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The leap second’s time is up: world votes to stop pausing clocks

nature.com

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Re: The leap second’s time is up: world votes to stop pausing clocks

#361

Post by layer8 »

c3534l wrote: post #358
layer8 wrote: post #316

Earlier quoted context omitted.

Mostly due to tidal friction from the moon, Earth’s rotation is slowing down in the long term. If we don’t adjust our clocks, the difference between the solar day and our clocks will slowly grow, quadratically. See this site for more details and nice graphs: https://www.ucolick.org/~sla/leapsecs/ In 1972 it was decided that the best way to compensate for this is to insert (and sometime remove) leap seconds, so that t…

Fair enough. I guess in those days, there weren't as many systems that depended on the assumption of time lurching forward one second at a time.

Few systems actually should need to depend on the clock tick matching actual elapsed seconds, and those who do depend on accurate elapsed time usually only do so short-term (while the program is executing) and don’t need to correlate that time with calendar dates and time-of-day. Most applications could very well live with an intermittently slowed-down time-of-day clock upon leap-second insertion, or a fast-forward upon leap-second removal, and use a different API when they’re interested in accurate elapsed time. But APIs have conflated those concerns, increasing the likelihood for something to grow when e.g. unix time diverges from accurate elapsed time.

I like to think that applications should be written under the assumption that the computer could be used by time-travellers, with the clock reflecting the respective changes to “local” time. That is, you would have calendar dates and wall-clock times reflecting the time travel, plus an elapsed-time clock reflecting the CPU’s subjective time. Then design your systems around that. As a consequence, they should also be immune to leap seconds and DST switches. But I guess that’s too much to ask. ;)

Re: The leap second’s time is up: world votes to stop pausing clocks

#362

Post by mr_toad »

clnq wrote: post #20

> Or we could even decouple our sense of time from the Sun entirely, to create a single world time zone in which different countries see the Sun overhead at different times of day or night. A very interesting idea, but probably much too progressive.

And measure time in powers of ten while we’re at it. None of this 24 x 60 x 60 nonsense.

Re: The leap second’s time is up: world votes to stop pausing clocks

#363

Post by qudat »

hoytech wrote: post #103

In 2015 I was working at a "fintech" company and a leap second was announced. It was scheduled for a Wednesday, unlike all others before which had happened on the weekend, when markets were closed. When the previous leap second was applied, a bunch of our Linux servers had kernel panics for some reason, so needless to say everyone was really concerned about a leap second happening during trading hours. So I was assig…

The moral of the story is if everyone is slacking then you can as well

Re: The leap second’s time is up: world votes to stop pausing clocks

#364

Post by a9h74j »

weird-eye-issue wrote: post #353
Vecr wrote: post #347

Earlier quoted context omitted.

How about this? Frame one: man beats woman at chess. Frame two: woman shoots man with automatic pistol. Not sure how deep the original really is if you think about it...

The problem is you are trying to make something "deep" when it wasn't trying to be

IIRC, Russel's thesis was something to the effect of ultimate supremecy of man over machine. I associate "Sept 1952" as the issue. The last frame suggested a certain obviousness and nonchalance in the man unplugging the computer, as if no great debate would be involved. I wonder if the article itself might now evidence too much of innocence back in that day, aside from a prediction that computers would eventually beat humans at chess. Too much innocence regarding technological imperitives and the technosphere?

Re: The leap second’s time is up: world votes to stop pausing clocks

#365

Post by jeff-davis »

The first real program I wrote was a forum in perl. But I didn't want to use "advanced" features like "use" (perl's word for importing a module). It just seemed too magical.

So, I had limited time manipulation capabilities. I tried to write all the date handling stuff by hand (with a lot of "if" statements for the special cases). I recall trying to make leap seconds work, but not sure if I actually did. It worked well enough for my purposes.

Also, no database, so I did it all with flat files. Worked better than you might expect (thanks to built-in flock()), but I wouldn't recommend it.

