8 ms·
June 30th 2012 will be 1 second longer: 23:59:60
- JonnieCache 14y agoAt midnight on NYE 2008/9 we dialed up the speaking clock, and there actually was an extra beep. It was pretty cool, and we felt a brief moment of existential nausea when we suddenly felt our size in relation to the solar system. (I'd like to point out that after that we did go to a massive party.)
- 27182818284 14y agoI think this announcement is a bit dated. I thought it went back into debate?
- oasisbob 14y agoPerhaps you're thinking of the proposal to abolish the leap second entirely? http://www.bbc.co.uk/news/science-environment-16625614 http://www.bbc.co.uk/news/science-environment-16625614 The parent link is to the authoritative Bulletin C, hard to imagine that it's wrong.
- excuse-me 14y agoNo it was rejected. Although it's always possible that the USA will unilaterally ignore cheese-eating surrender monkey time and adopt "freedom time"
- sp332 14y agoIt was deferred, not rejected. And France is on the same side of the issue as the USA (they don't like leap seconds).
- derrida 14y agoInteresting to note that China has something like "freedom time". If you are in the west of the country, the sun rises at 9am and sets around 9pm, when in the east it rises at 6am and sets at 6pm. The entire country is on one time, Beijing Time, despite it stretching 3 time zones & Beijing being close to the eastern extremity.
- jessriedel 14y agoThe wikipedia article on International Atomic Time is worth reading. http://en.wikipedia.org/wiki/International_Atomic_Time http://en.wikipedia.org/wiki/International_Atomic_Time
- rayanm 14y agoThat should give me more time to submit a conference paper on June 30.
- DanWaterworth 14y agoI wonder how many people will be woken in the middle of the night by bugs caused by this.
- freehunter 14y agoAt least on Cisco systems, you can add a leap second [1], and at least on my network the tolerance is set at 5 minutes. So network time should still be working. For clients that might not know how to deal with a leap second but still poll network time, I only see issues in the rare case that the client polls the server at exactly 23:59:60. In that situation, they might poll back again to grab a new time thinking it's wrong. Of course there will always be outliers and poorly coded applications that rely on time, but at least it's not a Y2K style situation. [1] http://www.cisco.com/en/US/tech/tk869/tk769/technologies_white_paper09186a0080117070.shtml#assnmodes http://www.cisco.com/en/US/tech/tk869/tk769/technologies_whi...
- scorpion032 14y agoYup. Gain 1 second. Lose hours debugging the problems that causes. Not worth it. :P
- dllthomas 14y agoAmusing, but the issue is not really gaining or losing seconds, but keeping the clock synched to the rotation of the Earth. As long as we're going to all the trouble of dealing with timezones to make sure our wall clocks have a roughly consistent relationship to when the sun is in the sky, we should be doing this kind of thing as well.
- excuse-me 14y agoThat's what they say when they steal an hour of my sleep every spring!
- btilly 14y agoNo we shouldn't. If everything was done perfectly, then on average your timezone is already out of whack with local solar time by about 15 minutes or so. Of course we don't do it perfectly, most of us jump another hour back and forth each year for no particularly good reason. Who cares about another second? Just let solar and calendar time drift apart. The amount of time until a timezone is noticeably out of whack with solar time is substantially longer than how long timezones have existed in anything like the modern form. In a thousand years maybe we'll start moving timezones around. But the cost of moving them for astronomical reasons will happen orders of magnitude less often than moving them for random political reasons. I have read arguments both ways. And I remain convinced that letting UTC slowly drift away from Greenwich is a perfectly reasonable solution that will save us from many potential software bugs, and will cause no significant disruptions in life for the next ten thousand years. Of course eventually the Earth's rotation will slow down enough that the drift of time zones will become noticeable on a human time scale. But that problem is many thousands of years off, let them solve it then. If all goes well they will have had to figure out how they want to handle local calendar time not fitting UTC for people living on asteroids and other planets, and can just adapt that solution to Earth...
