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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

#291

Post by SonOfLilit »

gpvos wrote: post #186
thfuran wrote: post #95

Earlier quoted context omitted.

Making time less accurate just for the sake of testing in production doesn't seem great.

From 2035 it's going to be less accurate in exactly the same way. I'd argue bombcar's method is more robust. I don't know of anything that actually requires UTC to be within 1 second of average rotation-based time; having it within 2 or 3 seconds is extremely unlikely to actually break anything. But we do generally want to have measured time roughly in line with Earth time in the medium to long term.

Today it is within I think +-3 hours of earth time (China being the worst offender), because of timezones and DST. If it ever gets worse than half an hour in a country, they can always change the timezone... or just, like, change businesses' opening hours and stuff.

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

#292

Post by ordu »

CryZe wrote: post #14

How is this supposed to work? The rotation of the earth is not a constant. So we either scrap UT1 ("the atomic clock") or UTC ("the calendar"). Neither sound like an actual option. The latter would imply that at some (far off) point in the future you wake up at like 10pm as UTC and UT1 are now entirely mismatched (you may as well get rid of all time zones at that point).

> The latter would imply that at some (far off) point in the future you wake up at like 10pm as UTC and UT1 are now entirely mismatched (you may as well get rid of all time zones at that point).

We (or our descendants) can try to fix Earth rotation. All is needed is a big enough rotating mass with a variable speed of rotation.

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

#293

Post by a9h74j »

gnu8 wrote: post #116
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…

It is a uniquely crummy feeling to have your work go unused like that, but you shouldn’t let it discourage you. You reached a level of mastery on this particular thing that few people have, which is evidenced by the fact that no one else in the trading community was able to reach your company’s level of confidence and they decided to wait out the leap second instead.

> no one else in the trading community was able to reach your company’s level of confidence

So his work contributed to community wisdom, and that influential community has probably had some say in cancelling leap seconds. I wouldn't call his work wasted. I would call that notably few degrees-of-separation in making an observable difference.

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

#294

Post by quickthrower2 »

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…

A bit like buying car insurance and not claiming. Still possibly worth it.

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

#295

Post by quickthrower2 »

krick wrote: post #166
techdragon wrote: post #80

Hot take… Storing anything as UTC was a mistake and we should be using TAI for all storage and computation, only transforming into more human friendly formats for display to end users. This never needed to be a problem except we decided to make it harder to use TAI than UTC and so everything got built up off the backs of legacy bios level hardware supported UTC style clock behaviour, when we should have been using TA…

I'm not sure I support your "hot take" — it is hot and requires a lot of contemplation. But that's not the point, IMO. The point is, that there ALREADY EXIST both TAI and UTC. TAI is true monotonic (whatever it means in a relativistic universe) and doesn't make any compromises. UTC abolishes monotonicity in order to keep both the length of a second and the time relationship to the orbital rotation. They both work. Fo…

Pretty sure you are saying the same thing as the post you replied to.

They are recommending TAI for storage, compute, and not against UTC for human consumption

Although the easier hack: Abolish leap seconds from UTC!

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

#298

Post by huslage »

krick wrote: post #277
varajelle wrote: post #265

Earlier quoted context omitted.

> its rotation will stay at exactly 24 hours. The earth rotate around itself in 23 hours and 56 minutes https://en.m.wikipedia.org/wiki/Sidereal_time

It rotates itself in 23 hours and 56 minutes relative to the fixed stars . It rotates itself in 24 hours relative to the Sun . It is Earth's rotation relative to the Sun what people care about in most situations, because day and night depend on that, not on the position relative to some far-away stars.

24 hours is an average over the duration of the Earth's orbit around the sun.

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

#299

Post by eternityforest »

benlivengood wrote: post #167
techdragon wrote: post #80

Hot take… Storing anything as UTC was a mistake and we should be using TAI for all storage and computation, only transforming into more human friendly formats for display to end users. This never needed to be a problem except we decided to make it harder to use TAI than UTC and so everything got built up off the backs of legacy bios level hardware supported UTC style clock behaviour, when we should have been using TA…

As spacecraft start making return trips to Earth we'll run into similar adjustment problems because TAI doesn't progress at the same rate at different altitudes and accelerations, so there'll need to be a re-sync at some point. Satellites already have a similar problem but can just use direct synchronization with Earth since it's so close. In theory spacecraft could do the same direct synchronization to Earth time, b…

Right now there are no people outside Earth's gravity well for significant time.

As long as the Earth exists and you can communicate with people there, there's no practical reason not to use an earth based reference clock.

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

#300

Post by eternityforest »

AnotherGoodName wrote: post #197
layer8 wrote: post #177

Earlier quoted context omitted.

Arguably, being able to perform calendar calculations without leap-second information (which you don’t have for the future) is more important in applications than maintaining to-the-second accuracy over calendrical timescales. What applications and date-time libraries should really do is differentiate between timestamps, calendar plus wall-clock time, and elapsed runtime. In most circumstances, only the latter would…

You don't have dst offsets for the future either. Those keep changing. That's not a blocker. The straight up truth is that we created something in between. Some parts of earth sun alignment are in the time zone abstraction layer and leap seconds are in the seconds count layer. There's no real cause for this and we should have moved to TAI to fix this blunder long ago.

You don't have DST offsets at all in UTC, which is probably how you are storing timestamps, so you can always compute a delta between timestamps if you don't have leap seconds.
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