The number of time zone that a country has is a political choice, perhaps based on geography somewhat. The size of each time zone is also variable depending on the choice the government makes.
* Look at China for example, one time zone.
* India is the same with one time zone.
* Mountain Time Zone in Canada actually stretches across 4 time zones (-9, -8, -7, -6)
* The Pacific Time Zone in Canada actually stretches across 2 time zones (-8, -9)
* Newfoundland in Canada should be geographically in the -4 time zone, but it choose to do -3.5 instead. If that's the proper value, then I'd argue Maine should be in -4.5 instead of -5.
* France should be in the UTC time zone with a tiny slice in the +1 time zone. In reality it is in the +1 time zone.
* Heck, why does time zones go from UTC-12 to UTC+14? What's with the values above UTC+12?
See: https://qph.cf2.quoracdn.net/main-qimg-0eb6e2b279845c866f903...
This part wasn't a conscious decision, because the reference frame of time and orbital mechanics were discovered long after the practice of timekeeping. We may have a similar problem on a galactic scale some day.
* Friday UTC 2300 = local time 4pm PST - This is Friday
* Saturday UTC 0100 = local time 6pm PST - Is this Saturday?
* Saturday UTC 2300 = local time 4pm PST next day - This is still Saturday?
Most servers run on UTC under the hood, and a lot of big organizations have experience already in terms of doing all timekeeping calculations in UTC. It may seem weird, but works pretty well in the long run -- and not having to deal with corner cases like DST or geographical ambiguities around time is extremely valuable.
Have you ever thought about what it's like to live near the edge of a timezone? In a city where half the city uses one time and half uses the other?
China is fine, because the day doesn't change during daylight.
Yeah, computers should use UTC. It's easy for them to convert to/from local time for the user. This is what computers are good at.
With one hour time zones:
* If someone is 3 time zones ahead, they're 3 hours ahead
* There are 24 time zones and 360 degrees neatly divides by 24
* 2 hours between time zones means that within a time zone, the sun rises on one side at 8 am and on the other side at 10 am.
I was explaining why 1 hour as the standard makes sense instead of 30 minutes or 2 hours. The :45 time zones would still be an issue for 30 minute intervals and :30 and :45 are still an issue for 2 hour intervals
But now we have computers to do all the bookkeeping. So if we wanted, we could not only return to the previous approach, but take it further to infinite time zones. Your noon is whenever the sun is overhead for you. Our calendars always include locations for events, so the time difference is compensated for. Google Maps knows that if you're traveling east or west a significant distance to make it to an event, it needs to adjust the time. Etc, etc.
Uh oh. I'm starting to think this is a good idea...
...the need to synchronize global tasks means that either you have easily-offset local times, or you just use UTC everywhere and keep it in your head when local wake / sleep is and refuse synchronized tasks outside those times.
I should note that I'm not seriously proposing it. My point is more to get people thinking. Our current hodgepodge approach is extremely historically contingent. I personally believe that there's no good solution to this, just different bad ones.
But there are half-hour aligned time-zones. Newfoundland is -3.5. It's currently 11:20 am here in Toronto and 12:50 pm in St. John's. Then there's the Chatham Islands of New Zealand with a quarter hour offset at UTC +12:45.
There are also regions where two bordering time zones change by more than 1 hour. At the Pakistani-Chinese border you gain or lose three hours.
But it would definitely screw up cultural references, e.g.: a "5pm tea" then can only be understood with a broader cultural context: "UK, 5pm is late in the 2nd half of the working day for them".
The sun rises and sets at different times according to both latitude and longitude. Timezones only handle longitudinal daylight adjustments. We already deal with plenty of incongruity around daylight.
Why not embrace the variability and let go of the idea that we can predict daylight based on the hour alone? Let people localize the time to discover where the sun is.
It does require a different way of thinking about time zones. It sounds complicated because it's unfamiliar, but if we ever make the transition, the system would be simpler, less ambiguous, and easier to reason about.
Your watch hands read '20230710T142847Z', don't they?
https://en.wikipedia.org/wiki/ISO_8601
One thing for which I would advocate is removing zero based numbering from hours and minutes. Clocks reading 12:15 for 00:15 is tremendously confusing. Most human oriented counting systems are not zero indexed. One indexed series align cardinal and ordinal numbering which reflects the passage of time rather than each hour being nominally disconnected from a sequence.
Apart from this being very funny and an interesting idea I have a question: how do you deal with leap years? Many important dates throughout the year (e.g. holidays, birthdays, business quarters etc.) are bound to specific days of months, do you just have to remember that all such days after February are one off sometimes in an ordinal date system?
Leap years: A sidereal year adjustment may occur on any day, there is not a requirement for it to occur on a specific day. Leap years merely have an additional day identifier in the series before returning to 001.
