Slashdot Mirror

← Back to Stories (view on slashdot.org)

New US Atomic Clock Goes Live

Posted by samzenpus on from the in-real-time dept.

PaisteUser (810863) writes with news about a new, hyper-accurate atomic clock unveiled by the National Institute of Standards and Technology. "A new atomic clock, so accurate it will lose or gain only one second every 300 million years, was unveiled Thursday by the National Institute of Standards and Technology, a branch of the U.S. Department of Commerce. The NIST-F2 had been in development for about a decade and is three times more accurate than the F1, which has been in use since 1999. The institute will continue operating both clocks for now at its campus in Boulder, Colorado."

86 of 127 comments (clear)

  1. Ah another seemingly benign NIST approved standard by bazmail · · Score: 3, Funny

    I wonder what backdoor the NSA has built into this.

  2. How, exactly, do we know? by mythosaz · · Score: 1

    What do we have to reference it against, and isn't it arbitrarily exactly correct?

    How the hell would we know if it was wrong?

    1. Re:How, exactly, do we know? by Kenja · · Score: 1

      It is the reference. Time is relative, we use these atomic clocks to set standards for comparison.

      --

      "Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
    2. Re:How, exactly, do we know? by fizzer06 · · Score: 1

      I guess it's "good enough for government work".

    3. Re:How, exactly, do we know? by grub · · Score: 3, Funny

      Every day at noon they compare it to the sundial out back.

      --
      Trolling is a art,
    4. Re:How, exactly, do we know? by schneidafunk · · Score: 3, Interesting

      Even if it is arbitrary, we can use it for synchronization as long as every relies on it as the standard.

      FTA:
        "If we've learned anything in the last 60 years of building atomic clocks, we've learned that every time we build a better clock, somebody comes up with a use for it that you couldn't have foreseen," says physicist Steven Jefferts, lead designer of NIST-F2.

      --
      Some people die at 25 and aren't buried until 75. -Benjamin Franklin
    5. Re:How, exactly, do we know? by bazmail · · Score: 2

      If it is the reference then making claims about its accuracy is surly redundant?

    6. Re:How, exactly, do we know? by Anonymous Coward · · Score: 1

      I dunno, it rather seemed politely redundant to me. Not threatening at all.

    7. Re:How, exactly, do we know? by aaron4801 · · Score: 2

      And what, exactly, is the point if they have to reset it every year or two anyway due to leap seconds?

    8. Re:How, exactly, do we know? by Anonymous Coward · · Score: 1

      The accuracy referred to is the measurement uncertainty of the instrument. Imagine you built ten of these clocks, and put them in adjacent rooms. The accuracy can be considered to be the mean drift between the clocks over time.

      This is an over-simplification, because it is infact measured by comparing the clock to other atomic clocks distributed across the world, each of which is adjusted by taking known relativistic effects and other biases into consideration, and they are non-linearly averaged to create UTC (coordinated universal time), and the deviation from UTC is considered the accuracy of the clock in question.

      In practice the accuracy of these clocks is calculated before they are even built, reasoning from known physical laws and taking into consideration the uncertainty principle.

      What is important about atomic clocks is that they do not have intrinsic aging. With a mechanical clock (including quartz and silicon resonators), the frequency standard is based on a mechanical artifact which degrades over time. With an atomic clock, even the off-the-shelf rubidium oscillators, you are instead measuring an atomic physical phenomenon (the H=0 hyperfine ground state transition of Rubidium and Caesium respectively), so while the clocks count may deviate due to uncertainty and noise and wrong-mode operation (strong magnetic fields will cause this), the frequency will remain constant until the Rb flash tube fails, or in the case of a fountain clock, the clock runs out of Rb/Cs.

      Hydrogen masers actually have a smaller linewidth (spread of frequency output) than atomic clocks, and are thus used in astronomy and physics for distributed coherency and synthetic aperture applications, but the inferior noise floor of them means they have worse long-term accuracy.

