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Faulty Cable To Blame For Superluminal Neutrino Results 414

Posted by samzenpus
from the not-so-fast dept.
smolloy writes "It would appear that the hotly debated faster-than-light neutrino observation at CERN is the result of a fault in the connection between a GPS unit and a computer. This connection was used to correct for time delays in the neutrino flight, and after fixing the correction the researchers have found that the time discrepancy appears to have vanished."
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Faulty Cable To Blame For Superluminal Neutrino Results

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  • by Fluffeh (1273756) on Wednesday February 22, 2012 @06:20PM (#39130535)

    I am glad they went through the proper process of verifying all the hardware and have gotten to the bottom of this little fiasco - but wow, they have to be biting their lips in frustration.

    I also expect a cable manufacturer is likely to be getting a strongly worded email in the near future.

    • by c0lo (1497653) on Wednesday February 22, 2012 @06:27PM (#39130639)

      I am glad they went through the proper process of verifying all the hardware and have gotten to the bottom of this little fiasco - but wow, they have to be biting their lips in frustration.

      Why is this a fiasco? After all they discovered a pretty cheap way for FTL - just use defective cables!

    • by Lumpy (12016) on Wednesday February 22, 2012 @06:42PM (#39130819) Homepage

      "I also expect a cable manufacturer is likely to be getting a strongly worded email in the near future."

      Not really, Monoprice does not really care if the customer is doing science with their low price cables.

    • by gstrickler (920733) on Wednesday February 22, 2012 @06:44PM (#39130831)

      The cable transmitted the signal 60ns faster than the time used in their compensation. I wouldn't call that defective.

      Either the cable is shorter than they thought, or it's propagation factor is higher than specified, or they simply used the wrong number in their original calculations.

      Way too early to blame anything on the cable manufacturer.

      • by msheekhah (903443)
        The cable wasn't properly secured. It wasn't defective.
      • by ackthpt (218170)

        The cable transmitted the signal 60ns faster than the time used in their compensation. I wouldn't call that defective.

        Either the cable is shorter than they thought, or it's propagation factor is higher than specified, or they simply used the wrong number in their original calculations.

        Way too early to blame anything on the cable manufacturer.

        What's tuggin away at my trouserleg of concern is: How many other experients, with this cable in place, turned out as expected?

        Bit of a poser, that one.

        • by tjohns (657821)

          What's tuggin away at my trouserleg of concern is: How many other experients, with this cable in place, turned out as expected?

          Bit of a poser, that one.

          Likely none.

          My understanding is that the GPS setup was designed specifically for this experiment. Most experiments conducted at the LHC (or Gran Sasso) would be done entirely on-site and therefore don't need a super-accurate global time source.

      • by NEDHead (1651195) on Wednesday February 22, 2012 @07:25PM (#39131271)

        even if the propagation was at the speed of light through the cable, it would mean about a 60 length discrepancy. Unlikely to be missed

    • by flappinbooger (574405) on Wednesday February 22, 2012 @10:49PM (#39132745) Homepage
      I've made mistakes and I've had bad cables, but man, I can't imagine dealing with something where the whole world is hearing about it....
  • Headline is wrong (Score:5, Insightful)

    by Omnifarious (11933) * <eric-slashNO@SPAMomnifarious.org> on Wednesday February 22, 2012 @06:20PM (#39130539) Homepage Journal

    It should read "Faulty Cable Most Likely To Blame For Superluminal Neutrino Results". They haven't proved anything yet. They just found a problem that's very suggestive and they need to re-run the experiment after fixing/accounting for the problem.

    • Face it (Score:2, Interesting)

      by Anonymous Coward

      We will never get off this rock. Interstellar travel is impossible, and always will be.

      We will all grow old and die here, and that's it.

      • Re:Face it (Score:5, Funny)

        by Anonymous Coward on Wednesday February 22, 2012 @06:36PM (#39130727)

        We will never get off this rock. Interstellar travel is impossible, and always will be.

        We will all grow old and die here, and that's it.

        You must be a real blast at parties.

      • Re: (Score:3, Insightful)

        by Surt (22457)

        Exceeding lightspeed is in no way required for interstellar travel. The problems of interstellar travel are, in fact, quite tractable.
        We (in the sense of you and me, specifically) will indeed never get off this rock. But our grandchildren might.

