increases only about 20s per millionyears. Should we be here to care in a million years, only a 1/4 of 1/10 ofone percent tweak to the length of the "civil second" would suffice to allowour Babylonian clock paradigm to continue in use. Alternately, we mightdecide to add one second to just one minute out of each hour.I won't claim one of these would be the choice. There are manifoldoptions for representing time. But I do assert that our descendants - foras long as they may be regarded as human - will desire to have somecommon way to represent fractions of a day. And no matter whatrepresentation they choose, they will still face the quadraticaccumulation of leap seconds or their equivalent.Far from being a motivating factor for deprecating leap seconds, thequadratic clock lag resulting from the roughly linear tidal slowing ofthe Earth is precisely the strongest argument for preserving meansolar time as our common basis for timekeeping now and forever.Besides, it is simply a charming fact of life in the solar system thatour Moon is receding while the Earth spins down. Apollo era laserretro-reflectors show that for each second our day lengthens, theMoon's orbital radius grows by a mile or so.Time is a fundamental element of all that we do. Surely publicpolicy should not be governed by a drab and dystopian vision ofa fragmented planet scrabbling randomly to keep our disjointclocks aligned.The simplest - nay, the only - way to keep our clocks synchronizedone to the other is to keep them all tied to Mother Earth. "You think the Earth people think we're strange you think."Rob SeamanNOAO
Re: Monsters from the id
Mark Calabretta scripsit: > The situation with the proposed leap hour is quite different. Given > that AEST is defined as UTC+1000, and AEDT as UTC+1100, would someone > care to speculate, in terms similar to the above, what will happen when > a leap hour is inserted? Perhaps the two scales will be labeled O.S. and N.S., as our anglophone antecessors did when switching from Julian to Gregorian. -- John Cowan [EMAIL PROTECTED] www.reutershealth.com www.ccil.org/~cowan This great college [Trinity], of this ancient university [Cambridge], has seen some strange sights. It has seen Wordsworth drunk and Porson sober. And here am I, a better poet than Porson, and a better scholar than Wordsworth, somewhere betwixt and between. --A.E. Housman
Re: Monsters from the id
> It should be clear that the gaps and repeats are fictitious, especially > if you think of AEST and AEDT as existing beyond the times when they are > in legal use. Putting it in practical terms, suppose I have a traffic > accident at 0230 on 2006/04/02, what time will the police officer write > in his report? For most times of the year he can omit the timezone spec > because there is no legal ambiguity, but to do so for this specific hour > would be insufficient, he must specify AEDT or AEST. There are two instances of 0230 but only one 0230 EST and one 0230 EDT. So that could take care of the ambiguity, if the officer were clever. Or he could use UTC/GMT/Zulu, if the office had a military background. Or, how about this for a laugh... Suppose DST were implemented with +/- leap hours. Consider if the DST switch were made around midnight instead of 2 AM. Then the Spring DST change would jump from 22:59 to 00:00 skipping the 60 minutes labeled 23:00 to 23:59. The Fall DST would be implemented after 23:59 where and extra 60 minutes labeled 24:00 to 24:59 would be added. That takes care of your EST/EDT ambiguity... /tvb http://www.LeapHour.com
Re: Monsters from the id
On Jan 13, 2006, at 4:20 AM, Ed Davies wrote: There's nothing in this text which would stop the IERS continuing to issue leap seconds as they do now except they'd have to do it five years in advance so would, presumably, have to relax the ±0.9 seconds requirement somewhat. An excellent point! Although one fails to see the benefit in a standard that doesn't constrain behavior. So one supposes that the IERS could issue a "leap 37:43" - in either direction - immediately after this droll standard takes effect?
Re: Monsters from the id
Rob Seaman quoted: Operational rules (after UTC 21 December of the transition year) 1 Tolerance The difference of UT1 from UTC should not exceed ±1h. 2 Adjustments to UTC 2.1Adjustments to the UTC time-scale should be made as determined by the IERS to ensure that the time-scale remains within the specified tolerances. 2.2The IERS should announce the introduction of an adjustment to the UTC time-scale at least five years in advance. At the time of the announcement the IERS should provide directions regarding the details of the implementation of the adjustment. 2.3All operational rules and nomenclature prior to UTC 21 December of the transition year given above no longer apply. NOTE 1 – The broadcast of DUT1 will be discontinued. NOTE 2 – Predictions of the Earth’s rotation currently indicate that such an adjustment would not be required for thousands of years. There's nothing in this text which would stop the IERS continuing to issue leap seconds as they do now except they'd have to do it five years in advance so would, presumably, have to relax the ±0.9 seconds requirement somewhat. Ed.
