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No leap second will be introduced at the end of December 2026

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Re: No leap second will be introduced at the end of December 2026

#91

Post by Perz1val »

Vvector wrote: post #85
pdonis wrote: post #62

Earlier quoted context omitted.

> This means the atomic clock is behind the solar clock by 37 seconds? If anything, it's the other way around. A UTC day is defined as exactly 86400 SI seconds. But an actual mean solar day is a few milliseconds longer (although the difference is not constant due to irregularities in the Earth's rotation--but the average difference is expected to slowly increase over time). SI seconds are counted by atomic clocks, so…

"In other words, we want UTC noon to be within a second of mean solar noon on the prime meridian." Why? If I travel 1 mile east or west of the prime meridian, my solar noon now comes 2-3 seconds earlier/later. It's nearly impossible to have your local time match your local solar noon. For most of the population, solar noon is, on average, 30 minutes off of 12:00 noon. Plus, solar noon varies from day to day by 10-20…

Probably there are things more important than your lunch that need time to be exactly synced with sun position

Re: No leap second will be introduced at the end of December 2026

#92

Post by Xenoamorphous »

_alternator_ wrote: post #50
doctoboggan wrote: post #30

What causes the unpredictability in this? I would have guessed we have earth's rotation and orbit down to many decimals. Does geological activity, weather, or something else cause rotation speed differences that we just can't predict?

In short, yes, the weather, geology, and signicantly, human movement of water via aquifer draining and dam building, as well as glaicial and ice melts, all contribute to unpredictable changes in the earths rotational period, as well as the axis of rotation. The models for this are IIRC trigonometric polynomials of fairly low order, so even if we could model the unpredictability perfectly, truncation error would limit…

A butterfly flaps its wings in Tokyo and we lose a leap second.

Re: No leap second will be introduced at the end of December 2026

#93

Post by BurningFrog »

ortusdux wrote: post #58
t1234s wrote: post #27

They should have a global holiday to celebrate the people who maintain time/date related code in OS kernels that keeps the world from imploding.

I like the argument that we should have 12 months that are exactly 30 days long, and then merge whatever is left into a single timeless holiday.

There would be 5-6 days without time every years?

Re: No leap second will be introduced at the end of December 2026

#94

Post by hwc »

tialaramex wrote: post #70
_alternator_ wrote: post #50

Earlier quoted context omitted.

In short, yes, the weather, geology, and signicantly, human movement of water via aquifer draining and dam building, as well as glaicial and ice melts, all contribute to unpredictable changes in the earths rotational period, as well as the axis of rotation. The models for this are IIRC trigonometric polynomials of fairly low order, so even if we could model the unpredictability perfectly, truncation error would limit…

2035 is the agreed drop dead date. Everybody agreed that "Leap seconds" are a sufficiently bad idea that they should be replaced by 2035. Nobody has agreed how to fix it, and "Just turn them off" isn't technically legal. However, "What if there were Leap hours instead?" is technically legal and of course those hours would happen in the very distant future (likely after our civilisation is gone) so it's functionally i…

just move the prime meridian. the one we use for timekeeping doesn't have to aligh with longitude forever.

Re: No leap second will be introduced at the end of December 2026

#95

Post by TimTheTinker »

RugnirViking wrote: post #42
returningfory2 wrote: post #26

As one HN comment said years ago: I feel leap seconds have always lived in the wrong abstraction layer. They should live in the same abstraction layer that does leap days and daylight savings: the time zones.

god that would be awful. Can you imagine time zones being one second off from each other. Or two or three? ah yes, india is GMT+4:30:03, where europe is GMT+0:59:58

The TZDB could handle it though

Re: No leap second will be introduced at the end of December 2026

#97

Post by tialaramex »

jeffrallen wrote: post #82
tialaramex wrote: post #70

Earlier quoted context omitted.

2035 is the agreed drop dead date. Everybody agreed that "Leap seconds" are a sufficiently bad idea that they should be replaced by 2035. Nobody has agreed how to fix it, and "Just turn them off" isn't technically legal. However, "What if there were Leap hours instead?" is technically legal and of course those hours would happen in the very distant future (likely after our civilisation is gone) so it's functionally i…

Farage is such an ass, the King should make him feed donkeys or something.

