3 ms·

https://qntm.org/abolish https://qntm.org/abolish

kemiller 9y ago
You are doing important work here.
Nullabillity 9y ago
If I'm thinking about calling someone I'll check their IM status, not look at the clock. If I'm going to a store I don't visit often I'll have to look up their opening hours on a map anyway. Whether that says it's 08-20 or 16-04 couldn't matter less. And that's before getting into the even more ridiculous stuff: > First of all, we need to straighten out some terminology. The terms "a.m." and "p.m." (ante meridiem and post meridiem) are strongly deprecated now, because they refer to the position of the Sun, not of the clock. So use 24-hour time? Somehow the rest of the world manages just fine. > So, you have to say "solar noon" to refer to the instant when the Sun is at its zenith, and "twelve hundred hours" to refer to the instant when the clock reads 12:00. Similarly "solar midnight" and "zero hundred hours". And you have to use the twenty-four hour clock, it's the only way to be unambiguous. 12:00 is just an arbitrary time anyway, and even now it might not have much to do with noon anyway, depending on where you live. Hell, look have a look at the arctic circle, where noon (or day/night) doesn't have much of a meaning anyway. > Even in the best case scenario, it is impossible to retroactively scrap time zones. The past will always exist, and the people who lived there will never adopt your new standard. Nor can all of past history be renumbered. The history of timekeeping will remain exactly as complicated as it always has been, and the zoneinfo database can never be abandoned. Do you also refuse to use epoch timestamps, because they can't represent dates before 1970? Sure, you'd need to handle zones for historical data, but that'd get progressively less relevant the further away from cutoff you get.
EvanAnderson 9y ago
That's wonderful. Thank you for sharing that.
tempestn 9y ago
Your conclusion is a thing of beauty: > If it's any consolation, all of this is extremely unlikely to happen, since it relies on an international agreement between every single nation in the world. Or on China attacking and conquering the entire world and installing China Standard Time as part of a totalitarian regime, which is slightly less unlikely but still very unlikely.
Asooka 9y ago
This has nothing to do with DST.
tzs 9y ago
That's greatly exaggerating the difficulty of deciding if it is OK to call your Uncle who is about 165° east of you in a single time zone system compared to the current multiple time zone system. In fact, the procedure is the same in both systems: 1. Look at your clock. 2. Add 11 hours to clock time. 3. Ask yourself if it would be daytime at your location when your clock says that time. 4. If yes, call your Uncle. • Under the current multiple time zone system that works because clock time is close to local time. Step #2 computes the clock time at your Uncle's location, which gets you close to the local time at his location. Daylight hours are approximately the same in his local time as in your local time, aside from the seasonal variation which you can ignore if you allow yourself a reasonable margin of error (e.g., aim for calling him a couple hours or so after sunrise rather than shooting for the crack of dawn), so you can use your local time as a proxy for his [1]. • Under a single worldwide time zone system it works because your local time is about 11 hours behind his local time. The time you get in step #3 is what the time will be on your clock (and on his clock, and on everyone else's clock) when your local time is the same as his local time is right now. So if that clock time will be a good time for you to receive a call, now is a good time to try your Uncle. Of course, you probably wouldn't actually have to do any of that. Just as in his first example with the current time zone system where he Googles "time in melbourne" rather than looking at his clock and adding 11 hours, in the single worldwide time zone you would Google "local time in melbourne". In such a world, where local time can be quite a ways off from clock time, Google would surely recognize such queries and do the right thing. Heck, it might even assume you mean local time if you just did "time in melbourne" because in the single time zone there would be no need to Google for the clock time for a particular area. I'd expect "time in melbourne" to probably give something like "The local time in Melbourne is X at world time Y". That covers everything. [1] If you really are aiming for crack of dawn calling, then you will have to take into account the seasonable variation in sunrise relative to local noon, but you have to do that in both the multiple time zone system and the single worldwide time zone system.

You are doing important work here.

If I'm thinking about calling someone I'll check their IM status, not look at the clock. If I'm going to a store I don't visit often I'll have to look up their opening hours on a map anyway. Whether that says it's 08-20 or 16-04 couldn't matter less. And that's before getting into the even more ridiculous stuff: > First of all, we need to straighten out some terminology. The terms "a.m." and "p.m." (ante meridiem and post meridiem) are strongly deprecated now, because they refer to the position of the Sun, not of the clock. So use 24-hour time? Somehow the rest of the world manages just fine. > So, you have to say "solar noon" to refer to the instant when the Sun is at its zenith, and "twelve hundred hours" to refer to the instant when the clock reads 12:00. Similarly "solar midnight" and "zero hundred hours". And you have to use the twenty-four hour clock, it's the only way to be unambiguous. 12:00 is just an arbitrary time anyway, and even now it might not have much to do with noon anyway, depending on where you live. Hell, look have a look at the arctic circle, where noon (or day/night) doesn't have much of a meaning anyway. > Even in the best case scenario, it is impossible to retroactively scrap time zones. The past will always exist, and the people who lived there will never adopt your new standard. Nor can all of past history be renumbered. The history of timekeeping will remain exactly as complicated as it always has been, and the zoneinfo database can never be abandoned. Do you also refuse to use epoch timestamps, because they can't represent dates before 1970? Sure, you'd need to handle zones for historical data, but that'd get progressively less relevant the further away from cutoff you get.

EvanAnderson 9y ago

That's wonderful. Thank you for sharing that.

tempestn 9y ago

Your conclusion is a thing of beauty: > If it's any consolation, all of this is extremely unlikely to happen, since it relies on an international agreement between every single nation in the world. Or on China attacking and conquering the entire world and installing China Standard Time as part of a totalitarian regime, which is slightly less unlikely but still very unlikely.

Asooka 9y ago

This has nothing to do with DST.

tzs 9y ago

That's greatly exaggerating the difficulty of deciding if it is OK to call your Uncle who is about 165° east of you in a single time zone system compared to the current multiple time zone system. In fact, the procedure is the same in both systems: 1. Look at your clock. 2. Add 11 hours to clock time. 3. Ask yourself if it would be daytime at your location when your clock says that time. 4. If yes, call your Uncle. • Under the current multiple time zone system that works because clock time is close to local time. Step #2 computes the clock time at your Uncle's location, which gets you close to the local time at his location. Daylight hours are approximately the same in his local time as in your local time, aside from the seasonal variation which you can ignore if you allow yourself a reasonable margin of error (e.g., aim for calling him a couple hours or so after sunrise rather than shooting for the crack of dawn), so you can use your local time as a proxy for his [1]. • Under a single worldwide time zone system it works because your local time is about 11 hours behind his local time. The time you get in step #3 is what the time will be on your clock (and on his clock, and on everyone else's clock) when your local time is the same as his local time is right now. So if that clock time will be a good time for you to receive a call, now is a good time to try your Uncle. Of course, you probably wouldn't actually have to do any of that. Just as in his first example with the current time zone system where he Googles "time in melbourne" rather than looking at his clock and adding 11 hours, in the single worldwide time zone you would Google "local time in melbourne". In such a world, where local time can be quite a ways off from clock time, Google would surely recognize such queries and do the right thing. Heck, it might even assume you mean local time if you just did "time in melbourne" because in the single time zone there would be no need to Google for the clock time for a particular area. I'd expect "time in melbourne" to probably give something like "The local time in Melbourne is X at world time Y". That covers everything. [1] If you really are aiming for crack of dawn calling, then you will have to take into account the seasonable variation in sunrise relative to local noon, but you have to do that in both the multiple time zone system and the single worldwide time zone system.