10 ms·
No leap second will be introduced at the end of June 2026
- shablulman 8mo ago[flagged]
- wlkr 8mo agoInteresting! There's a lot I don't know about this, but I know a little more now. I'll admit, I naively thought this would be more regular than it appears to be [0]. [0]: https://en.wikipedia.org/wiki/Leap_second https://en.wikipedia.org/wiki/Leap_second
- butILoveLife 8mo agoThey teach us Scientific Realism in school, but reality is that we are really using Instrumentalism. That said, no one wants to admit it, so contemporary science follows Falsification, where we find ways to not actually make claims about reality. (Which as an Instrumentalist/pragmatist, I love Karl Popper, its just not metaphysical truth. And that would break Popper's heart)
- voxl 8mo agoA distinction without a difference. The only way we can interact with the world is via senses, via instruments, via measurement. We can rehash solipsism, but seeing as how that is an immediate dead end we all agree there is a physical reality. If there is in fact a reality, then we are measuring something real.
- butILoveLife 8mo ago>we are measuring something real. I think it matters. No the planets are not doing circles around the sun. Circles don't actually exist, they are doing elipses. Also 'real' has quite a few meanings. If I ask the question 'Are you closer to a keyboard or the gym?' does that question exist? This kind of stuff does end up mattering. It becomes much more noticeable in psychology (and biology). If you read Freud, Adler, or Jung, you will say 'Oh extrovert! I've seen that before!' But then you realize its vague and almost always true. Its like a horoscope. So if we think there is a truth to reality, we look for perfect relations. If we think its impossible for humans to figure out, we look for best fits.
- riskassessment 8mo ago> They teach us Scientific Realism in school. I'd argue the opposite is true for anyone who has studied statistics which is largely built on Instrumentalism (think George Box: 'All models are wrong, but some are useful') and Popperian falsification (Null Hypothesis testing). We are absolutely taught to treat models as predictive tools rather than metaphysical truths.
- butILoveLife 8mo agoStatistics is even presented like metaphysical truth. Or at least my experience in engineering school. And taking fluid dynamics, we used renyolds number, which is a made up ratio that helps for decision making... Its not like when we answered questions, we could answer the grey area we are discussing. If I had to guess, I think its due to western civilization being built of Platonism (and even Aristotle was infected). Our science and morality is later built by platonic realism. Only in the last 100-ish years are we starting to get over it.
- exac 8mo agoNo they do not teach Scientific Realism in schools. We're taught the scientific method and then build upon that. I can see how someone could misunderstand or forget what they're taught though.
- butILoveLife 8mo agoK12 teachers arent educated enough to realize the words they use imply scientific realism.
- anotherpaulg 8mo agoThe Earth is generally expected to spin more slowly over time, due to tidal friction. But it has been spinning faster and faster since the 1960s. As shown in the figure in the wikipedia article [0]. I have read numerous explanations, but haven't found a really authoritative discussion. [0] https://en.wikipedia.org/wiki/Leap_second#Rationale https://en.wikipedia.org/wiki/Leap_second#Rationale
- pinkmuffinere 8mo agoWow that's really interesting. A great quote form the article: > In 2021, it was reported that Earth was spinning faster in 2020 and experienced the 28 shortest days since 1960, each of which lasted less than 86399.999 seconds.[24] This caused engineers worldwide to discuss a negative leap second and other possible timekeeping measures, some of which could eliminate leap seconds.[25] The shortest day ever recorded was 29 June 2022, at 1.59 milliseconds less than 24 hours.[26] In a 2024 paper published in Nature, Duncan Agnew of the Scripps Institution of Oceanography projects that the water from increasing ice cap melting will migrate to the equator and thus cause the rate of rotation to slow down again.[26]
- imglorp 8mo agoResponding to a deleted comment: > ... the "invisible infrastructure" of the web; balancing historical accuracy with the technical need to minimize zone fragmentation is a much more complex trade-off than it appears on the surface ... The complexity goes up tremendously if some condition is rarely encountered: eg leap second. This means it gets pushed to a "corner case" and tested more lightly and more rarely. At $work around 2014 we had three different hardware GPS types which we used for precision timekeeping; some chips, daughterboards, and firmware. One day a leap second arrived -- it gets broadcast to aGPS hardware a day ahead of time -- and all three implementations handled it differently. One handled it, one did something else like ignore it, and I think one even bricked itself. That situation was less than bueno.