"Vote Count Binface and Bin the Cunt" :D

There's a long tradition in the UK of having electoral candidates who don't expect to win but run because it's free publicity in a high profile race. "Count Binface" is a comedian who dresses up as a space alien whose outfit resembles well, having a Bin for a face. The serious political parties told Nigel to fuck off, if he wants to step down and then immediately contest the same seat they wouldn't run against him in this farce, but Binface isn't a serious politician so he is running in that by-election.

Nigel wanted to be able to do this whole thing about how the establishment is rotten and he (Wealthy public schoolboy who keeps lying to people and doesn't bother going to Parliament even though he was elected to do so) is a true man of the people and can put things right. It got him this far in life. But with the other candidate on your ballot being a space alien it's obvious which of these options is really "the establishment" and it's not the guy whose policies include "Building at least one house†" and who says he comes from a different planet...

† British political parties often insist they will build lots of housing because that's popular with voters. But, in practice they don't tend to really deliver because the various groups lobby not to actually build. So "at least one house" is a joke about this phenomenon, while conveniently also being technically possible, Binface could just build a house, that's a thing you can do.

Re: No leap second will be introduced at the end of December 2026

#98

Post by pdonis »

Vvector wrote: post #85
pdonis wrote: post #62

Earlier quoted context omitted.

> This means the atomic clock is behind the solar clock by 37 seconds? If anything, it's the other way around. A UTC day is defined as exactly 86400 SI seconds. But an actual mean solar day is a few milliseconds longer (although the difference is not constant due to irregularities in the Earth's rotation--but the average difference is expected to slowly increase over time). SI seconds are counted by atomic clocks, so…

"In other words, we want UTC noon to be within a second of mean solar noon on the prime meridian." Why? If I travel 1 mile east or west of the prime meridian, my solar noon now comes 2-3 seconds earlier/later. It's nearly impossible to have your local time match your local solar noon. For most of the population, solar noon is, on average, 30 minutes off of 12:00 noon. Plus, solar noon varies from day to day by 10-20…

> Why?

Um, because it's the prime meridian and that's how UTC is defined?

> It's nearly impossible to have your local time match your local solar noon.

Which is why I specified on the prime meridian, which is the particular local meridian that UTC is defined as corresponding to.

> solar noon varies from day to day by 10-20 seconds.

Which is why I was careful to specify mean solar noon.

I'm not quite sure what your issue is. Yes, we have time zones tied to specific meridians, and the actual sun's speed in the sky varies (which I mentioned in my post, so I'm not sure why you seem to think I'm unaware of it) so in most places local time by the clock doesn't match local time by the sun. Yes, a leap second adjustment to UTC is quite a bit smaller, taken in isolation, than the annual variation in actual solar time vs. mean solar time.

But over time, if we didn't have leap seconds, the difference would accumulate. The accumulated difference now between UTC and TAI is 37 seconds--which is almost twice the maximum variation in actual solar noon from mean solar noon that you refer to. We humans have collectively decided that we don't want that, and that it's better to do the adjustments a little at a time rather than in bigger lumps.

Re: No leap second will be introduced at the end of December 2026

#99

Post by _alternator_ »

lloeki wrote: post #76
_alternator_ wrote: post #50

Earlier quoted context omitted.

In short, yes, the weather, geology, and signicantly, human movement of water via aquifer draining and dam building, as well as glaicial and ice melts, all contribute to unpredictable changes in the earths rotational period, as well as the axis of rotation. The models for this are IIRC trigonometric polynomials of fairly low order, so even if we could model the unpredictability perfectly, truncation error would limit…

> Russia needed time to update glassnoss satellites GLONASS maybe? or really glasnost era satellites?

Glonass is correct. On mobile, thanks for the correction.

Re: No leap second will be introduced at the end of December 2026

#100

Post by soiltype »

ortusdux wrote: post #58
t1234s wrote: post #27

They should have a global holiday to celebrate the people who maintain time/date related code in OS kernels that keeps the world from imploding.

I like the argument that we should have 12 months that are exactly 30 days long, and then merge whatever is left into a single timeless holiday.

I've often dreamed of and revisited this idea. I first started thinking of it seriously when I realized I was paying the same rent in February as in January despite a significantly shorter-than-mean (30.4375) month...!

My ideal year is 12 months, each 5 weeks long, each week 6 days long. At the summer solstice, 3 intercalary days (bank holidays), at the winter solstice, 2 or 3 intercalary days depending on leap year.

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