Re: two world clocks AND Time after Time
In message [EMAIL PROTECTED], Clive D.W. Feather writes: Poul-Henning Kamp said: [That is, if the equinox was actually on March 9th, would anyone outside the astronomical community notice?] I doubt it. I'm not so certain about the summer and winter solstice however. here in the nordic countries were're quite emotionally attached to those. Hmm, that's because you actually get midnight sun and midday night (or approximations like the White Nights). That is probably how a foreigner would say it. We would tend to say it's because it's so bloddy dark all winter :-) But given that these dates move a day or two each year anyway because of leap year effects, you wouldn't notice the drift without being told. More superstition is attached to those, so people might not take it (as) lightly. And talking about superstition... The NeoPagans will demand that we rotate Stone Henge to match. The UFOlogist will insist that we turn the Great Pyramid accordingly. And just wait until the astrologers find out... Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
Re: two world clocks AND Time after Time
On Tue 2005-01-25T09:57:46 +, Clive D.W. Feather hath writ: I think you're out by a factor of 10. Would the Man On The Clapham Omnibus be able to identify the solstice or equinox to within 14 days? Other than knowing the conventional dates? [That is, if the equinox was actually on March 9th, would anyone outside the astronomical community notice?] The answer is in Duncan Steel's book Marking Time http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471298271.html The answer is yes, and it is evident in the orientation of churches in England built before and after the English calendar reform in 1752. Churches were built oriented to sunrise on their saint's day. In 1752 the calendar shifted, and sunrise shifted. Additions made to pre-reform churches were oriented to sunrise on the new saint's day. The result was crooked churches. Steel counts 81 such churches within Oxfordshire alone. -- Steve Allen UCO/Lick Observatory Santa Cruz, CA 95064 [EMAIL PROTECTED] Voice: +1 831 459 3046 http://www.ucolick.org/~sla PGP: 1024/E46978C5 F6 78 D1 10 62 94 8F 2E49 89 0E FE 26 B4 14 93
Re: two world clocks AND Time after Time
In message [EMAIL PROTECTED], Tom Van Baak writes: Another observation is that our local newspaper always prints Sun and Moon rise and set times. But not time of noon. Why is this? Maybe it's just our paper (noon implies sun and we don't see much of it here in Seattle). Why is the instant of sunrise or sunset of popular value while the high point of noon isn't. What does this suggest about the risk of allowing noon to wander an hour over the span of 1000 years? Several countries have codified sunrise and sunset as when traffic needs to light up. In Denmark while cars and motorbikes are lit up at all times, bicycles and horses must be lit up from sunset to sunrise. There are similar rules for vessels on water I belive. Month is entirely conventional in its meaning. Year is entirely conventional in its meaning. So soon day will be entirely conventional in its meaning. Can you explain this more? I can see how Month would be conventional, or even entirely conventional but are year and day also such extreme cases? The Year represents when the constellations repeat their performance, but the precision of this is wrecked by the leap-years, so it is only conventional these days. It seems to me the popular understanding of a year is accurate to +/-1 day. And the popular understanding of noon is accurate to +/- 1 hour or two. Does that make them entirely conventional? Seen from an astronomical point of view: yes, you can't point your telescope with it. The trick will be to educate the general public that 12:00 means slightly less about where the sun is in longitude than the Gregorian Sure, but it seems to me - regardless of the timezone, regardless of daylight saving time, regardless of the season, regardless of latitude, to the general public 12:00 means lunchtime (or their VCR got unplugged). The sun doesn't have much say about it. Fully agreed. I would even venture to claim that a lot of todays teenagers are only mildly aware of the noon -- more light outside connection :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
Re: two world clocks AND Time after Time
On Mon 2005-01-24T00:50:10 -0800, Tom Van Baak hath writ: Isn't knowing when noon is already a specialist operation? I mean, most people could tell you when noon is to within an hour or two or three, but finer than that requires a far amount of daily mental calculation, no? Noon has long required a calendar, an almanac, a longitude, and the ability to perform addition and subtraction. This has long been something that could be presumed within the abilities of any locality big enough to call itself a town. The tasks of business, payroll, and banking demand that much. Sunrise and sunset have required haversines. That's why the newspapers publish them. Trigonometry was not required for simple civil life. -- Steve Allen UCO/Lick Observatory Santa Cruz, CA 95064 [EMAIL PROTECTED] Voice: +1 831 459 3046 http://www.ucolick.org/~sla PGP: 1024/E46978C5 F6 78 D1 10 62 94 8F 2E49 89 0E FE 26 B4 14 93
Re: two world clocks AND Time after Time
In message [EMAIL PROTECTED], Steve Allen writes: On Mon 2005-01-24T00:50:10 -0800, Tom Van Baak hath writ: Isn't knowing when noon is already a specialist operation? I mean, most people could tell you when noon is to within an hour or two or three, but finer than that requires a far amount of daily mental calculation, no? Noon has long required a calendar, an almanac, a longitude, and the ability to perform addition and subtraction. You forget a lawyer or at least a copy of the relevant laws in your area, because surely you're not assuming that my watch runs on UTC ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