    9. Re:How, exactly, do we know? by rgbatduke · · Score: 1

      Sadly, AC or not, I would have modded this up if only my mod points hadn't disappeared today.

      rgb (and don't call me Surly...)

      --
      Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
    10. Re:How, exactly, do we know? by Tony+Isaac · · Score: 1

      It is, actually, possible to measure such things.

      Consider GPS, which relies on the accuracy of atomic clocks in orbit. Each GPS satellite has its own independent clock, which must be accurate to within about 40 billionths of a second, over the life of the satellite. http://gpsinformation.net/main... If the accuracy of one of the satellites' clocks is greater than that threshold, your GPS unit will incorrectly report your location. The accuracy of GPS coordinates is one way to calculate the accuracy of the atomic clocks in orbit. Multiply the error rate (in billionths of a second) times the life of the clock, and you can arrive at a number of years it will take for the clock to be 1 second off.

      Similar types of calculations can be done with these new, faster clocks. No, it's not necessary to wait 300 million years to see if the clock is one second off. That number is simply an extrapolation.

    11. Re:How, exactly, do we know? by hyperfine+transition · · Score: 2

      Not sure if the parent is simply being funny, but ...
      No atomic clock is ever 'reset' because of leap seconds. All they produce is a one-pulse-per-second 'tick'. The labels on those ticks are completely arbitrary. When a leap second occurs, you just change the labels ...

    12. Re:How, exactly, do we know? by AmiMoJo · · Score: 1

      Atomic clocks work by counting the vibrations of atoms. We can determine how good the clock is at counting the vibrations, and from that calculate how much error it will see over time. It's done with statistics, i.e. how likely the clock is to miss a vibration.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
  3. Re:Ah another seemingly benign NIST approved stand by Ralph+Wiggam · · Score: 1

    Ahhh...Slashdot...where the first post for literally any submission is likely to reference NSA backdoors.

  4. So... by minipulator · · Score: 3, Insightful

    How do I point ntpdate to it?

    1. Re:So... by HunterZ · · Score: 1

      I want to know that same thing, but for the cluster of ntpd servers running on my LAN.

      --
      Arguing about vi versus Emacs is like arguing whether it's better to make fire by rubbing sticks or banging rocks.
    2. Re:So... by msauve · · Score: 1

      Indirectly, via a GPS refclock.

      --
      "National Security is the chief cause of national insecurity." - Celine's First Law
    3. Re:So... by sexconker · · Score: 1

      I want to know that same thing, but for the cluster of ntpd servers running on my LAN.

      I'd help you but you didn't specify you were running a Beowulf cluster.

    4. Re:So... by devman · · Score: 1

      List of NIST time servers here: http://tf.nist.gov/tf-cgi/serv... If you want to be a good NTP citizen you probably shouldn't use these servers directly though, unless your running a very large network and syncing your own ntp servers. Some ISPs run time servers on their gateways or DNS servers, it is a decent way to get an NTP sync that is "network close" to you.

    5. Re:So... by aliquis · · Score: 1

      It's dark outside.

      It's night.

      This wouldn't help me get to bed earlier anyway so why bother. (~04:42 local time as if it matters.)

    6. Re:So... by chuckinator · · Score: 1

      ntpdate wwv.nist.gov

    7. Re:So... by hyperfine+transition · · Score: 1

      The receiver might cost $60 an antenna suitable for permanent outdoor installation might cost the same, but running cable to the roof, assuming that's possible, could easily cost a few thousand dollars to do properly. You'll want lightning protection too, if you're running the antenna cable down in to your server racks.

      But for nearly everyone, as others point out, the 10 ms or so accuracy you will get from a nearby NTP server, is more than enough.

    8. Re:So... by unixisc · · Score: 1

      In Windows 7, go to 'Change Date & Time settings', click on the 'Internet Time' tab, then 'Change settings', and in the text box, where you normally see 'time.windows.com', you can change it to 'time.nist.gov'.

