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Technology Science

New Atomic Clock 1000 Times More Accurate 313

Posted by CowboyNeal
from the chronographs-and-tickers dept.
stevelinton writes "The UK National Physical Laboratory has a new atomic clock potentially 1000 times more accurate than current cesium clocks: to within 1 second in about 30 billion years! This could lead quite soon to a new definition of the second, and in a while to improved resolution in GPS successor systems. More interestingly, there are theories that some of the universe's fundamental dimensionless constants may have changed by a parts in a million over the last 10 billion years or so. These clocks are so accurate that they should be able to detect these changes over a year or two."
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New Atomic Clock 1000 Times More Accurate

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  • by grub (11606) <slashdot@grub.net> on Saturday November 20, 2004 @12:34PM (#10875215) Homepage Journal

    This could lead quite soon to a new definition of the second

    Now all we need is a13 year old to update the wikipedia entry.
    • Now all we need is a13 year old to update the wikipedia entry

      Hey! Wait a secon........never mind

    • Second Minute (Score:5, Informative)

      by zenzic (804840) on Saturday November 20, 2004 @01:20PM (#10875507)
      According to Silvanus Thompson in his famous (and awesome!)(c1910) calculus book the word second comes from the term "second minute".

      I thought that was a neat and strange word origin (if correct).

      to quote him...
      "When they came to require still smaller subdivisions of time, they divided each minute into 60 still smaller parts, which, in Queen Elizabeth's days, they called "second minutes" (i.e. small quantities of the second order of minuteness). Nowadays we call these small quantities of the second order of smallness "seconds"."

      • by kingkade (584184) on Saturday November 20, 2004 @01:25PM (#10875533)
        Thank you for the answer to a question no one asked.
      • Well, in greek "minute" is lepto, and second (in modern greek) is deutero (second) lepto, so that sort of makes sense...
        (although I'd guess the greek version is really from the old english one ).
      • Re:Second Minute (Score:3, Informative)

        by mattdm (1931)
        OED backs this up:

        a. F. seconde, ad. med.L. secunda, fem. of L. secundus SECOND a., used ellipt. for secunda minuta, lit. 'second minute', i.e. the result of the second operation of sexagesimal division; the result of the first such operation (now called 'minute' simply) being the 'first' or 'prime minute' or 'prime' (see PRIME n.2 2)
      • Re:Second Minute (Score:4, Informative)

        by Anonymous Coward on Saturday November 20, 2004 @04:38PM (#10876645)
        I guess while We're at it, Queen Elizabeth should be credited with the invention of the Time Machine as well.

        According to multiple sources (see Eli Maor, Trigonometric Delights, Princeton Press, etc):

        "The Greeks called the sixtieth part of a degree the "first part," the sixtieth part of that the "second part,"...

        In Latin the former was called pars minuta prima ("first small part") and the latter pars minuta secunda ("second small part"),
        from which came our minute and second."

        The actual subdivisions are Babylonian in origen, since they invented the concept of the 24hr day
        with sexagesimal units of time (hours) which were subdivided a SECOND time into 60 TINIER chunks (seconds).

        Notice also that most romance languages have words for this unit of time that not only predate Queen Elizabeth's birth, but the English language itself.
  • ...what if someone forgets to wind it?
  • Great! (Score:5, Funny)

    by nixdorf_ (161552) on Saturday November 20, 2004 @12:35PM (#10875233)
    My boss will now know with 1000x the accuracy exactly how late I am. Wonderful!
  • Having seen the atomic wrist watch linked fromthe article about the guy who recently made a chess set... I only consider this technology cool if you can wear it on your wrist!
    • Re:Wrist Watch? (Score:2, Informative)

      by TeaQuaffer (809857)
      The link of which you speek is here [leapsecond.com]

      My favorite quote is "Batteries are included (they last about 45 minutes but are rechargeable)."

    • I find radio-controlled clocks much more convinient. Not only are they as accurate as an atomic clock, but they also adjust automatically (and correctly) for daylight-savings.
      • Re:Wrist Watch? (Score:3, Interesting)

        by Detritus (11846)
        They are nowhere near as accurate as an atomic clock. Even with a lab grade radio clock, large amounts of error are introduced by the propagation delay of the radio signal, which isn't constant. Consumer grade radio clocks are useless for any serious applications. They use cheap quartz crystal oscillators and compensate for errors by resetting the clock once a day.
  • it even... (Score:2, Funny)

    by enrico_suave (179651)
    glows in the dark too!

    oh i'm kidding, c'mon =)

    e.
  • by Ckwop (707653) * <Simon.Johnson@gmail.com> on Saturday November 20, 2004 @12:39PM (#10875265) Homepage

    Great.. now I can measure measure how late the train is to an accuracy of a few attoseconds. hehe

    The great thing about getting more accurate timing is that it should allow you to measure distances with the same accuracy. I think that by shining two different coloured lasers against a mirror and measuring the beats in the interference pattern of the returned beam it should be possible to measure a metre very exactly.