Re: Monsters from the id
Rob Seaman scripsit:
> And the point I'm making is that you can't shift timezones at will to
> accomplish this without creating seams in legally realized time.
We already have seams in legally recognized time.
> Just making the dark "stay put" would result in ambiguous
> timekeeping. Daylight saving time layered on solar locked standard
> time is a different thing from attempting to use an overtly similar
> mechanism to compensate for the misappropriate substitution of
> interval time for solar time.
Stripped of the adjectives, why is it different?
> What starts out as "gradual" (also known as "ignored completely")
> will end in the same familiar quadratic rush. Nothing about your
> notion mitigates this.
In the end, it will be impossible to maintain the notion that a solar
day is 24h of 60m of 60s each: we wind up, IIRC, with the solar day
and lunar month both at about 47 current solar days.
> 1) provide a system for uniquely sequencing historical events
Haven't got that now.
> 2) allow events in distant lands to be compared for simultaneity
We have that now, but it takes a computer to keep track of all the
details in the general case.
> 3) avoid disputes over contractual obligations
That's done by specifying the legal time of a given place. If I agree
to meet you under the Waverley at noon 13 March 2020, it's all
about what the U.S. Congress says legal time in New York City is
as of that date -- which is not predictable in advance. (You will also
have a problem finding the Waverley, unless you are an old New Yorker.)
> 4) minimize the potential for political disagreements
Good luck.
> 5) satisfy religious requirements
Out of scope.
> 6) keep it dark near 00:00 and light near 12:00
Agreed.
> 7) support educational goals ("Yes Virginia, the universe actually
> makes sense.")
No problem.
> 8) allow coal miners to aspire to be amateur astronomers
Eh? I am not recommending abolishing UT1, though it seems strange to
me to measure angles in hours, minutes, and seconds instead of in
radians like a proper SI-head. ("Fourteen inches to the pound, oh Bog!")
> 9) permit the construction of sundials - public clocks with no moving
> parts
Sundials don't show legal time or even a good approximation of it much
of the time.
> 10) tie an individual's first breathe on her first day to her last
> breathe on her last day
Where's the problem here? Any timescale can do that, even the Mayan Long Count.
--
John Cowan [EMAIL PROTECTED] www.reutershealth.com www.ccil.org/~cowan
The whole of Gaul is quartered into three halves.
-- Julius Caesar
Re: Monsters from the id
On Jan 12, 2006, at 10:07 PM, John Cowan wrote:If local is the middle of the night, the practical requirements of legal time are pretty much satisfied.And the point I'm making is that you can't shift timezones at will to accomplish this without creating seams in legally realized time. Just making the dark "stay put" would result in ambiguous timekeeping. Daylight saving time layered on solar locked standard time is a different thing from attempting to use an overtly similar mechanism to compensate for the misappropriate substitution of interval time for solar time.There will be no catastrophic collapse, just a gradual local adjustment as needed.What starts out as "gradual" (also known as "ignored completely") will end in the same familiar quadratic rush. Nothing about your notion mitigates this.It may not sound like it, but I am willing to be convinced otherwise- but you'll have to do a lot better than rivaling the scant lengthof the ITU proposal. How about a detailed scenario of exactly howyou see this working for a couple of neighboring but distinct localtimezones? What is the precise mechanism that might be used? A sovereign country will notice that there is too much discrepancybetween solar time and legal time to be comfortable: perhaps kids arewaiting for school buses in the dark, as happened in the U.S. in 1974.The country will then adjust its legal time, perhaps in coordinationwith its neighbors, perhaps not.That's 54 words (counting "U.S." as two) versus 138 (not expanding acronyms) for the ITU proposal. You and PHK can do better. How about the broad outline of a complete (if informal) proposal covering all the issues that have been raised? Rather, civilian users deserve as good or better a timescale as thetechnical users (who ultimately can take care of themselves). Good for what? (This is not a rhetorical question.)Let's start a list of uses of civil timekeeping! Folks are encouraged to add to the list:1) provide a system for uniquely sequencing historical events2) allow events in distant lands to be compared for simultaneity3) avoid disputes over contractual obligations4) minimize the potential for political disagreements5) satisfy religious requirements6) keep it dark near 00:00 and light near 12:007) support educational goals ("Yes Virginia, the universe actually makes sense.")8) allow coal miners to aspire to be amateur astronomers9) permit the construction of sundials - public clocks with no moving parts10) tie an individual's first breathe on her first day to her last breathe on her last day I fear I’m afraid we’re dreadfully lost I’m afraid!Rob Seaman (for Rudolph Yaber)NOAO
