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
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 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
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
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
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
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
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
Monsters from the id
What now, Dr. Moebius? Prepare your minds for a new scale... of physical scientific values, gentlemen.Mark Calabretta takes the lazy man's way out and appeals to facts: Here in a topology-free way is what the axis labels of my graph looklike during the said leap second insertion: UTC axis TAI axis DTAI 2005/12/31 23:59:58 2006/01/01 00:00:30 32 2005/12/31 23:59:59 2006/01/01 00:00:31 32 2005/12/31 23:59:60 2006/01/01 00:00:32 32 60.9 32.9 32 60.99 32.99 32 60.999... 32.999... 32 2006/01/01 00:00:00 2006/01/01 00:00:33 33 2006/01/01 00:00:01 2006/01/01 00:00:34 33The seconds keep step and the graph has no gaps, jumps or kinks.Now let's look at a leap hour introduced as an extra "fall back" hour: UTCTAI 2600-12-31T23:59:58 2601-01-01T00:00:31 33 2600-12-31T23:59:59 2601-01-01T00:00:32 33 2600-12-31T23:00:00 2601-01-01T00:00:33 33 2600-12-31T23:00:01 2601-01-01T00:00:34 33 (?) ... ... 2600-12-31T23:59:58 2601-01-01T01:00:31 33 (?) 2600-12-31T23:59:59 2601-01-01T01:00:32 33 (?) 2601-01-01T00:00:00 2601-01-01T01:00:33 3633I chose to introduce the leap hour on December 31 - I don't believe the proposal indicates the date for doing so. 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.)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?) Something like: GMT TAI 2600-12-31T23:59:58 2601-01-01T00:00:31 2600-12-31T23:59:59 2601-01-01T00:00:32 2600-12-31T23:00:00 2601-01-01T00:00:33 2600-12-31T23:00:01 2601-01-01T00:00:34 ... ... 2600-12-31T23:59:58 2601-01-01T01:00:31 2600-12-31T23:59:59 2601-01-01T01:00:32 2601-01-01T00:00:00 2601-01-01T01:00:33 But we're to believe that this would be implemented as an omitted "spring forward" hour - ignoring the fact that many localities don't currently have this option because they don't use DST at all - can't omit what you don't have in the first place. Well - fine, a "spring forward" event might look like: GMT TAI 2600-12-31T23:59:58 2601-01-01T00:00:31 2600-12-31T23:59:59 2601-01-01T00:00:32 2601-01-01T01:00:002601-01-01T00:00:33 2601-01-01T01:00:01 2601-01-01T00:00:34 2601-01-01T01:00:02 2601-01-01T00:00:35 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.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. (This announcement would be unnecessary in the Washington, D.C. city limits, of course.)And more to the point, since international time is a fiction, this gap/overlap in civil/business/legal/historical time would occur twice