- molmalo 14y agoNice! One more second before my next birthday! Oh, I've lost a few more writing this... Cant we add an hour or so, so I can take a nap?
- SeoxyS 14y agoI wonder what the impact is on computers. Will your server know to add another second, or will it just lose sync and be one second off for the rest of times?
- throwaway64 14y agoit will just sync via NTP, and assume the "difference" was regular clock skew.
- mbq 14y agoAt least UNIX time is sane enough not to count this madness, so all time differences are objective; only one timestamp value will ambiguously mean (-1):60th and :00th second in UTC.
- aphyr 14y agoPOSIX time will jump discontinuously backwards after the leap second, counting: 59.50 59.75 60.00 60.25 60.50 60.75 60.00 Or, if your clock implementation is not POSIX-compliant but follows Mills' paper instead: 59.50 59.75 60.00 59.25 59.50 59.75 60.00 It gets weird, though: since this information was only made available recently, your computer may not know the leap second exists. In that case, its upstream NTP servers will jump and the local ntpd will slew the clock smoothly over the discontinuity, IIRC. OTOH, if your system is aware of the leap second and if you're using the system clock to calculate intervals (i.e. t2 - t1), expect possibly negative or zero intervals over this timeframe. If you're calculating rates over a roughly 1-second interval, divide-by-zero bugs are definitely possible. On a related note, does anyone know what the Oracle and OpenJDK JVMs do with respect to System.currentTimeMillis? They claim it's number of seconds since the epoch, which would imply this timer will not encounter discontinuities. The only ways I can think of to achieve that are by reading the system clock state to look for the leap insert/del/doublecount flag, or read a copy of the leap second table. [edit] You may be asking, "Why would anyone use a system of time in which two numbers could refer to the same instant, or one in which a given number could refer to no time at all? Why not use a time system in which you could subtract two times from each other to get the interval between them? Or hell, even a time system where time always increases, you know, so we could order events. The closest thing we have to such a time scale is TAI (http://en.wikipedia.org/wiki/International_Atomic_Time http://en.wikipedia.org/wiki/International_Atomic_Time), which is what most computer systems like to pretend their clocks are: "the number of seconds since an epoch". UTC and POSIX time are adjusted, relative to TAI, to keep the number of seconds in a given day at a nice "easy" 86400, which is why we're in this mess. Given that it takes plenty of math to translate a number like 1339696998.435347 into a human-readable date, I think our computers should just be keeping TAI to begin with and make the whole process easier on ourselves; but so many systems assume UTC or POSIX time that we're stuck with it.
- deleted 14y ago[deleted]
- aphyr 14y agoEr, actually the posix times will be big numbers like 1339696578.75 1339696578.00 and so forth. I just called them 60 so you'd know which "second" was which.
- acomjean 14y agoThank goodness I don't have to work on time anymore. Zulu time, sidereal_time, UTC, GPS Time... Phone calls from work at odd hours.. I do like GPS time. It keeps going at a constant rate like all good time should. Time differences are easier in GPS, you don't have to worry about pesky leap seconds.... Sidereal time is the most interesting from a cosmic sense.
- rmc 14y agoThis happens about every 1½ years. It is also the reason why posix/epoch time is not the number of seconds since 1970.
- mschalle 14y agoI'm guessing my iPhone alarm will break again?
- tazzy531 14y agoHow Google handles leap seconds (by lying to the software): http://googleblog.blogspot.com/2011/09/time-technology-and-leaping-seconds.html http://googleblog.blogspot.com/2011/09/time-technology-and-l...
- Trufa 14y agoThat is pretty awesome if you ask me!
- adamsmith 14y agoWhy use cosine to interpolate v.s. a linear smear?
- excuse-me 14y agoVery good question. I can only think it's too randomize it a little so you don't end up changing clocks only by powers of 2 and showing up some weird bug.
- ajross 14y agoThe cosine is pretty much the perfect interpolation function when you want the derivatives to be zero at the boundaries. It's by definition frequency-bound (to itself, of course). It's derivatives are defined and continuous to any degree you want. And it's easy to express and understand. You pick other functions only when it's too expensive.