      For any of the unixes, I'm guessing you'd have to edit some file in /etc to get that going.

  5. so the new clock is 3x as accurate as the old one? by CrimsonAvenger · · Score: 4, Funny

    Well, it's important to me to be accurate within one second every three hundred million years!

    Not sure how I'd manage if my time was only accurate to one second in ONE hundred million years....

    --

    "I do not agree with what you say, but I will defend to the death your right to say it"
  6. Still waiting for the rice grain sized Atom Clocks by InsultsByThePound · · Score: 1

    You know, the ones that will enable gps devices to be accurate to a few centimeters. That will allow robotic lawnmowers without wiring up the borders on the property, drones to airdrop missiles or fast food on my front door. Stuff like that. So what will this be good for?

  7. Mod parent up by schneidafunk · · Score: 1

    Exactly, this will be the standard for all other time standards. Just like they have their standard kilogram stored in a vault in france for reference: http://www.wired.com/2013/01/k...

    --
    Some people die at 25 and aren't buried until 75. -Benjamin Franklin
    1. Re:Mod parent up by alexander_686 · · Score: 3, Informative

      No, the weight of a kilogram is completely arbitrary. They are trying to fix it to something but right now it is just a weight.

      A atomic clock works by counting the vibrations in an atom. The atomic clock fails when it miscounts the vibration of an atom, causing the error. The new clock is so good at counting that errors rarely occur.

    2. Re:Mod parent up by schneidafunk · · Score: 1

      They are trying to fix it to something but right now it is just a weight.

      Kilograms are a weight.

      --
      Some people die at 25 and aren't buried until 75. -Benjamin Franklin
    3. Re:Mod parent up by msauve · · Score: 1

      Kilograms are units of mass, not weight ( that would be Newtons, which is a force).

      Errors are not caused by "miscounting," but due to the fact that no physical realization can be perfect. The second is defined under the conditions of zero acceleration (i.e. no gravity) and at a temperature of absolute zero, neither of which are attainable in practice.

      --
      "National Security is the chief cause of national insecurity." - Celine's First Law
    4. Re:Mod parent up by msauve · · Score: 1

      Kilograms are not weight, they are mass.

      --
      "National Security is the chief cause of national insecurity." - Celine's First Law
    5. Re:Mod parent up by msauve · · Score: 2

      The internationally agreed time standard (TAI or UTC, which are the same, only different) is based on an ensemble of clocks throughout the world. The contribution from NIST (and USNO) is only a part of the realization.

      Because of this, actual time can only be known after the fact, because post-processing is needed.

      --
      "National Security is the chief cause of national insecurity." - Celine's First Law
    6. Re:Mod parent up by hyperfine+transition · · Score: 1

      In short, "counting vibrations" is a poor description of what's going on. In the case of a caesium fountain, what you're doing is driving a resonant transition in the atom with external microwaves. When the microwaves are tuned to the transition, the Cs atom changes its state, which can be detected. To make the microwaves, you usually start with something like a very good 5 MHz crystal oscillator and multiply it up (plus add an offset, also derived from the crystal) to get the transition frequency ( for the transition in Cs which defines what one second is, this is an exact frequency) . You then adjust the frequency of the crystal (this is done electrically) until you're centred on the resonance in the Cs atom. So then you can just electrically count the oscillations of the crystal and 5000000 of these will be your definition of what one second is.

  8. 300 million years by rossdee · · Score: 1

    " it will lose or gain only one second every 300 million years"

    Will it keep going for that long?

    Whats the point of time that accurate, when its going to be + or - an hoir every six months

    1. Re:300 million years by hcs_$reboot · · Score: 3, Insightful

      The point is not to get the actual date/time accurately, the point is to get the very accurate amount of time that elapsed between two events.

      --
      Slashdot, fix the reply notifications... You won't get away with it...
  9. Re:so the new clock is 3x as accurate as the old o by mythosaz · · Score: 3, Informative

    NIST has vastly more accurate clocks - so I don't see what the big deal is.

    http://www.nist.gov/pml/div688...