- throw0101d 8mo ago> The complexity goes up tremendously if some condition is rarely encountered: eg leap second. This means it gets pushed to a "corner case" and tested more lightly and more rarely. There is some talk of eliminating the leap second, which would over time have the Earth and sun diverge with regards to noon and such. One 'answer' to this concern is to have a 'leap hour' or something in the future (some future generation's problem, not ours): but given that people can't even get February 29th correct now, and it happens regularly, I don't see how a one-off event would be made to work. It'd be a huge coördination problem. Just look at the introduction of the Gregorian calendar: it was slightly off since the time of Julius Caesar, but that minor error added up over time, to the point that to get the equinoxes/solstices back to where they 'should' be 10 days had to be removed with the Gregorian calendar. And because of politics (or a religious flavour) it took a long while for everyone to get on the same page.
- tialaramex 8mo agoThe calendar adjustments are because the planet's constant orbital period isn't a whole number of days. The leap seconds were an attempt to have wall clock time map to the planet's rotational angle consistently despite the problem that the planet's spin varies unpredictably. Yes the "leap hour" is a legal fiction of course. In reality in the event anybody cares about this in the distant future they will make the kind of "drastic" changes you've probably experienced twice a year for your whole life and barely noticed... More likely because the drift is so incredibly slow they won't change anything.
- throw0101d 8mo agoThere was some talk about a negative leap second† a few years ago: * https://www.npr.org/2024/03/30/1241674216/climate-change-time-negative-leap-second https://www.npr.org/2024/03/30/1241674216/climate-change-tim... † T23:59:58Z would have skipped/suppressed :59 and gone to T00:00:00Z.
- netsharc 8mo agoYou make it sound like time labels like "23:59:58Z" can perform actions (e.g. to skip or "suppress"). I had to look it up: https://www.timeanddate.com/time/negative-leap-second.html https://www.timeanddate.com/time/negative-leap-second.html . In proper words, the clock ("the one humanity agrees to use) would skip 23:59:59Z. I wonder how much chaos a minute that only has 59 seconds would cause. Measurements would be off by that missing second (e.g. a pipeline delivering fuel at 60 liters/minute would surprisingly only have 59 liters in that minute..).
- throw0101c 8mo ago> I wonder how much chaos a minute that only has 59 seconds would cause. The FreeBSD folks test(ed?) their code for these things and it works: * https://lists.freebsd.org/pipermail/freebsd-stable/2020-November/092837.html https://lists.freebsd.org/pipermail/freebsd-stable/2020-Nove... Of course third-party userland code understanding what happens is another thing.
- wahern 8mo agoNobody should be using an API like time(2) or clock_gettime(2)+CLOCK_REALTIME to measure event durations with sub-second precision or accuracy, especially when controlling mechanical equipment. And I'd be absolutely surprised if anybody was when controlling equipment, at least in a regulated industry. On unix this is what CLOCK_MONOTONIC is for; for one thing, the real-time clock can be reset at any time. Technically even CLOCK_MONOTONIC could jump forward. Real-time embedded systems either provide other timing APIs, or make additional guarantees about CLOCK_MONOTONIC's behavior.
- 8mo ago
- SeanDav 8mo agoI assumed that leap seconds could be determined algorithmically, it appears I assumed badly. This is a bit of a can of worms...
- toast0 8mo agoThey basically are, the algorithm is something like: At the beginning of january and july, observe the difference between UT1 and UTC. If the difference is >= 0.6s, a leap second will be inserted at the end of june/december. Publish the results here: https://hpiers.obspm.fr/eoppc/bul/bulc https://hpiers.obspm.fr/eoppc/bul/bulc
- pocksuppet 8mo agoThis is true. They look at how much the earth spun, and whether it was more or less than 86400 seconds/day average. This can't be done without external data. It's not a pure mathematical algorithm.
- xg15 8mo agoWaiting until Trump discovers that the earth rotation service exists and forces them to insert a negative leap second just because he can.
- jmusall 8mo agoThen, when the stock market crashes due to software failures and timing inconsistencies, he'll want to undo it and thereby cause even more chaos ;)
- treis 8mo agoOh thank God I thought I was going to make it through a thread on leap seconds without a political discussion
- arduanika 8mo agoIs it that surprising? Elsewhere in the thread, people are discussing the best smear tactics!
- Vvector 8mo agoLeap Seconds need to be abolished. The only people who need it are Astronomers. They could just use an offset. Implementing leap seconds correctly is a huge burden, for no gain. Where I live, high noon today occurs at 1:03 PM. No one is complaining that it is 3 minutes (or 63 minutes) off. It's a non-issue for 99.9% of the population.
- coldpie 8mo agoHmm. I understand that perspective, but I'm not sure I agree. It does seem to matter over a relatively short & realistic time scale. According to the Wikipedia page, there have been 27 seconds added since 1972, which is only 44 years ago. At that rate, that's about 1 minute per 100 years. We have many systems that have existed for several centuries and I think it's not unreasonable to start making plans for systems that may exist for millennia, where you're starting to talk about a 10+ minute offset at the current rate. But I do think there is a valid argument that the infrequency of these events cause more issues than maybe one large adjustment 500 years from now would cause. Not sure where I land on this one.