Re: The leap second’s time is up: world votes to stop pausing clocks

#366

Post by nullc »

jylam wrote: post #59

It seems I've got an unpopular opinion reading the comments here, but having some leap seconds from time to time ensure we are able to manage them. But "no leap second should be added for at least a century" ensures there will be a y2k reckoning every century. Seems short sighted to me, even if it is not a game-changing issue, let's be honest.

Its not a leap once a century thing, it's a rejigger the timezones by an hour every four to five thousand years. (either define new zones one hour over or redefine existing ones)

We already rejigger the time zones from time to time, so thats already handled. It's still a source of issues, sure, but it's once source instead of two.

The timezone rejiggering could also be set hundreds of years in advance... rather than the very short notice we get for leap seconds.

Re: The leap second’s time is up: world votes to stop pausing clocks

#367

Post by CydeWeys »

Vecr wrote: post #347
a9h74j wrote: post #284

Earlier quoted context omitted.

> Sometimes the best solution is not a technical solution I once came across an early 1950s Scientific American article by Bertrand Russel, IIRC. It included a cartoon. Frame one: Computer beats man at chess. Frame two: Man unplugs computer.

How about this? Frame one: man beats woman at chess. Frame two: woman shoots man with automatic pistol. Not sure how deep the original really is if you think about it...

What?! That's not comparable at all. The computer isn't murdered, it's just off. Also even if you did destroy the computer, that's not murder.

Re: The leap second’s time is up: world votes to stop pausing clocks

#368

Post by nullc »

dangero wrote: post #122

Google does "leap smearing" which seems like the best human solution to this problem: https://googleblog.blogspot.com/2011/09/time-technology-and-... standardizing leap smearing algos and constants could work -Bottom layer is atomic clock seconds -We define targeted relationship between current UTC and atomic counter that will occur on a given day and time X -Time is interpolated to drift UTC into place by the given…

Leap smearing is awful except for rough synchronization operations that don't care if you redefine a second, and even there it isn't great even if you know the exact smearing formula because you can't easily tell if the data you're getting is pre-smeared or post-smeared, or should be smeared but isn't, and then you end double smearing or inverse smearing by accident.

Re: The leap second’s time is up: world votes to stop pausing clocks

#369

Post by nullc »

euroderf wrote: post #16

Hot take: Leap seconds caused by astronomers refusing to modify their own software, instead getting the rest of the world to modify theirs. Too facile?

Nah. Its common for astronomy to use GPS time and then apply the corrections from BIPM Circular T to get UT1.

For sophisticated astronomy systems the elimination of leap seconds should simplify and reduce a source of errors. As it is, since Circular T is against UTC you need to take your local source of time and worry if leap seconds have been correctly applied (apply leap seconds to gps time or make sure haven't been fed smeared NTP time or other horrors) before you can get UT1.

Fairly casual astronomy, no-- but that isn't driving international standards, and there mechanical uncertainties dominate so you'll end up doing a 1-star correction in any case which immediately corrects the clock.

Re: The leap second’s time is up: world votes to stop pausing clocks

#370

Post by School-Cotton »

clnq wrote: post #195
magnio wrote: post #57

Earlier quoted context omitted.

How do you know whether the sun is up or down in a place when all places have the same time?

I see people bringing this question up as a counter-argument for a unified time. But how do you know whether the sun is up or down in any given place on Earth right now? You probably don't, if the place is a few thousand miles East or West from where you are. You'd have to look up its time zone. And doing that might not be that much different from looking up at what hour the solar noon is somewhere else.

You could do that, sure. Whenever I want to schedule a meeting with someone in Zurich, I could reason “15:00 UTC is about an hour before solar noon for me and — looking it up — about four hours past for him. Reasonable time for a meeting.” This would prove so useful in practice that people would rapidly start referring to times that way when talking to people from abroad: “sorry I couldn’t take your call, it was seven hours past solar noon for me; I was having dinner.” Everyone would memorize their location’s offset from UTC and use it colloquially all the time.

Oh wait, we’ve reinvented time zones!

Basically, the point of time measured in hours and minutes is to be useful to humans in daily life. And it’s useful to have a common language for things relevant to humans.

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