Re: two world clocks AND Time after Time
Steve Allen scripsit: What we are being told by the Time Lords is that, starting from a date in the near future, knowing when noon is will also be a specialist operation. Already true. For many months of the year, solar noon is closer to 1 PM, or even 1:30 PM, in a great many countries, and how many people actually realize *that*? -- Winter: MIT, John Cowan Keio, INRIA,[EMAIL PROTECTED] Issue lots of Drafts. http://www.ccil.org/~cowan So much more to understand! http://www.reutershealth.com Might simplicity return?(A tanka, or extended haiku)
Re: two world clocks AND Time after Time
On Thu 2005-01-20T14:59:18 -0700, Rob Seaman hath writ: Leap seconds are a perfectly workable mechanism. Systems that don't need time-of-day should use TAI. Systems that do need time-of-day often benefit from the 0.9s approximation to UT1 that UTC currently provides. Let's stop pretending that *both* atomic time and time-of-day are not needed. Instead, let's direct our efforts toward implementing improved systems for conveying both of these fundamental timescales to users of both precision and civil time. On Sat 2005-01-22T20:43:51 -0500, Daniel R. Tobias hath writ: Now, if a time standard is to be defined based solely on constant SI seconds, with no reference to astronomy, then why even include all the irregularities of the Gregorian Calendar, with its leap year schedule designed to keep in sync with the Earth's revolutions? It really makes no sense that TAI includes days, years, and so on at all, and this will seem particularly senseless when the current date by TAI is a day or more removed from Earth-rotational time, as will happen in a few millennia. What is really needed is two different time standards: a fixed- interval standard consisting solely of a count of SI seconds since an epoch (no need for minutes, hours, days, months, and years), and a civil-time standard that attempts, as best as is practical, to track the (slightly uneven) motions of the Earth. Of course there are other units of time in civil history which have been converted from actual representations into conventional ones. Sailors have no qualms about calling out the next high tide in terms of local civil time (now practically based on UTC). They all know that the times shift by around an hour every day. The month lost its connection with the moon early in the Roman era. Everybody knows, and in general nobody cares, that the moon is not new at the beginning of a month in the Gregorian calendar. The Gregorian year is pretty good, but three millenia hence the vernal equinox will have drifted discernably from the original intent. In general nobody cares about the date of Easter that much, and (as seen in Duncan Steel's book) even some of the best astronomers have not understood the distinction between the tropical year (as popularly defined by Newcomb) and the Vernal Equinox Year that Pope Gregory's calendar actually aimed to match. Above Rob Seaman and Danial Tobias have echoed some of the issues discussed by Essen himself in his autobiographical work Time for Reflection which his son-in-law has reproduced at http://www.btinternet.com/~time.lord/ In particular, this footnote http://www.btinternet.com/~time.lord/TheAtomicClock.htm#_msocom_1 (and the entire chapter containing it) reveals that the tension between the physicists and the astronomers (notably Stoyko, who has largely been written out of history) was great enough that there almost became two SI units for time, one being the second based on the day, and one being the Essen based on the cesium resonance. But Essen claims for himself (in both this autobiography and in Metrologia http://www.bipm.org/metrologia/ViewArticle.jsp?VOLUME=4PAGE=161-165 ) the credit for recognizing that the existing systems of time distribution (and now presumably extended to time computation) basically cannot be expected to tolerate the existence of two kinds of time. I don't think this is really true anymore, but it is admittedly costly. It was the astronomers who first made the mistake of counting a truly uniform time scale using the calendrical/sexagesimal notation originally based on earth rotations (and now concisely communicated using ISO 8601). It was the physicists who pushed to continue the practice. Knowing the tides is a specialist operation, and has always been. Knowing the phase of the moon is a specialist operation, and has been in western culture for over two millenia. What we are being told by the Time Lords is that, starting from a date in the near future, knowing when noon is will also be a specialist operation. Month is entirely conventional in its meaning. Year is entirely conventional in its meaning. So soon day will be entirely conventional in its meaning. All of them become predictable, albeit upon examination silly, extensions of things which originally meant something else. The priesthood of astronomy has become irrelevant to the general populace, and the priesthood of the physicists has taken precedence. The trick will be to educate the general public that 12:00 means slightly less about where the sun is in longitude than the Gregorian calendar date means about where the sun is in latitude. Both of these schemes fail, it's just that atomic time fails by a full hour within 1000 or so years whereas the Gregorian calendar fails by a full day only after another 2000 or so years. I really like sundials, mean solar time, and the analemma. I think it is disingenuous to use the methods we see being used by the atomic clock keepers to