    Anyone know if this is garbage or does more accurate time mean more accurate distance.

    Simon.

    • by MasterC (70492) <cmlburnett@gm[ ].com ['ail' in gap]> on Saturday November 20, 2004 @12:50PM (#10875333) Homepage
      The length of the meter is defined by time

      http://physics.nist.gov/cuu/Units/meter.html

      "The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second."

      So if you can measure time more accuractly then you can measure a meter more accurately.
    • by Mister Attack (95347) on Saturday November 20, 2004 @12:51PM (#10875340) Journal
      The trouble with measuring a meter this way is that it's tricky, to say the least, to know the frequency of a laser beam to high enough precision for this to be a useful measurement. You'd basically have to do exactly what these guys are doing -- cool some ions to within a few microkelvins of zero, use them as a frequency reference and lock a laser to them. Then you'd have to do it again with a different frequency. Then you'd have to actually measure the intensity of the standing wave to high enough resolution that you could get a reasonable measurement. So basically, don't hold your breath.

      Much more reasonable is to keep the current definition of the meter, which is the distance that light travels in 1/299,792,458 second in a vacuum. Then your better clock gives you a more accurate length standard without all the fuss.
    • by bobdotorg (598873) on Saturday November 20, 2004 @12:57PM (#10875366)
      it should be possible to measure a metre very exactly.

      Ah - but I suspect that measurement of what comprises six inches will be as imprecise and inaccurate as it's always been.
  • Why do this? (Score:2, Interesting)

    by zerman (832210)
    I don't mean to be offensive, but is there any real point to this? How much accurate does the clock really have to be? What is the point of having a clock that is this accurate? We pour millions of dollars into this type of thing. So what? Even if we did need the accuracy (which we don't) we would never have it because the accuracy bottleneck would always be transporting the signal to wherever it's needed. Can anyone think of one good example where this clock serves any real purpose, and the old cesium one
    • Re:Why do this? (Score:4, Informative)

      by Lisandro (799651) on Saturday November 20, 2004 @12:43PM (#10875294)
      It won't be of any use to the regular Joe. But there's a lot of scientific experiments that rely on accurate time measurements, notably those involving relativistic effects.
    • Well, if it is accurate enough to detect minute changes in physical constants, then it will be worth it, as it will give us better understanding of the universe around us.

      And it allows the UKians to brag, and also detect the end of a soccer match with much more accuracy.
    • I don't mean to be offensive, but is there any real point to this?
      "This could lead quite soon to a new definition of the second, and in a while to improved resolution in GPS successor systems. More interestingly, there are theories that some of the universe's fundamental dimensionless constants may have changed by a parts in a million over the last 10 billion years or so. These clocks are so accurate that they should be able to detect these changes over a year or two."
    • Re:Why do this? (Score:5, Informative)

      by stevelinton (4044) <sal@dcs.st-and.ac.uk> on Saturday November 20, 2004 @12:47PM (#10875318) Homepage
      The accuracy of caesium clocks is one of the factors limiting GPS accuracy to a meter or so. These clocks could get that down to a millimeter allowing, for instance, GPS based automated guidance for trucks and automated landing for planes.

      There are also applications in scientific research -- I mentioned detecting changes in fundmental constants in the story, it might also help allow very long baseline interferometry (where two radio telescopes thousands of miles apart obtain the same resolution as one telescope thousands of miles wide) at higher frequencies, pushing into the long IR.
      • Re:Why do this? (Score:5, Interesting)

        by maeka (518272) on Saturday November 20, 2004 @01:08PM (#10875432) Journal
        The accuracy of the clocks is a small factor in real-time GPS accuracy.

        Ionospheric delay plays a much larger role. Survey-grade receivers use both the L1 and the L2 bands in an attempt to better model this delay. Ionospheric delay is frequency-dependent and impacts on the L1 and L2 signals by a differing amounts.

        Multipath plays a role also, not as big as the ionosphere, but still larger than the accuracy of the clocks on the GPS satellites.

