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UTC Is Enough for Everyone, Right?

zachholman.com

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Re: UTC Is Enough for Everyone, Right?

#21

Post by holman »

netsharc wrote: post #15

> This stuff moves a lot, too: the tz database (also known as the Olson database), which is the listing of timezone rules we use as programmers to calm this chaos, gets updated many times a year. Without looking it up, I would say the last change happened when North Korea decided to sync its timezone with South Korea... or have they reverted that since Trump cancelled their summit?

I think it's one of the more recent changes.

It's actually pretty cool- all of this is discussed on the tz mailing list, so you can see how it all works yourself! https://mm.icann.org/pipermail/tz/

Re: UTC Is Enough for Everyone, Right?

#22

Post by hinkley »

blunte wrote: post #16

Sadly I didn't have enough time to read the whole article... But I wish we could all just use one time. For some, midday would be 12, and for others it might be 19, but we already all use the same dates regardless of whether February is winter for one location or summer for another.

Maybe when we are an interplanetary civilization, but then only if the balance of financial power shifts off of Earth.

We are still trying to dig ourselves out of old systems where “today” and “yesterday” are logically different and we hide the problems by assuming most users are asleep at midnight. Most new systems don’t have this problem but older ones equate “tomorrow” with “start of business the day after tomorrow”.

Re: UTC Is Enough for Everyone, Right?

#23

Post by oconnor663 »

setquk wrote: post #5

Slightly off topic but I wonder how you handle time where dilation is present. For example if a spacecraft travels to mars and there is mars local time, plus time dilation from the journey, when does a transmission start from a reference frame? Not UTC related for sure! Or is it? And then what happens if someone else goes there in a different orbital pattern and the dilation is different. and then there is the questi…

If two spacecraft start going fast enough in different directions, they can disagree about what order two different events happened in. At that point, it's not enough to give an event a single time coordinate in some reference frame; you also need to know its position in space.

Re: UTC Is Enough for Everyone, Right?

#24

Post by masklinn »

netsharc wrote: post #15

> This stuff moves a lot, too: the tz database (also known as the Olson database), which is the listing of timezone rules we use as programmers to calm this chaos, gets updated many times a year. Without looking it up, I would say the last change happened when North Korea decided to sync its timezone with South Korea... or have they reverted that since Trump cancelled their summit?

Checking 2018e, that is in fact the last change to the database, though they also updated some past timestamps:

> From 1994 through 2017 Namibia observed DST in winter, not summer.

> In 1946/7 Czechoslovakia also observed negative DST in winter.

2018d had a change to palestine's DST date (a week earlier than usual), Casey Station moving from +11 to +08 and a few other historical changes/fixes.

Re: UTC Is Enough for Everyone, Right?

#25

Post by akkartik »

"Did you hear about the clock maker who was the first to add a second hand to a clock? His first prototype was a complete failure, but he got it working the second time."

Very funny, but here's the real reason (https://www.etymonline.com/word/second):

> second (n) from Old French seconde, from Medieval Latin secunda, short for secunda pars minuta, "second diminished part," the result of the second division of the hour by sixty (the first being the "prime minute," now called the minute).

Etymonline.com is awesome. I use it several times a day.

Re: UTC Is Enough for Everyone, Right?

#26

Post by politelemon »

holman wrote: post #21
netsharc wrote: post #15

> This stuff moves a lot, too: the tz database (also known as the Olson database), which is the listing of timezone rules we use as programmers to calm this chaos, gets updated many times a year. Without looking it up, I would say the last change happened when North Korea decided to sync its timezone with South Korea... or have they reverted that since Trump cancelled their summit?

I think it's one of the more recent changes. It's actually pretty cool- all of this is discussed on the tz mailing list, so you can see how it all works yourself! https://mm.icann.org/pipermail/tz/

Thanks that's a great link. Indeed as you said I'm learning quite a lot about how it works just from this thread which started about the Western Greenland timezone!

https://mm.icann.org/pipermail/tz/2017-December/025606.html

Re: UTC Is Enough for Everyone, Right?

#27

Post by snarf21 »

blunte wrote: post #16

Sadly I didn't have enough time to read the whole article... But I wish we could all just use one time. For some, midday would be 12, and for others it might be 19, but we already all use the same dates regardless of whether February is winter for one location or summer for another.

I completely agree. It isn't like we don't deal with this already planning a flight to/from Vegas or having a call with someone on the other coast. Plus we can also get rid of the abomination that is daylight savings.

I think there is a simple plan that isn't disruptive. Simply require that all times be listed in both formats. For example, 9:00 am EDT (13:00 UTC) for all printed times on all signs, etc. moving forward from some day in the future. Eventually, we can drop the first as people adjust. (This is already how we re-number or rename highway exits)

Re: UTC Is Enough for Everyone, Right?

#28

Post by zeveb »

> Base ten is lit and doing everything in twelve feels so uncivilized …

It's actually the reverse: base twelve is more elegant than base ten[0]. The only reason we think otherwise is that we're used to using base ten.

0: ½ in base twelve is .6; ⅓ in base twelve is .4, not .333333…; ¼ is .3; 1/6 is .2, not .166667

Re: UTC Is Enough for Everyone, Right?

#29

Post by pquerna »

Love this article, but one thing it skipped on was more in-depth on Leap Seconds.

You see, UTC, is kinda like another human-made-up timezone. Humans made up some rules, and UTC is a 37 second offset from TAI / International Atomic Time:

https://en.wikipedia.org/wiki/International_Atomic_Time

Re: UTC Is Enough for Everyone, Right?

#30

Post by jetrink »

setquk wrote: post #5

Slightly off topic but I wonder how you handle time where dilation is present. For example if a spacecraft travels to mars and there is mars local time, plus time dilation from the journey, when does a transmission start from a reference frame? Not UTC related for sure! Or is it? And then what happens if someone else goes there in a different orbital pattern and the dilation is different. and then there is the questi…

This is a very old problem and not limited to spacecraft. If you sail around the world eastward, each of your days is slightly shorter than the days of your countrymen and by the time you get home, you will have experienced a full additional day-night cycle. I think the solutions would be the same: separate timekeeping standards where it makes sense, like Mars, and frequent corrections to spaceships' clocks to keep in step with a universal standard like UTC as sailing ships used to do[1].

1. https://en.wikipedia.org/wiki/Noon_Gun#Time_signalling

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