  10. Re:Ah another seemingly benign NIST approved stand by schneidafunk · · Score: 1

    And second is "first post" :)

    --
    Some people die at 25 and aren't buried until 75. -Benjamin Franklin
  11. Re:Ah another seemingly benign NIST approved stand by ChristopherMcGinnis · · Score: 1

    "Mister potatah head. Mister potatah head! Back doors are not secrets!" - Jim (War Games)

  12. All that accuracy... by grub · · Score: 2

    ... but they will still have to manually adjust for DST twice a year.

    --
    Trolling is a art,
  13. Re:Ah another seemingly benign NIST approved stand by Jeremiah+Cornelius · · Score: 4, Funny

    Is the new clock metric, or the old English units of measure?

    --
    "Flyin' in just a sweet place,
    Never been known to fail..."
  14. Re:so the new clock is 3x as accurate as the old o by Knee+Patch · · Score: 2

    Several of the sciences depend on extremely accurate timing. It's not a question of seconds lost over millions of years, but rather "how accurately can I time an event that is only a few nanoseconds long", or even better, "Exactly how far apart were these two events, even if the events are separated by hours, or days". It's misleading for the media to talk about timing in the way that they do, but apparently normal people's brains explode when someone says "nanosecond" or "parts per billion".

  15. gravitational time dialation by volvox_voxel · · Score: 4, Informative

    I met a guy that used to work at NIST that mentioned that their clocks are so sensitive, they can tell what floor the atomic clocks are on because of of the slightly different gravitational potential each clock experiences. I wonder what kind of resolution the can resolve. Can a very massive bolder throw off the clock a little? ..perhaps one day we will have to keep better track of the local gravitational potential well. It's possible to measure the gravitational constant with simple apparatus at home. Using two massive bodies in a torsion pendulum arrangement, you can estimate "big G" -- http://www.owlnet.rice.edu/~do...

    Here is an wikipedia article that mentions the phenomena with atomic clocks: http://en.wikipedia.org/wiki/G...

  16. Re:Ah another seemingly benign NIST approved stand by schneidafunk · · Score: 1

    I think you mean old Sumerians unit of measure.

    http://en.wikipedia.org/wiki/S...
      It originated with the ancient Sumerians in the 3rd millennium BC,

    --
    Some people die at 25 and aren't buried until 75. -Benjamin Franklin
  17. Re:Ah another seemingly benign NIST approved stand by PRMan · · Score: 1

    It's in the US. What do you think? Of course it's using that old "60 seconds in a minute, 60 minutes in an hour" bullcrap!

    --
    Peter predicted that you would "deliberately forget" creation 2000 years ago...
  18. Re:so the new clock is 3x as accurate as the old o by Anonymous Coward · · Score: 3, Informative

    The higher-accuracy clocks are not based on Cesium, which is a necessary basis for Standards Compliance. As I understand it, the F3 clock (from the article) is a "Cesium-fountain" atomic clock and is therefore suitable for use in standards-based calculations. The clock(s) referenced in that article, on the other hand, are Mercury and Aluminum based and therefore cannot be referenced according to SI standards.. The SI governing body would have to change their standard for the other clocks to be considered, but given how many things are based on the Standard, modifying it is a non-trivial exercise...

    -AC

  19. A man with one atomic clock knows what time it is. by EmagGeek · · Score: 5, Funny

    A man with two atomic clocks is never sure.

  20. Re:Kilograms are a weight by schneidafunk · · Score: 1

    You're right, my apologies.

    --
    Some people die at 25 and aren't buried until 75. -Benjamin Franklin
  21. Re:so the new clock is 3x as accurate as the old o by PRMan · · Score: 1

    I thought you were being funny, but it turns out you're totally serious. I didn't know the current clock was that accurate.