      • I find errors in the datasets larger than the GPS positioning error.

        computer guided trucks, the horrible idea consideringthe horrible accuracy of the gurrent GPS dataset's available. no not the low grade Delorme maps for US Census data... I'm talking the high priced stuff from the company navtek that claims the highest accuracy possible. (yet missing most data, having roads where they do not exist and having the position of an entire highway off by over 500 meters.

        if we cant get good data to begin with,
      • I thought atomic clocks were much larger.

        The Hewlett Packard 5071A mentioned above surprised me a lot.

        Can anyone give a rundown of how they work?
      • The phase centre of the receiving antennae is not the same for all directions. Even in the absense of ionosphere and timing errors, one could never be sure (unless the antenna rotation was known).

        Z
        • The phase centre of the receiving antennae is not the same for all directions. Even in the absense of ionosphere and timing errors, one could never be sure (unless the antenna rotation was known).

          To the extent this is a problem it can be modeled and accounted for. It's not that big of a problem.

          It's not that big of a problem (and easy to account for) because the phase center shifts largely as a function of the elevation and azimuth of the satellite signal.

          The Trimble Zephyr Geodetic antennas I often

    • "A second highly-monochromatic red laser (674 nm) is then aimed at the cold ion, and tuned to two very precisely defined energy states in the cold ion. Once the laser is locked on to this precise energy or frequency interval it becomes very stable."

      ASIDE: Strontium give the nice red you see in fireworks.

      Physical constants are defined in terms of time. We only know that they are constants so far as we can measure the passage of time. Our model of the universe is based on constancy. With a better clock we
    • Re:Why do this? (Score:5, Interesting)

      by Misanthropy (31291) on Saturday November 20, 2004 @01:15PM (#10875481)
      I was thinking the same thing until I actually read the article.

      An answer from the article that affects everyone and not just super geek physicists:

      Navigation on earth - based on a cluster of orbiting satellites - is limited by the accuracy of the atomic clock on each satellite. A series of calculations can get millimetre accuracy on the position of a stationary object, but for moving objects like cars and planes the accuracy is no better than a few metres. Only by making faster measurements can this accuracy be improved, something enabled by a more accurate definition of the second.
      ...
      "That is why GPS is not yet good enough to land a passenger aircraft on its own," Prof Gill says.


      Pretty cool stuff.
      • Navigation on earth - based on a cluster of orbiting satellites - is limited by the accuracy of the atomic clock on each satellite. A series of calculations can get millimetre accuracy on the position of a stationary object, but for moving objects like cars and planes the accuracy is no better than a few metres. Only by making faster measurements can this accuracy be improved, something enabled by a more accurate definition of the second.

        This is where the article is plane (Haha!) wrong.
        The limiting fact

    • Re:Why do this? (Score:5, Interesting)

      by Tony-A (29931) on Saturday November 20, 2004 @02:43PM (#10875929)
      Can anyone think of one good example where this clock serves any real purpose

      Predicting earthquakes and volcanos.
      Finding oil, gas, mineral deposits.
      Hardly automatic, but attaining extreme accuracy cheaply can only help.

      With a few high precision clocks broadcasting, it is possible to triangulate position precisely and hence the delay time. Precision in timing translates into precision in distance. If stuff is moving inches per decade or century, it would be interesting to know exactly how that movement is accomplished.
  • upgrade (Score:2, Interesting)

    by Barsema (106323)
    I guess this guy [leapsecond.com] will need an upgrade.
  • More interestingly, there are theories that some of the universe's fundamental dimensionless constants may have changed by a parts in a million over the last 10 billion years or so. These clocks are so accurate that they should be able to detect these changes over a year or two.

    Exactly how long will it take to detect these changes?
  • by cortana (588495) <{sam} {at} {robots.org.uk}> on Saturday November 20, 2004 @12:48PM (#10875324) Homepage
    Call me back when there's a portable version [leapsecond.com] available.
    • by deglr6328 (150198)
      This brings up an interesting point dosent it? How can a clock accurate to one in 10^15 or one second in 30 billion years ever be truly useful to that accuracy? Wouldn't simply walking the thing down the hall to the next lab introduce unacceptable error in the clock due to the time dilation involved?
  • Why go any further (Score:3, Interesting)

    by suso (153703) on Saturday November 20, 2004 @12:49PM (#10875327) Homepage Journal
    1 second every 30 billion years? That's more than twice as long as the age of the universe. So why then would atomic clock developers need to go any further?
    • by stevelinton (4044) <sal@dcs.st-and.ac.uk> on Saturday November 20, 2004 @12:52PM (#10875341) Homepage
      Because they're interested in deviations of much less than a second.
      • Really? Because when they say "loses one second every billion years", it sounds like they are using it to keep time.