Re: Monsters from the id
Rob Seaman scripsit: > I went rummaging through the ITU proposal and back as far as Torino. > Found this comment from a LEAPSECS thread on 28 July 2003: > > >>> At Torino the proponents of omitting leap seconds supposed that the > >>> governments of the world might handle this situation using leap hours > >>> introduced into civil time by occasionally omitting the annual ``spring > >>> forward'' change to jump to summer/daylight time. This is definitely the PHK/JWC proposal rather than the ALHP: "civil time" refers to local legal/business time. > >>The difference of UT1 from UTC should not exceed ±1h. This, however, clearly is the ALHP. > The point I was trying to make is that you can't simultaneously omit > the overlaps/gaps and preserve anything even vaguely resembling the > familiar relationship between our clocks and the solar day. The relationship between our clocks (legal time clocks, the only kind I am concerned with) and the solar day is very weak, as I have established over and over. If local is the middle of the night, the practical requirements of legal time are pretty much satisfied. > people everywhere in the world > would have to deal with the repercussions. That the situation will > degrade slowly over a few hundred years before collapsing > catastrophically doesn't really seem to recommend the plan. There will be no catastrophic collapse, just a gradual local adjustment as needed. > It may not sound like it, but I am willing to be convinced otherwise > - but you'll have to do a lot better than rivaling the scant length > of the ITU proposal. How about a detailed scenario of exactly how > you see this working for a couple of neighboring but distinct local > timezones? What is the precise mechanism that might be used? A sovereign country will notice that there is too much discrepancy between solar time and legal time to be comfortable: perhaps kids are waiting for school buses in the dark, as happened in the U.S. in 1974. The country will then adjust its legal time, perhaps in coordination with its neighbors, perhaps not. > The subtext of both your position and the "absurd leap hour proposal" > is that civil timekeeping is so trivial that everybody from barbers > to burghermeisters should be encouraged to make public policy - after > all, these aren't "important" scientific and technical issues. Those who want UT1 or TAI know where to get it. > Rather, civilian users deserve as good or better a timescale as the > technical users (who ultimately can take care of themselves). Good for what? (This is not a rhetorical question.) > Aliens? Us? Is this one of your Earth jokes? No. -- John Cowan [EMAIL PROTECTED] www.reutershealth.com www.ccil.org/~cowan The known is finite, the unknown infinite; intellectually we stand on an islet in the midst of an illimitable ocean of inexplicability. Our business in every generation is to reclaim a little more land, to add something to the extent and the solidity of our possessions. --Thomas Henry Huxley
Re: Monsters from the id
On Jan 12, 2006, at 12:36 AM, John Cowan wrote:No one, at least not on this list, is arguing for an alignment of theabsurd leap hour proposal (henceforth ALHP) with DST changes.I went rummaging through the ITU proposal and back as far as Torino. Found this comment from a LEAPSECS thread on 28 July 2003:> At Torino the proponents of omitting leap seconds supposed that the> governments of the world might handle this situation using leap hours> introduced into civil time by occasionally omitting the annual ``spring> forward'' change to jump to summer/daylight time.This particular quote originated with Steve Allen's excellent page: http://www.ucolick.org/~sla/leapsecs/dutc.htmlI couldn't find any explicit mention of this in the discussions at Torino, but Steve must have gotten it somewhere - and as you say, not from the list. It may be an opportune time for folks to reread the presentations from Torino: http://www.ien.it/luc/cesio/itu/ITU.shtmlFor example, I found this interesting tidbit from the Russians: "This is to inform you that to our opinion it is necessary to preserve the status-quo of the UTC time scale."Considering GLONASS is always trotted out as the only explicit example of a system that fails to handle leap seconds, this seems significant somehow.More-or-less the entire text of the proposed change to ITU-R TF.460-6 is expressed here:Operational rules(after UTC 21 December of the transition year)1 ToleranceThe difference of UT1 from UTC should not exceed ±1h.2 Adjustments to UTC2.1Adjustments to the UTC time-scale should be made as determined by the IERS to ensure that the time-scale