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.