        For what its worth, I understand tht atomic clocks are more used for minute time measurement than keeping time. But I wish they would say something like "accurate to a nano-second" or whatever.
        • by ThJ (641955)
          Accuracy and precision are not the same, as outlined in other replies to this article. The less drift you have over time, the more accurate it is. The higher number of ticks you have pr second, the more precise it is. It would be interesting to know the number of ticks/second these things can do, though...
      • by gtkuhn (823989)
        But this won't help them find deviations in physical constants even if they "find them". Unless we build dozens or hundreds of these clocks, we'll never know if the universe is changing or if there is a manufacturing defect in the clock.
        • Unless we build dozens or hundreds of these clocks, we'll never know if the universe is changing or if there is a manufacturing defect in the clock.

          Well...yes?

          But they had to build the first one somewhere, and develop the technology before they do mass production, right? When Edison built the first light bulb, did people say, "Gee, that's cool Tom, but it's of no use to us. You've only got one."

          If you're looking for subtle physical effects, you'd probably have to have a couple of these clocks in a g

        • by arminw (717974)
          ...we'll never know if the universe is changing....

          If the universe IS changing, we'll never know from these clocks since they would also be subject to change. The atomic forces that control the vibrations of the atoms that govern these clocks also could change, and if they do, all the clocks they are based on would change and we would never detect any differences.

          If the basic parameters of space-time change, the properties of the atoms within the space-time would also have to change. All equations govern
          • by Council (514577)
            If the universe IS changing, we'll never know from these clocks since they would also be subject to change.

            Understandable first reaction but not at all true.

            For one, that's saying that we can't measure changes in fundamental constants AT ALL, which isn't true. We could find that our value for G has changed over time in the fifth decimal place.

            All these researchers are syaing is that we can now look for changes three decimal places further than we used to.

            (Regarding the idea of measuring the change of
    • by metlin (258108) *
      Because you need precise measurements for things other than needing to know what the time is.

      And these clocks are not just used as solar clocks, they are calibrated to be sidereal clocks too - to know the movement of the stars and the like.

      Imagine you are conducting a particle collision experiment in a tunnel - the particles are almost travelling at the speed of light, and they'd cover the distance of your tunnel almost instantaneously. You would need to measure this as precisely as you can. The more this
    • Hey, when the goal is making something easier for lazy people to use, there's NO amount of effort that will be spared in reaching that goal! It's the American way. :) Looks like those UK physicists are learning from the best...
  • by melted (227442) on Saturday November 20, 2004 @12:51PM (#10875336) Homepage
    of clocks: "I see no progress in this industry. These clocks are no faster than the ones they made a hundred years ago."
  • I understand that in some types of backbone network connections, a pair of Atomic Clocks is synchronized, then one is sent to each end of the connection.

    Will it be possible to run these connections at a higher speed with more accurate clocks?
  • Not really new (Score:5, Informative)

    by Dolphinzilla (199489) on Saturday November 20, 2004 @12:56PM (#10875362) Journal
    trapped ion frequency standards are nothing new, NIST made one years ago, the only difference is that NPL uses Strontium instead of Mercury. While it appears to be more accurate than the NIST one, trapped ion standards are not very practical to build or run for everyday use and its not a primary frequency standard, since the definition of the second is in terms of Cesium resonance, only Cesium clocks are primary frequency standards.
    • They claim that this setup is simpler than the NIST one, as well as 3 times more accurate.

      It also seems to be understood that once some sort of optical resonance technique becomes established, the second will be redefined in terms of it.

      Steve
  • by ZoneGray (168419) on Saturday November 20, 2004 @12:57PM (#10875364) Homepage
    That's all well and good, but I'll bet it still flashes "12:00-12:00-12:00" after the power goes off.
  • not really. what a difference a year and a half makes [slashdot.org]. someone even mentioned 1 in 30bn in the comments
    • Yeah, this article doesn't even have the same /. charm, I mean the submitter didn't even spell lose loose, jeez...people these days....
  • by TeaQuaffer (809857) on Saturday November 20, 2004 @01:00PM (#10875380)
    There is a little blip by Chris Carilli [physicsweb.org] about changes in constants. [SIC] and more detailed article here [physicsweb.org].