    --
    Peter predicted that you would "deliberately forget" creation 2000 years ago...
  22. Re:so the new clock is 3x as accurate as the old o by Anonymous Coward · · Score: 2, Funny

    Would someone tell me how this happened? We were the fucking vanguard of timekeeping industry in this country. The Naval Institute was the time to keep. Then the other guy came out with accuracy of 1 part per few billion. Were we scared? Hell, no. Because we hit back with a little thing called the Atomic fucking clock. That's A for both atomic and an aloe strip. For moisture. But you know what happened next? Shut up, I'm telling you what happened—the bastards went to went all nuclear on us. They've introduced accuracy of 1 second in 300 million years. Now we're standing around with our cocks in our hands, selling 1 part per few billion and a fucking strip. Accuracy or no, suddenly we're the chumps. Well, fuck it. We're going to 500 million.

    Sure, we could go to 400 million next, like the competition. That seems like the logical thing to do. After all, three worked out pretty well, and four is the next number after three. So let's play it safe. Why innovate when we can follow? Oh, I know why: Because we're a business, that's why!

    You think it's crazy? It is crazy. But I don't give a shit. From now on, we're the ones who have the edge in the time-keeping game. Are they the best a man can get? Fuck, no. Navy is the best a man can get.

    What part of this don't you understand? If accuracy of one second in 100 million years is good, and one in three million is better, obviously one in five million would make us the best fucking time keeping machine that ever existed. Comprende? We didn't claw our way to the top of the clock making game by clinging to the pendulum industry standard. We got here by taking chances. Well, one in 500 million is the biggest chance of all.

    Here's the report from Engineering. Someone put it in the bathroom: I want to wipe my ass with it. They don't tell me what to invent—I tell them. And I'm telling them to stick two hundred million years in there. I don't care how. Make the atoms so small they're invisible. Put some on the handle. I don't care if they have to cram the last 100 million years in perpendicular to the other four, just do it!

    You're taking the "safety" part of "nuclear safety" too literally, grandma. Cut the strings and soar. Let's hit it. Let's roll. This is our chance to make time keeping history. Let's dream big. All you have to do is say that one second in five hundred million years can happen, and it will happen. If you aren't on board, then fuck you. And if you're on the board, then fuck you and your father. Hey, if I'm the only one who'll take risks, I'm sure as hell happy to hog all the glory when the one second in 500 million years becomes the standard in the U.S. of "this is how tell time from now on" A.

    People said we couldn't go to three. It'll cost a fortune to manufacture, they said. Well, we did it. Now some egghead in a lab is screaming "Five's crazy?" Well, perhaps he'd be more comfortable in the labs at Casio, working on fucking electrics. Wrist watches, my white ass!

    Maybe I'm wrong. Maybe we should just ride in CERN's wake and make particle accelerators. Ha! Not on your fucking life! The day I shadow a penny-ante outfit like CERN is the day I leave the atomic clock game for good, and that won't happen until the day I die!

    The market? Listen, we make the market. All we have to do is put her out there with a little jingle. It's as easy as, "Hey, telling time with anything less than 0.000000% accuracy is like trying to tell time from vcr display after a power outage" Or "Sure you'll still be late, but now you know exactly how late"
    I know what you're thinking now: What'll people say? Mew mew mew. Oh, no, what will people say?! Grow the fuck up. When you're on top, people talk. That's the price you pay for being on top. Which we are, always have been, and forever shall be, Amen. 1 second / 500 million years - sweet Jesus in heaven.

    Stop. I just had a stroke of genius. Are you ready? Open your mouth, baby birds, cause Mama's about to drop you one sweet, fat nightcrawler. Here she comes: Put another ntp s

  23. will XP still work with this New Clock? by turkeydance · · Score: 1

    please make XP work. please.

  24. Wise Man Says by Greyfox · · Score: 1

    Man with one atomic clock knows what time it is, man with two isn't sure.

    --

    I'm trying to teach myself to set people on fire with my mind... Is it hot in here?