remains within the specified tolerances.2.2The IERS should announce the introduction of an adjustment to the UTC time-scale at least five years in advance. At the time of the announcement the IERS should provide directions regarding the details of the implementation of the adjustment.2.3All operational rules and nomenclature prior to UTC 21 December of the transition year given above no longer apply.NOTE 1 – The broadcast of DUT1 will be discontinued.NOTE 2 – Predictions of the Earth’s rotation currently indicate that such an adjustment would not be required for thousands of years.Note the inaccurate and self-serving "thousands of years" that is corrected to 500 years in the draft. There isn't the slightest specification (or analysis) of how a leap hour might be implemented - just an assumption that the IERS will persist indefinitely. We're certainly aware that "all operational rules" are to be changed - but what about the nomenclature? Imagine changing an ISO or SI standard - preserving a trail of coherent nomenclature would be half the document. And then, of course, the amazing fact that the document simultaneously increases the importance of DUT1 by orders of magnitude, while discontinuing its issuance. This "proposal" is not only ill considered, it is simply - well - lazy and arrogant.We already have that repeated time sequence and gap in much of the world,and live with it. These repetitions would be no better and no worse;when a gap is present, the local sovereignty can omit the gap, but thisis not a necessary feature of the proposal.The point I was trying to make is that you can't simultaneously omit the overlaps/gaps and preserve anything even vaguely resembling the familiar relationship between our clocks and the solar day. It doesn't matter whether we continue an international civil time system or abandon it for local anarchy - people everywhere in the world would have to deal with the repercussions. That the situation will degrade slowly over a few hundred years before collapsing catastrophically doesn't really seem to recommend the plan.It may not sound like it, but I am willing to be convinced otherwise - but you'll have to do a lot better than rivaling the scant length of the ITU proposal. How about a detailed scenario of exactly how you see this working for a couple of neighboring but distinct local timezones? What is the precise mechanism that might be used?The subtext of both your position and the "absurd leap hour proposal" is that civil timekeeping is so trivial that everybody from barbers to burghermeisters should be encouraged to make public policy - after all, these aren't "important" scientific and technical issues. Rather, civilian users deserve as good or better a timescale as the technical users (who ultimately can take care of themselves). Historians already deal with the discontinuity between Julian andGregorian calendars, which was similarly conducted in a decentralizedfashion between 1582 and 1924.That there was a global mess several hundred years in the past is not a particularly good reason to generate another global mess several hundred years in the future.Aliens? Us? Is this one of your Earth jokes?Rob SeamanNOAO
Re: Monsters from the id
On Thu 2006/01/12 02:36:44 CDT, John Cowan wrote
in a message to: LEAPSECS@ROM.USNO.NAVY.MIL
>We already have that repeated time sequence and gap in much of the world,
>and live with it. These repetitions would be no better and no worse;
>when a gap is present, the local sovereignty can omit the gap, but this
>is not a necessary feature of the proposal.
At the start of daylight saving where I live the clocks are set forward
from 2am to 3am. Naively it looks like there is a gap. Likewise at the
end of daylight saving the hour from 2am to 3am appears to be repeated.
The apparent gaps and repeats are simply an artifact of what happens to
a clock display when you change it to read a different timescale.
Standard time Summer timeLegal time
--
2005/10/30 00:01:58 AEST (: ):
2005/10/30 00:01:59 AEST (2005/10/30 00:02:59 AEDT) AEST
2005/10/30 00:02:00 AEST -> 2005/10/30 00:03:00 AEDT AEST/AEDT
(2005/10/30 00:02:01 AEST) 2005/10/30 00:03:01 AEDTAEDT
(: ) 2005/10/30 00:03:02 AEDTAEDT
(: ) ::
(: ) ::
(: ) 2006/04/02 00:02:58 AEDTAEDT
(2006/04/02 00:01:59 AEST) 2006/04/02 00:02:59 AEDTAEDT
2006/04/02 00:02:00 AEST <- 2006/04/02 00:03:00 AEDT AEST/AEDT
2006/04/02 00:02:01 AEST (2006/04/02 00:03:01 AEDT) AEST
2006/04/02 00:02:02 AEST (: ):
:(: ):
It should be clear that the gaps and repeats are fictitious, especially
if you think of AEST and AEDT as existing beyond the times when they are
in legal use. Putting it in practical terms, suppose I have a traffic
accident at 0230 on 2006/04/02, what time will the police officer write
in his report? For most times of the year he can omit the timezone spec
because there is no legal ambiguity, but to do so for this specific hour
would be insufficient, he must specify AEDT or AEST.