    Does anyone know more about this?

  • Remember folks, turn your fine-structure constant [physlink.com] ahead tonight before going to bed.
  • now this is a cool clock - it is mechanical and keeps time for 10,000 years ! http://www.kk.org/tools/page6-9.pdf [kk.org]
  • Bad reporting (Score:5, Informative)

    by fatphil (181876) on Saturday November 20, 2004 @01:12PM (#10875461) Homepage
    Slashdot's error -
    It's not 1000 times more accurate, it's 3 times more accurate (than the NIST's mercury ion resonator). The figure of 1000 is what they think the technology in the future, but that's purely hypothetical.

    NPL's errors -
    Bombarding an ion with a blue laser in order to cool it is _in_no_way_ similar to firing a beam of light at a mirror-ball. Mirror balls do not get cooler when you fire beams of light at them. Explanations that use inappropriate analogies are as useful as wearing tie-died lab-coats in night-clubs.

    If "one part in 10^18" is "nearly a thousand times more accurate than the best clocks of today", then today's best clocks must be accurate to 1 part in 10^15. Therefore this new clock, being "three times more accurate than the Americans", "3.4 parts in 10^15", cannot be the be the best clock of today. Either that or someone in NPL can't do simple maths.

    FP.
  • How do they know it's more accurate than cesium clocks? You need to compare this new clock to something else in order to tell whether it's more accurate. But how do they know this clock is more accurate, if they don't have something which is already 100.0% accurate?
    • What they really mean is more stable. If you compare a bunch of cesium clocks, or compare one cesium clock now with its behaviour at a different time (having bounced the signal off the moon or something) you get a random variation of (with the very best cesium clocks) about 1 part in 10^15. With these clocks, they expect to be able to get this variation down to 1 in 10^18 over the next few years.
    • Re:How do they know? (Score:3, Informative)

      by Detritus (11846)
      Hydrogen masers have better short-term stability than cesium frequency standards, so one can compare the two and measure the short-term variation in the frequency of the cesium standard.

      Clocks can also be run in groups. With some mathematics, the group can produce a result that is more accurate than a single clock.

      If you have a detailed knowledge of the physics involved in the operation of a clock, the possible sources of error can be modeled and predicted.

  • More interestingly, there are theories that some of the universe's fundamental dimensionless constants may have changed by a parts in a million over the last 10 billion years or so.

    PI IS EXACTLY THREE!
    -Prof. Frink

  • Awesome (Score:5, Funny)

    by roman_mir (125474) on Saturday November 20, 2004 @01:30PM (#10875552) Homepage Journal
    But the real question is can MS make a download status bar that is 1000 times more precise and does not go from 2 minutes to 20, then to 4 minutes, then to 5 minutes etc. Or this invention does not affect a standard Microsoft Millisecond (which I believe is a random function?)

  • Precisely? (Score:2, Insightful)

    by starglider29a (719559)
    I'm relativistically certain that when these articles and replies use the word "accurate", they really want to be saying "precise." Right?

    I mean, 'what time is it?' to the Universe? What time WAS it 'when time began'? Was there a 'countdown to the beginning of time?' And in which Universal Time Zone are we? Are we on "Universal Light Matter Savings Time?" Was Heinlein correct? IS THERE Time Enough for Love?
  • by adeyadey (678765) on Saturday November 20, 2004 @02:16PM (#10875806) Journal
    ..in my bedroom. It has stopped, and shows *exactly* the right time twice a day.

    This "accurate" clock you describe is only exactly right every few billion years..
  • fit on your wrist [cnn.com]?

    If not, I don't want to hear about it.

  • by WasterDave (20047) <davep&zedkep,com> on Saturday November 20, 2004 @04:12PM (#10876486)
    This has been bugging me for years. There's this spurious "atomic clocks are accurate to 1 second within a million years" thing - so how the hell to you measure it? And if you've got a more accurate way of measuring time, why not just use *that* as the clock.

    I know there's an answer, please enlighten.

    Cheers,
    Dave

    • Sorry for all the posts: I now really hate the "HTML formatted" box.

      The standard press description is a little confusing. A good way to think about the subject is that atomic clocks are extremely good frequency standards, which incidentally makes them good time standards as well (if I have a pendulum that oscillates once per second, I can measure time by counting the number of oscillations).

      The idea behind all atomic clocks is that atoms are very picky about the kinds of light they absorb and emit (that'

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