    1. Re:Wise Man Says by TheGratefulNet · · Score: 1

      man with 2 atomic clocks is a foolish man; the same money could be spent on a gps receiver that disciplines the atomic clock.

      (yes, I'm actually serious)

      --

      --
      "It is now safe to switch off your computer."
  25. Re:Ah another seemingly benign NIST approved stand by TheGratefulNet · · Score: 1

    this is a clock, with uncertainty at both the front and back. therefore, it could be a front-door for the NSA.

    and if its a quantum clock, it could be both (or neither) at the same time!

    --

    --
    "It is now safe to switch off your computer."
  26. Re:Kilograms are a weight by Ol+Olsoc · · Score: 2

    Kilograms are a MASS

    No, they are pretty neat actually.

    --
    The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
  27. in development for about a decade? by HtR · · Score: 1

    It's accurate to 1 second in 300 million years, and the development time is "about a decade"?
    I feel like my brain has whiplash reading about these differences in time precision.

    --
    Have you tried turning it off and on again?
  28. Have to remember... by hcs_$reboot · · Score: 1

    ...to adjust the clock on 300002014/04/03 17:36:54

    --
    Slashdot, fix the reply notifications... You won't get away with it...
  29. Re:Ah another seemingly benign NIST approved stand by Cryacin · · Score: 1

    I've always wondered at what point in time do atomic clocks become more accurate than time dilation differences as we move through the universe from one place on Earth to the other.

    --
    Science advances one funeral at a time- Max Planck
  30. Re:so the new clock is 3x as accurate as the old o by stox · · Score: 1

    http://youtu.be/K00rz73s_zU

    --
    "To those who are overly cautious, everything is impossible. "
  31. Re:so the new clock is 3x as accurate as the old o by bluefoxlucid · · Score: 1

    You wouldn't want your clock to be inaccurate. I mean what if you went into stasis for 18 months and came out 300 million years later?

    --
    Support my political activism on Patreon.
  32. laptop hp by laptopnhatlong · · Score: 1

    http://laptopnhatlong.vn/lapto...

  33. Re:Still waiting for the rice grain sized Atom Clo by RabidReindeer · · Score: 1

    ....drones to airdrop missiles or fast food on my front door.

    Hence the term "gut bombs".

  34. Can't trust that clock. by thatkid_2002 · · Score: 1

    Probably compromised by the NSA.

  35. Re:so the new clock is 3x as accurate as the old o by Yaur · · Score: 1

    http://www.theonion.com/articl...

  36. Re:Ah another seemingly benign NIST approved stand by Anonymous Coward · · Score: 2, Interesting

    Atomic clocks in the 70s could show dilation effects from travel on airplanes or in satellites. GPS satellites regularly have to deal with this. The most precise clocks these days (more precise than the ones in the story here) can measure time dilation effects from just stacking the clocks on top of each other due to change in altitude of less than a meter. But for the most part these effects don't matter in the big picture, as you can define time relative to a frame not moving with respect to Earth at a specific elevation.

  37. posterity by loshwomp · · Score: 2

    it will lose or gain only one second every 300 million years

    Can't they just leave a note to the future people to click it forward/back at the right time?

    If the clock in question supports 9-digit years, they could even set an alarm...

  38. Well... by quonsar · · Score: 1

    ...it's about time.

    --

    Sacred cows make the best burgers.

  39. Re:Ah another seemingly benign NIST approved stand by k8to · · Score: 1

    The Sumerians gave us the number "base-like" system that is used in time, but the actual units of hours and seconds that we use didn't come until much later. The Babylonians for example divided the day into 6 top-level units and then down from there.

    http://en.wikipedia.org/wiki/S...

    --
    -josh
  40. Three times more accurate by Arancaytar · · Score: 1

    This may seem redundant to you. But you'll change your tune in 100 million years when the old clock is already a second out of sync while the new one is still within 0.33s.

