351–360 of 466 posts
[1] https://tidepool.stoplight.io/docs/tidepool-api/branches/mas...
Something about this doesn't make sense. My understanding is that Ramadan can happen at any season of the year (imagine fasting all day in Greenland during the summer!) because the Islamic calendar doesn't insert intercalary months like many other "lunar" calendars do. Given that, what is the benefit of having a daylight savings time at all if it's tied to the lunar calendar? Isn't the idea of DST tied to day length?
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What makes it more logical? The wheel turns all the same no matter where you mark the beginning. In the Northern hemisphere, there's actually something nice about starting the year in the dead of winter: it feels like the year is born in the spring and then dies away the following winter, not unlike a lifetime.
March should be the 1st month then I'd think. I'm pretty sure that's how the roman calendar worked. War started in spring.
Mar 31 - Aug 31 - Jan 31
Apr 30 - Sep 30 - Feb 28/29
May 31 - Oct 31
Jun 30 - Nov 30
Jul 31 - Dec 31
That highlights a few interesting cycles you can use to calculate dates from a simple count of days from the start of the year:
153 days every 5 months
61 days every 2
31 days per month
An "early reset" occurs every second month, jumping to the next 2-month cycle after the second day 30. Another occurs after every fifth month, jumping into a new 2-month cycle halfway through the last one of the 5-month. And of course, end of the year breaks the third "5-month" cycle WAY early, just before even its first 2-month is finished.
I won't try to detail the process of generating dates from this here, but I'm sure most of us here can work it out with just a little effort. Instead, here's a couple more fun facts to consider:
If you DO start the calendar from March, counting it as month 1, September (7) through December (10) map rather nicely to their own numeric positions. That seems a pretty strong hint, to me.
And I REALLY love this one:
The Gregorian cycle consists of four centuries. The first three are 36,524 days each: 100 years x 365 days + 24 days for the leap years. The hundredth year (ending in 00) is NOT considered a leap year, EXCEPT for every FOURTH hundredth. So that's 4 centuries * 36,524 days = 146,096, plus 1 more for the leap century, for 146,097.
That number is EXACTLY divisible by 7, which means the week cycle repeats WITH the Gregorian one. Good thing! Otherwise, we'd have to wait 2800 years!
> It’s not like programming languages support representing 61-second minutes anyway This is not true. Someone already noted that Raku supports leap seconds. I think this may be partly my fault, because Perl 5's most popular datetime library, `DateTime.pm`, supports leap seconds. It's my fault because I created `DateTime.pm` and implemented its leap seconds support. In retrospect, this was almost certainly a mistake.…
What was the thought process originally? Were you just too focused on the problem?
I find that if I'm too close to the problem and too focused for [arbitrary timeframe], this is the type of thing that happens. The joy of fixing something before it's broken takes over.
I find it slightly ironic that a blog that’s educating (and entertaining) us on time and timezones does not itself mention when its blogposts were published, at least on mobile. This one appears to have been published in the summer of 2024.
Thanks! The irony is not missed on me. I think I have the dates internally in the article metadata, just didn't set up my Hugo templates to display it. TODO!
Thanks for the fun and informative blog post!
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March should be the 1st month then I'd think. I'm pretty sure that's how the roman calendar worked. War started in spring.
If you DO start in March, your days/month fall into a neat little pattern: Mar 31 - Aug 31 - Jan 31 Apr 30 - Sep 30 - Feb 28/29 May 31 - Oct 31 Jun 30 - Nov 30 Jul 31 - Dec 31 That highlights a few interesting cycles you can use to calculate dates from a simple count of days from the start of the year: 153 days every 5 months 61 days every 2 31 days per month An "early reset" occurs every second month, jumping to the…
- months are counted as 3, 4, 5, ..., 14, with 13 and 14 being January and February of the following year
- the contribution of the month to the day of the week is floor(2.6 * (m+1)) - the 2.6 comes from the 13 "extra" days (over the approximation 1 month = 4 weeks) in every 5 months.
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If the continental US can do it (and it looks like it might soon, with California voting for it) I'm not sure I buy that argument. Heck if China can survive on one timezone...
They certainly could if they had started that way, but changing it now will disadvantage at least one of the countries (Spain for example), and those countries’ politicians don’t want to risk the ire of their voters for the greater good. And DST is regulated on the EU level, so can’t be changed by individual EU members without breaking EU law, like apparently individual US states can. It’s status quo bias and loss av…
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Look at it from the other direction for a moment: say we started with universal time. The whole world used UTC. Now try suggesting timezones. The idea would look absolutely insane. It would be a non-starter discussion. On the other hand the transition from timezones to UTC has some challenges but the idea itself is very worth considering. What does this tell you?
Why would that look insane at all? It's like saying that letting everybody everywhere be able to say "I work from nine to five" is insane. Or that saying that the date changes to the next day when it's midnight is insane.
Going back to that would make things more confusing. You take it for granted that we all use the same calendar. Nobody signs your paycheck using the Chinese calendar, right? You likely agree that the US using the imperial system is silly because wouldn’t the world be in a better place if we all used metric. So why the resistance to this?
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> How do you handle the date changing in the middle of the day? It seems like you would have to do absolutely nothing? Just like you do absolutely nothing to "handle" the hour changing throughout the day. People work overnight shifts. People schedule important events close to and on either side of midnight.
"did it happen wednesday the 23rd or wednesday the 24th?"
A thousand years ago, every village had their own timekeeping and it worked. Our village is now earth. What if we just abandoned daylight-savings time and timezones and just went with GMT (or anything else) for everywhere on earth? There would be cultural effects as people in California now start work at 16:00, for example...
Everyone would create local time zones and use them. It is convenient to have the clock synchronized to the local day. Using UTC optimizes for long distances when people use local clocks much more often. How do you handle the date changing in the middle of the day? If I was on UTC, the date would change at 5pm. Is that still Wednesday or would it be Thursday? Also, it doesn't solve the problem since still need to fig…
In the Jewish and Islamic calendars, the day begins/ends at sunset, and hence the date changes at that point.
Traditionally, (Western) astronomers used the astronomical day, going back to Ptolemy, in which a new day starts at noon. Part of the reason for this was that in pre-modern times it was a lot easier to precisely determine the moment of noon than the moment of midnight. Contemporary astronomy has mostly abandoned that tradition, but it still survives in the definition of Julian dates (but not Modified Julian dates which moved the day boundary to midnight)