- ThisIsADogHello 14y agoProbably to minimise the error inbetween updates. If the clock rate changes suddenly, then after that moment, any clocks based on the old rate will become increasingly wrong. but, if the skew starts off slow, begins to change rapidly, and then slows and stops again, then clients won't need to be immediately aware of the clock skew and will be less wrong.
- bajsejohannes 14y agoDoes anyone know where you can subscribe to future leap second announcements?
- acomjean 14y agoWe were in the US so we used to get it from the Naval observatory. http://www.usno.navy.mil/USNO/time/master-clock/leap-seconds http://www.usno.navy.mil/USNO/time/master-clock/leap-seconds they get if from IERS http://www.iers.org/ http://www.iers.org/ They issue leap second guidance to about 1 year in the future. They adjust typically twice a year as needed (Jan 1 and July 1).
- dhimes 14y agoWas looking up mine while you posted yours. Yours looks like it gives more advance notice. I'm religiously opposed to deleting posts, however, so I'll just upvote yours.
- excuse-me 14y agoI like the name "International Earth Rotation Service" - I always picture some dusty cavern with a giant brass gear wheel and a little old guy coming in with a key every day to wind it up.
- JonnieCache 14y agoGood isn't it. It's the "service" that really makes it I think.
- adavies42 14y agothey should replace the gears with tighter tolerance ones then and clear this up permanently
- dhimes 14y agoI received word through a listserve from the coastguard http://cgls.uscg.mil/ http://cgls.uscg.mil/ Once you agree to the security whatever go to 'hosted groups.' I subscribe to 'Notice Advisory Navstar Users,' which issues reports about GPS updates. They notified us 30 May 2012. Edit: acomjean looks to have a better source (but if you are looking to subscribe to the Local Notice to Mariners in your district, which I strongly encourage if you boat on the ocean, my links will get you there too!).
- RedwoodCity 14y agoI look forward to the extra second of sleep.
- cdooh 14y agoIt's only one second, while quite interesting I don't see why this matters
- excuse-me 14y agoYou mean why it matters that we have leap seconds (it doesn't and they should be abolished) or why the news of it matters (because a 1000 crappy time implementations are going to walk off the end of buffers and do weird things) ?
- cdooh 14y agoWhy it matters that we have leap seconds. It is just one second and it happens randomly based on several factors
- excuse-me 14y agoReally it doesn't - people just have this attachment to days and the sun for telling the time. The only people that a leap second realistically affects are astronomers and they are more than capable of managing their own time software. At roughly 1 second every 1.5 - 2 years it will be a couple of millenia before the sun even gets an hour away from local noon - and people manage with daylight savings time. So every 2000years we might need to introduce a leap hour.
- mjn 14y agoIt's even worse than that, because solar noon is already different from local noon almost always, almost everywhere. First, you have to be precisely in the middle of a timezone, and not one of those weird timezones that doesn't actually follow the lines of longitude, either. Otherwise you're skewed late or early relative to solar time. Secondly, solar noon even at the precise center of timezones is only local 12:00 on average, because the timing of solar noon vis-a-vis a 24-hour clock fluctuates through the year by up to 18 minutes. Two factors are involved: the Earth's orbit is slightly eccentric, and Earth's axis of rotation isn't precisely perpendicular to the plane of its orbit (http://en.wikipedia.org/wiki/Equation_of_time http://en.wikipedia.org/wiki/Equation_of_time has details and a graph). So all the leap seconds do is keep the average local noon, at precise centers of timezones, equal to solar noon.
- FootballMuse 14y agoShould I get more sleep, or should I wake up earlier? decisions decisions....
- deleted 14y ago[deleted]
- pooriaazimi 14y agoA hackerish question: how can you take advantage of it? Say, in stocks or online transactions? (I haven't got time to read the article right now (but will do in a week when I'm less busy) and have little to zero experience with times, so forgive me if it's something that's been discussed in the article. I'm just curious.)