The situation with the proposed leap hour is quite different. Given
that AEST is defined as UTC+1000, and AEDT as UTC+1100, would someone
care to speculate, in terms similar to the above, what will happen when
a leap hour is inserted?
Mark Calabretta
ATNF
Re: Monsters from the id
John Cowan wrote: [If TAI - 33 s were taken as the new basis for civil timescales, then] > It is UTC that would be eliminated as the basis for local time. It could > be maintained for such other purposes as anyone might have. Yes, the IERS could maintain it as the timescale for a timezone whose local time approximates UT1 up to a second. Michael Deckers
Re: Monsters from the id
Rob Seaman scripsit: > Folks have been tossing around the notion of aligning this with daylight > saving time - but DST in what locality? Does anyone really believe that > a leap hour would be introduced on different calendar dates worldwide? > (It seems to me that the one time it is guaranteed NOT to occur is > during a daylight saving transition.) No one, at least not on this list, is arguing for an alignment of the absurd leap hour proposal (henceforth ALHP) with DST changes. What PHK and I are arguing for is this: 1) the abandonment of UTC as the worldwide base from which local time is set in favor of TAI (minus some constant offset); and 2) the recognition of the right of local jurisdictions to alleviate any practical difficulties of this change by changing their offset from TAI from one value to another. (I speak of recognition because of course sovereign jurisdictions can already change their offsets for any reason or no reason.) This has nothing whatever to do with inserting leap hours into UTC, except in the sense that it might be tactically sensible to support the ALHP in the expectation that no such leap hour would ever be introduced. > Not satisfied with the ITU position that UTC should merely be > emasculated to correspond to TAI - 33s - Nx3600s (which, of course, > really has the effect of ensuring that TAI itself will remain a > completely irrelevant mystery to the public), some would completely > eliminate UTC from the equation (or is it that they would eliminate > TAI?) It is UTC that would be eliminated as the basis for local time. It could be maintained for such other purposes as anyone might have. > But under this interpretation we're to believe that the very notion > of international civil time is anathema (except perhaps for TAI with > some oddball persistent 33s offset and either a one hour gap or one > hour repetition every few hundred years). What this means is that > *local* civil/business/legal time contains this gap or this > repetition. I suspect we can agree that the civilians/ > businesspersons/lawyers won't care whether the issue is local or not, > all they are going to see is a repeated time sequence or a gap - and > with no possibility of appeal to standard time, because standard time > as we know it simply won't exist anymore. We already have that repeated time sequence and gap in much of the world, and live with it. These repetitions would be no better and no worse; when a gap is present, the local sovereignty can omit the gap, but this is not a necessary feature of the proposal. > And historical time? Well, historians will simply have to get with > the program. Suck it up. Perhaps loudspeakers will announce the > arrival of the leap hour (or leap timezone migration event) with the > admonition to refrain from historically significant activity for the > space of one hour. Historians already deal with the discontinuity between Julian and Gregorian calendars, which was similarly conducted in a decentralized fashion between 1582 and 1924. And that's to say nothing of Sweden, which made 1700 a non-leap year (thus using a non-Julian, non-Gregorian calendar as of March 1) and 1712 a double leap year (reverting to the Julian calendar after February 30), switching finally to the Gregorian calendar in 1753. Worst of all, Nova Scotia was settled by the French in 1605 and put on the Gregorian calendar, and then switched to Julian with the British conquest in 1710 so that the dates October 2-13 were *doubled up*, first as Gregorian, then as Julian. Eventually, it switched back to Gregorian in 1752 with the rest of the British Empire. (Grotty details at http://www.tondering.dk/claus/cal/node3.html .) -- They tried to pierce your heart John Cowan with a Morgul-knife that remains in the http://www.ccil.org/~cowan wound. If they had succeeded, you wouldhttp://www.reutershealth.com become a wraith under the domination of the Dark Lord. --Gandalf
