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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

#321

Post by akira2501 »

svara wrote: post #138
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 that laziness is a virtue. Think of all the time that could have been saved, had you had no plans like your partners ;)

I think it's the other way around. They had a problem which previously only impacted weekends, so it was written off entirely without consideration of whether this was happening by rule or by convention. They knew it would be a concern on any other day and yet did nothing until the day it was announced.

Idle curiosities can lead to their own waste, but the kernel panic was probably worth digging into earlier.

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

#322

Post by telotortium »

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…

> I'm not sure what the moral is here, if there is one.

As the CIA director in Burn After Reading says, "I guess we learned not to do it again."

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

#323

Post by smegger001 »

kps wrote: post #18
throw0101a wrote: post #9

> How, and whether, to keep atomic time in sync with Earth's rotation is still up for debate. […] > The CGPM — which also oversees the international system of units (SI) — has proposed that no leap second should be added for at least a century, allowing UT1 and UTC to slide out of sync by about 1 minute. But it plans to consult with other international organizations and decide by 2026 on what upper limit, if any, to…

The correct answer is obvious — to stabilize the Earth's rotation — but there are a few implementation details to work out.

Freeman Dyson figured out how to do that along time ago, he was more interested in speeding up rotation to disassemble a planet but the same method can be applied to set the rotation to a given speed.

just build a planetary motor.

encircle the earth with ferromagnetic coils, then fire asteroids (similarly banded) at the earth in a series of near misses the magnetic drag steals or imparts angular momentum depending on the direction of the asteroid relative to the earth.

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

#324

Post by peter303 »

There was talk of REMOVING a second soon because the Earth's rotation had sped up a bit. Physicists havent figured out the cause of the speed up. The previous slow downs were attributed to tidal friction and global warming (expanding seas and atmosphere).

https://www.forbes.com/sites/jamiecartereurope/2022/08/03/do...

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

#325

Post by smegger001 »

layer8 wrote: post #316
c3534l wrote: post #307

I've heard of the endless disruption that leap seconds cause for years and only now have I thought to ask the question: what was so important that the entire world needed to add or subtract individual seconds from the calendar? Seems like you'd need a pretty big justification for something like that, but I only here the horror stories, not what the leap second was supposed to actually solve.

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…

>If this is changed, some decades-old systems, some of which may be critical infrastructure, may have to be substantially modified to account for leap seconds in some other way. The mention of GLONAS in the article is one such example.

GLONAS and other GPS like systems already have to deal with the temporal effects of special AND general relativity in their time keeping. Pushing leap seconds off on to the already special case system seems like a fair trade for making every other programmer and sysadmins life easier. let the extreme corner cases deal with their problems not everyone else.

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

#326

Post by macintux »

mark-r wrote: post #133
throw0101a wrote: post #102

Earlier quoted context omitted.

> If you would detonate the moon, break it up into small pieces […] Close to the plot of a recent Stephenson sci-fi novel: * https://en.wikipedia.org/wiki/Seveneves

I hated the fact that you had to get 9/10 through the book to find out how it derived its name. The number 7 appears right at the start, but it's a misdirection.

I got about halfway through before I started skimming. Interminable.

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

#327

Post by ummonk »

shadowofneptune wrote: post #261
ummonk wrote: post #175

Just use variable speed seconds.

The problem only arose when the second was changed from being 1/86400th of a solar day to being defined by atomic clocks. The old definition worked well for civil purposes but was by the 1950s impossible to accurately co-ordinate between researchers.

We have to make adjustments when coordinating anyway since local time anywhere outside sea level needs relativistic corrections to derive global time, so might as well also periodically introduce another adjustment factor based on changes in the rotation period of the earth…

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

#328

Post by Affric »

codetrotter wrote: post #287
yreg wrote: post #259

Earlier quoted context omitted.

>Sometimes the best solution is not a technical solution (“halt the markets for 15 minutes before/after”) We've had an election recently, right on the day when DST changed. On the night of counting of the votes, the clock went 2:59 AM -> 2:00 AM. To save themselves trouble the Statistics Office instructed all vote counters that under no circumstances are they to enter or update anything in any system during the repea…

The interesting thing about DST is that it's not really repeating the hour, if you include the time zone offset in your time stamp. Here, look. Using the time zone for Norway in this example, with the `date` command on macOS. First the last second before DST ended in Norway this year. TZ=Europe/Oslo date -I seconds -jf %s 1667091599 2022-10-30T02:59:59+02:00 Then the second after. TZ=Europe/Oslo date -I seconds -jf %…

Depends on implementation. Agree that epoch makes the most sense.

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

#329

Post by helsinkiandrew »

friend_and_foe wrote: post #149
jasonwatkinspdx wrote: post #53

I'm' baffled by the section about GLONASS. Russia surely has the ability to decide whether they add or remove future leap seconds?

Of course they do. But government bodies and other institutional bodies incarnated these standards organizations in order to better coordinate with one another, and decided and committed to defering to them a long time ago. Russia is a sovereign state, they can make any decision they want to, but they decided and agreed at some point to defer to this organization for a reason.

> Russia is a sovereign state, they can make any decision they want to, but they decided and agreed at some point to defer to this organization for a reason.

I think the commenter means that there isn’t a technical reason that GLONASS can’t be changed to not add leap seconds not that Russia doesn’t have to defer to an international body.

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

#330

Post by gpvos »

SonOfLilit wrote: post #291
gpvos wrote: post #186

Earlier quoted context omitted.

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.

We have summer and winter time because that turns out to be easier than changing business hours. But I was just talking about UTC really.
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