Anniversary events: Again, there is no requirement that the memorialization of a person or event occur on a specific month and day. Many occurrences such as Mardi Gras and Eid using a lunar calendar or the USA's Thanksgiving using the day of week.
If one wishes to commemorate an annual event at the same orbital position as when it occurred, then ordinal dates are more effective since the Gregorian calendar's fourth-year 02/29 throws off any anniversary after the first 1/6th of the year.
NB: ISO 8601 "leap week" instances occur at a different rate than leap years (a more parallel construction would be "leap week" and "leap day"). "[The] 53 week years occur on all years that have Thursday as the 1st of January and on leap years that start on Wednesday the 1st."
https://en.wikipedia.org/wiki/Leap_year
https://en.wikipedia.org/wiki/ISO_week_date
A higher order number than ordinal and cardinal is ratio. We can also express the current day as how far through the year we are. Since today is 192, it represents 52% of a year, the ratio of current day to days in the current year. Below is an example in bash.
$ date '+%j'
192
$ echo "scale=2; $(date '+%j') / $(date '+%j' -d $(date '+%Y')'-12-31')" | bc
.52Because it's a useful heuristic in knowing whether someone will be at work or not without having to localize every time.
having everyone roughly align their work day to 9am-5pm in their local time works a lot better than asking every single person in my company for their working hours in UTC.
the current solution is to set an explicit expectation that people work 9-5ish in their local offset.
is your proposal to do the same thing, but the expectation is that people work noon-4 to noon+4, or something like that? I don't see any major advantages to that, but I do see one major disadvantage: solar noon occurs at a different time every day. of all the arbitrary markers to align schedules with, this seems like a pretty bad one.
Yes. Rather than using solar noon at one day, we can look up an average solar noon time. It should give a better idea how people would plan their day. I understand that schedules will be different at different locations, but then 9 to 5 also has that much variation from location to location.
Just count the number of seconds since the GPS epoch in a galaxy-centered inertial frame. This post was made at 1,373,034,914.
I don't see anything referencing any planets?
"the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom taken as an average over 11 samples distributed throughout the earth in order to approximate the earth's inertial frame"
Seconds as used in Coordinated Universal Time are in fact defined based on planets, and earth specifically - because they use earth's inertial frame.
In principle this frequency can be measured in any inertial frame. Seconds are not defined on Earth specifically.
Timezones are still a social construct, and decision made. Mainland China is wider than contiguous US, and yet it runs on single TZ.
You still would have to figure out when people in SF wake up!
> You still would have to figure out when people in SF wake up!
Exactly! It is argument against multiple TZs not for it.
Except without timezones, you just have to remember that SF is 3-ish hours off so people wake up at 11am. If you just had timezones, you wouldn't have to keep this in your head!
With single TZ: - I need to learn when people at different location work.
With multiple, perfect TZs: - I still need to learn when people at different location work, and additionally I need to translate (or add TZ to) every clock time when communicating with those people.
Learning when people work is similar amount of work in both cases. You always have to keep at least time offsets for every city or even office. If you have multiple TZs you need to keep them and their offsets in your head.
That's not true — I can roughly assume that everyone is at work by 9am their time. I just need to know their timezone. If I didn't have a timezone, I'd have to memorize the approximate offset of every city in the US.
I really see no benefit.
TL;DR:
People won't wake up at local midnight because the clock says 07:00.
People won't wake up at local sunrise no matter what the clock says.
People will wake up when the people they coordinate with wake up.
If they can't change their clocks to reflect that, the hours they keep will be very unpredictable to outsiders.
I'm not suggesting anything. I'm just informing that different countries make different decisions on their TZ arrangement based on their priorities, and the arrangement that US has currently is not just some inevitably from geography.
That's because a vast majority of the country (and certainly all the politically empowered citizens) live in a much smaller span for which the single timezone is pretty accurate. It works in China by not caring about people to the West.
https://www.npr.org/sections/parallels/2013/11/30/244995264/...
> So on Oct. 23, 1940, Hitler took a train to the Spanish border to woo Spain's Fascist dictator, Francisco Franco.
> But Spain was in ruins from its own Civil War in the late 1930s, and Franco didn't have much to offer. He stayed neutral, but switched Spain's clocks ahead one hour, to be in line with Nazi Germany.
> Ever since, even though Spain is geographically in line with Britain, Portugal and Morocco — its clocks are on the same time zone as countries as far east as Poland and Hungary.
And the country/politicians are thinking about going back to UTC+0 due to all the problems UTC+1 poses due to geography.
Western Europe is not under a single timezone, though: the UK, Ireland, and Portugal are not on CET/CEST.
So what I mean is that, because integers are easy to work with, and we've arbitrarily settled on 24 hours in a day, and given time zones exist, the number of them in the lower 48 US states (4 plus Arizona's situation) is pretty far from wild. China's decision is much more of a stretch.
Hardly cheating. They are part of the United States.
Puerto Rico is as close to a state as it's possible to be without actually being a state.