- 8fingerlouie 8mo ago> since 1972, which is only 44 years ago Thanks for making me a decade younger :)
- ralferoo 8mo agoThe problem is that Earth's rotation isn't consistently faster. Some years leap seconds need to be added, some years they need to be removed. Would be far better to leave them alone, let them average out, and as the GP said let the people who care about this add the offset they need.
- coldpie 8mo ago> Some years leap seconds need to be added, some years they need to be removed. Is that true? Per Wikipedia: > Since [1972], 27 leap seconds have been added to UTC, with the most recent occurring on December 31, 2016. All have so far been positive leap seconds, adding a second to a UTC day; while a negative leap second is theoretically possible, it has not yet occurred. Either way, it's due in part to Earth's rotation slowing down, so the average drift would still be non-zero.
- himata4113 8mo agoHow about a leap minute instead so we only have to worry about this when it's not a problem anymore :)? We will either hit the fermi filter or accend intelligence.
- layer8 8mo agoThe length of day increases by around 1.7 milliseconds per century long term (due to the moon’s gravity continuously slowing down Earth’s rotation), which without leaps seconds translates to around one total minute per century. Note that this is cumulative: next century you will need two leap minutes, and so on. Of course, there are significant shorter-term variations in Earth’s rotation due to other factors, so it isn’t quite that smooth in practice. There was a resolution in 2022 to make a decision in or before 2035, to increase the allowable deviation from one second to a longer interval, like one minute. But that would become more frequent in the long run as well, and likely would still cause disruptions whenever it happens. Though on the other hand there would likely be a longer advance notice for it as well.
- himata4113 8mo agoI think in 100 years more or take if the exponential curve doesn't level off we're gonna each near super intelligence and some form of fusion at minimum. At worst we just eradicate ourselves.
- wmf 8mo agoThat's much worse than the Y2K problem.
- himata4113 8mo agoThe idea is that we've advanced so far that it is simply not a problem anymore.
- alentred 8mo agoI would rather suggest a contrary: do smaller increments more frequently. This way it is easier to test and if something goes wrong you know it quicker. Kind of like running your CI pipeline on every commit vs nightly. Going to millisecond adjustments seems, however, very impractical.
- sltr 8mo agoNext up: DOGE cancels leap seconds. /s
- idiotsecant 8mo agoWe should just have a standards body that meets each decade and decides what epoch time every day for the next 10 years officially starts on. Everyone knows ahead of time how it will work, software updates have predictable change intervals, it allows us to refresh time based on policy decisions, and it uses something sane as the backbone of the system.
- SchemaLoad 8mo agoEvery 10 years is just the right frequency that most software breaks, but it causes frequent pain for everyone. Switching to leap hours that have to be dealt with every few thousand years would be much preferable.
- OhNoNotAgain_99 8mo ago[dead]
- wanhandle 8mo agoBack in the early 2010s my company was maintaining a Spring application processing ActiveMQ messages. We'd received word that the application wasn't processing work. One of us goes and looks at logs and sees just endless volumes of stack traces. Eventually the suggestion is made and accepted to just reboot the application. That fixed it. Turns out the JVM simply lost its mind when leap seconds were introduced. So, for the next several years, we watched that French society's website that announced when leap seconds would be introduced and scheduled application restarts accordingly.
- deleted 8mo ago[deleted]
- rappatic 8mo agoGoogle and lots of other firms use a "leap smear" to hide the leap second from end users, essentially "smearing" the second across the hours before and after each leap. https://developers.google.com/time/smear https://developers.google.com/time/smear
- MarsIronPI 8mo agohttps://xkcd.com/2266 https://xkcd.com/2266
- fuoqi 8mo agoComputer systems (most importantly, UNIX) should've been using TAI [0] from the beginning. Human-readable time in turn should be computed from it using periodically updated time zones database which would include offset between TAI and UTC. By eliminating leap seconds we effectively re-invented TAI with a weird offset. While I am in favor of eliminating leap seconds as a hacky way to fix the current mess, it's sad to see that we added yet another quirk to the already complicated system of datetime keeping. [0]: https://en.wikipedia.org/wiki/International_Atomic_Time https://en.wikipedia.org/wiki/International_Atomic_Time
- theamk 8mo agoNo, they should not. We convert timestamps to and from date+times all the time. Having each day be exactly 86400 seconds simplifies this a lot, and practically every app benefits from that. Leap second smearing will ensure smooth and continious time. Taking leap seconds into account is only needed in a very, very few contexts - maybe astronomy, or certain kinds of high-speed physics? Those rare users should be able to figure stuff out. Go with UTC, don't optimize for rare usecases at the expense of everyone else.