- rmc 14y agoAlmost certainly not. Remember this happens about every 1½ years, so this has happened a few times recently. I cannot see how you could take advantage of it, since it's the sort of edge case that you'd presume the designers of stock markets would know about.
- TazeTSchnitzel 14y agoSSL certs or something, maybe?
- vlisivka 14y agoSSL certs issued at :60 may have problem with validation. Just reissue them.
- TazeTSchnitzel 14y agoI guess that's not very interesting, then :/
- mck- 14y agoTime is relative.
- ChuckMcM 14y agoI think it would be an interesting PR campaign to ask people what they would do with 1 more second. if time is money, how much money do we inject when we add a second to the year? Of course we wouldn't have this problem if we just counted seconds from some particular point in space time moving forward. Who cares if the Sun is exactly overhead at noon anyway :-)
- deleted 14y ago[deleted]
- capkutay 14y agoHow often does something like this (days that last longer/shorter than 24 hours) happen?
- sneak 14y agoThey are always longer. The Earth's rotation is slowing.
- tankenmate 14y agoUmm, actually no. On average the rotation is slowing, but sometimes there are local speed ups.
- 3pt14159 14y agoGuys do the right thing. If your app is very sensitive to bad data (say financial) just throw up a temporary "down for quick maintenance" page for a couple of seconds and you are good to go.
- btipling 14y agoDowntime affects SLAs and there isn't a lot of breathing room depending on your 9's[1]. In addition, bringing something down has its own problems and are you just advocating bringing down the user interface or should everything get shut down, like the entire stack? All the services, queues, databases, block storage, etc? [1] http://en.wikipedia.org/wiki/High_availability#Percentage_calculation http://en.wikipedia.org/wiki/High_availability#Percentage_ca...
- vr000m 14y agoThe document: http://transition.fcc.gov/ib/sand/irb/weritacrnc/archives/nc1893wp7a/1.doc http://transition.fcc.gov/ib/sand/irb/weritacrnc/archives/nc... tells implementers how to handle events around the leap second. There is some discussion in the ITU-T to all together remove the leap second (but that decision will be taken only before the next leap second).
- DrewChambersDC 14y agoI'm as big an astronomy geek as anyone else, but this is so pointless. Why bother wasting time and effort with this? Just let the discrepancies accumulate and adjust 6 seconds every 10 years or so. It would save everyone a little bit of effort, and you could make an event out of it.
- Angostura 14y agoIf it only happens every 10 years, software developers are likely to forget about it. Hello a batch of crashing systems every 10 years. When it happens every 1.5 years there's a trickle effect - only systems introduced in the last 1.5 years will have trouble and developers are more likely to remember to factor it in.
- michaelochurch 14y agoI can't see the point of having leap seconds, and here's why: we already tolerate so much (intrinsic) inexactness in the relationship between solar noon and clock noon (ignoring daylight saving time, which I actually like even knowing that it's somewhat ridiculous) that it seems silly. First, there's the equation of time: solar noon isn't the same clock time every day anyway: it varies by +/- about 15 minutes during the course of the year. Second, we live in time zones set for arbitrary reasons. For example, the average solar noon in New York is 11:55, not noon. I could understand inserting leap seconds if there were some specific need to have 0 longitude be at solar noon at exactly 12:00:00, but as far as I can tell there's not. If the clock drifts off solar noon by a half-second per year or so, then maybe in a few millennia London will decide to use UTC-1. I could be wrong about this, but I don't see this as a big deal.
- IsTom 14y agoAstronomers and physicists care a lot about this and they are the people running the clocks.
- philf 14y agoWhat's the point of this adjustment? Currently there is an offset of -34 seconds between TAI and UTC and aftwards it will be -35. Seems pretty random to me...
- bporter 14y agoI plan on using the extra second to read more Hacker News blog posts!
- bporter 14y agoYES! I PLAN ON USING THE EXTRA SECOND TO PLAY WORLD OF WARCRAFT AND READ MORE HACKER NEWS BLOG POSTS.