  41. Heh by Arancaytar · · Score: 1

    Well, the 300 million years is just an estimate and it could go either forward or backward. I guess they could build a yet more accurate clock to use as a reference... :P

  42. The sky is the ultimate clock, I think? by mmell · · Score: 1

    At least, every timekeeping instrument I've ever heard of is designed to measure fractions of the interval defined as a day/year/trip around the galactic center (at this point, I'm considering the calendar to be an extension of the clock).

  43. Tier II. by mmell · · Score: 1

    That is all.

  44. Finally... by uncqual · · Score: 1

    ...I won't be late for meetings anymore.

    --
    Why is there an "insightful" mod and why isn't it "-1"? If I wanted insight, I wouldn't be reading /.
  45. Just great. by fahrbot-bot · · Score: 1

    The institute will continue operating both clocks for now at its campus in Boulder, Colorado.

    A man with one atomic clock knows the time, a man with two is never sure - every 300 million years or so, sigh.

    --
    It must have been something you assimilated. . . .
  46. Re:Ah another seemingly benign NIST approved stand by Big+Hairy+Ian · · Score: 1

    I just wonder what the Prompt Zone (Blast Radius) will be when the alarm goes off

    --

    Build a Man a Fire, and He'll Be Warm for a Day. Set a Man on Fire, and He'll Be Warm for the Rest of His Life.

  47. And how do you start it? by allo · · Score: 1

    I guess its not easy to sync it with the existing ones. NTP will not do the job ;).

    1. Re:And how do you start it? by hyperfine+transition · · Score: 1

      You can sync it with existing clocks to an accuracy of perhaps 500 picoseconds using well-established techniques like GPS-carrier phase and Two-way Satellite Time-Transfer.

    2. Re:And how do you start it? by allo · · Score: 1

      hmm, and the new one with the new error is then the new reference? Not that it really matters ...

    3. Re:And how do you start it? by hyperfine+transition · · Score: 1

      Typically, there is no single clock that is "the reference". The international time standard, UTC, is an average of about 400 or so atomic clocks from all around the world. There are a number of caesium fountains currently contributing to UTC. Even in a single laboratory, where there a number of clocks, these clocks will usually be averaged and one clock then adjusted to keep to this average. There are various practical reasons for this. If you have a number of similar clocks, the average will have a more stable frequency than a single clock. Some clocks are better at very short averaging times, others better for the long term so you can make an average that takes this into account. State-of-the-art clocks seldom work continuously so you need something else as a flywheel between operating times.

      The main use for very good clocks is as frequency references, or to measure the time interval between two events (in which case any offset cancels out) rather than time of day references. Sub-nanosecond synchronisation of distributed systems is only used in some very specialised scientific applications like Very Long Baseline Interferometric telescopes.

    4. Re:And how do you start it? by allo · · Score: 1

      But isn't averaging even more unstable than syncing with one clock? And in any case, this one will be more precise than the average and every single other one.

  48. Time is an illusion by ITMagic · · Score: 1

    Lunchtime doubly so.

  49. 60HZ Reference by roarkarchitect · · Score: 1

    Just wondering how many people realize that the 60HZ line frequency is eventually tied to this standard ?

  50. Calibration? by tree_frog · · Score: 1

    Will they be bringing Johnny Marr in to calibrate it?

  51. no boulderites protesting "radioactive" clock? by peter303 · · Score: 1

    The NIST lab is just south of the UC Bouder campus. People in Boulder get worked up about progressive causes sometimes.

  52. Slashdot version by fulldecent · · Score: 1

    So... is there a technical explanation with diagrams that shows how this new clock works?

    --

    -- I was raised on the command line, bitch

  53. Re:Ah another seemingly benign NIST approved stand by TangoMargarine · · Score: 1

    metric time

    --
    Unity? Screw that: XFCE. Slashdot Beta? Screw that: SoylentNews. Australis? Screw that: Pale Moon. UX developers DIAF
  54. Re:Software upgrade by unixisc · · Score: 1

    Will time.nist.gov now map to this new clock, or still the old one?