- fuoqi 8mo agoYou clearly do not know how much havoc and complexity leap seconds introduce into various systems. This is why leap seconds are likely to be phased-out [0]. It's effectively an admission that use of leap seconds in the "base" time was a mistake. >We convert timestamps to and from date+times all the time. If you do not account for time zones during this conversion, then you are not qualified to implement such conversions. It's fine to use 86400 seconds for durations (e.g. "this computation will finish in 1d 8h 20m 34s"), but it's absolutely not fine to use it while dealing with datetimes. [0]: https://en.wikipedia.org/wiki/Leap_second#Phase-out_and_future_of_leap_seconds https://en.wikipedia.org/wiki/Leap_second#Phase-out_and_futu...
- klausa 8mo ago>Having each day be exactly 86400 seconds simplifies this a lot, and practically every app benefits from that. Making an assumption that a day 86400 seconds breaks at least twice a year in many parts of the world, and that's before we introduce leap seconds or possibility of your code running on hardware that itself travels across timezones.
- unit149 8mo ago[dead]
- arwineap 8mo agoI thought the state of the art here was to elongate seconds collectively over the course of a long range of time to compensate
- sarchertech 8mo agoThe idea that if being dark at 12pm in 20k years will bother anyone is absurd. The shift will happen so slowly that the only people who will even realize it happened are historians and history buffs. Really the idea that there will enough civilizational continuity that our current timekeeping infrastructure and systems will continue unbroken for that long is insane.
- al_borland 8mo agoChanging a global time system is not a trivial task. We’re still using a calendar developed over 400 years ago and just making minor tweaks. Without some central global authority, change is unlikely. And even with that, it would be extraordinary disruptive. The middle for the day, on our time keeping devices, being light outside goes all the way back to the first sundials over 3,000 years ago. Small and regular maintenance is more realistic than expecting a complete overhaul of timekeeping at some point when are lack of maintenance becomes so problematic that the whole system needs to be thrown away.
- deleted 8mo ago[deleted]
- fuoqi 8mo ago>The middle for the day, on our time keeping devices, being light outside goes all the way back to the first sundials over 3,000 years ago. Most of the world is perfectly fine with 12:00 not being synchronized with high noon [0]. And some jurisdictions still semiannually f*k with it further using DST. Generously assuming the current time keeping system will survive for ~6k years (looking at the leap seconds accumulation rate for the last 50 years) we can just shift timezones by one hour. [0]: https://64.media.tumblr.com/4a9a4613f057d3b5f17ec548e6ac06d1/aaca3f3d940ef33f-fc/s1280x1920/34bd493695cd2b39bfd5755240f2b8e0adb49330.png https://64.media.tumblr.com/4a9a4613f057d3b5f17ec548e6ac06d1...
- sarchertech 8mo agoWe’re talking 20k-50k years before the 12pm is no longer light outside. Do you know how long that is on a civilizational scale? When we try to develop warnings for nuclear waste storage that will last that long it’s mostly impossible because we assume there will be absolutely no civilizational continuity/shared context. Doing 20k years of regular maintenance just in case we somehow keep using the same timekeeping system is completely unhinged. Better to jump an hour in 6k years if people in 6k years decide they care.
- saltyoldman 8mo ago[flagged]
- Xunjin 8mo agoYou need therapy ASAP.
- Ozzie_osman 8mo agoThe worst bug I ever dealt with in a 20 year career was a leap second bug (back in 2012). Servers all slowed down dramatically very suddenly, CPU saturated. No relevant code changes or changes in traffic. Turns out, they just got into that state due to a leap second. Some Livelock bug. A restart fixed everything. It wasn't just our site that went down. If I recall correctly, many other large sites (like Reddit, LinkedIn, etc) also had the same issue. Guess no one thought of the "did you try restarting it?"
- rausr 8mo agoI remember that well (because my manager at the time was asking me afterwards "why were you up at 2 in the morning restarting services?" and didn't believe my answer :( )
- darkwater 8mo agoYep, I was there too! HN thread from the time: https://news.ycombinator.com/item?id=4188412 https://news.ycombinator.com/item?id=4188412
- rwky 8mo agoMe too! In my case postfix locked up and stopped sending mail there was a massive queue. I checked the logs and saw the same second twice and that's when I learned about leap seconds. Since then I have a reminder in my calendar every 6 months to check if ones been announced. Thankfully we've only had two.
- NooneAtAll3 8mo agoall I want for christmas is a negative leap second https://qntm.org/leap https://qntm.org/leap