        • Re:Face it (Score:4, Interesting)

          by Lumpy (12016) on Wednesday February 22, 2012 @06:46PM (#39130835) Homepage

          "We (in the sense of you and me, specifically) will indeed never get off this rock. But our grandchildren might."

          My grandfather said those exact words.

          I'm betting you are as wrong as he was

          • Re:Face it (Score:4, Interesting)

            by Samantha Wright (1324923) on Wednesday February 22, 2012 @07:02PM (#39131013) Homepage Journal

            They're really more like metaphorical grandchildren. Sort of like "the World of Tomorrow"—it's not actually coming within 24 hours, but it will eventually. Now extrapolate that time measurement—the duration between when flying cars were first promised and when they finally appeared and achieved widespread adoption, say. If we assume it takes a minimum of twelve years for someone to go from birth to reproductive functionality (to some this is a little harsh, I know, but that's biology for you; just remember that, to others drinking certain Monsanto-enhanced milk, it's three years excessive) then we need at least twenty-four years to get grandchildren.

            So after eight thousand, seven hundred and sixty-six "tomorrows", we'll finally get off this rock.

            Given that the amount of time involved in a "tomorrow" is already a hundred years and steadily growing, we will probably be a space-faring civilization within the next million years.

            Not bad, when you think about it from a solar heat death perspective.

            • Re:Face it (Score:5, Insightful)

              by kermidge (2221646) on Wednesday February 22, 2012 @08:05PM (#39131641) Journal

              I recall my grandfathers. Both grew up on farms. Tilling was done with a plow pulled by draft animal. Lighting was by candle, kerosene lantern, or acetylene lamp. Water came via a bucket or hand pump from a well. One lived to see Armstrong and Aldrin walk on the Moon.

              Once we talked about a few things, some prosaic, some not. His basic position was that after all the things which in his life had been generally considered impossible and which later came to pass, it seemed to him to be presumptuous to rule things in or out.

              We've seen that Life exists where it can. I suspect that, whether in a form we may readily recognize or no, it may do so elsewhere. Perhaps we may, as well.

              Meanwhile, check connections. [grin]

              • Re:Face it (Score:4, Interesting)

                by Samantha Wright (1324923) on Wednesday February 22, 2012 @08:43PM (#39131973) Homepage Journal
                Of course we may—if all of humanity's resources were reallocated appropriately, we could have a well-to-do colony on Mars by now. Nothing in 2001 but the monoliths were grossly impossible; not even the date. The issue, which I tried to hint at in my post, is that most people don't dream of a better tomorrow. They dream of retiring to neat little homes and having the simple, manageable lives that our ancestors were hard-wired for. They want this [youtube.com]. And in between that and the stars, you have the layers upon layers of half-committal riff-raff; the money-gatherers and the rent-seekers who eternally race to build ant hills, wilfully and perpetually ignorant of their endeavours' futility. Kermidge, it very well may take us eight hundred thousand years to get into space for good; there are still not enough dreamers amongst us. We may have come along way in an amazingly short time, but we have rarely gone in the direction we were hoping. For that, we need to get over ourselves.
                • If what we do on Earth is build ant hills then what we would do on Mars would be ant hills too. Really expensive ant hills, but ant hills nonetheless.

        • Re:Face it (Score:4, Insightful)

          by gutnor (872759) on Wednesday February 22, 2012 @07:19PM (#39131199)

          Without faster than light you can get off this rock but you cannot support a civilisation. The closest star is already 4 light years away. Even at light speed, a return trip would take 8 years and that is already too much to maintain the relationship required for a civilisation - after a few generations, there will be nothing in common between the 2 worlds.

          • Apparent travel time if you go as photons is zero. Why send your atoms if you can send a description of your atoms? It's way more efficient that way. If you have already uploaded your mind to software, then the atoms are irrelevant, just occupy an appropriate robot body as needed.

            Besides, why can't you have intermediate stations in the Oort clouds or on rogue planets between stars? Interstellar space is far from empty by the latest thinking.

      • Re:Face it (Score:5, Interesting)

        by DanielRavenNest (107550) on Wednesday February 22, 2012 @08:54PM (#39132049)

        Thus you join a long line of people who said something is impossible, and were wrong.

        First, technically 5 man-made objects are on their way to interstellar space (Pioneer 10 & 11, Voyager 1 & 2, and New Horizons). They are slow, but leaving the Solar System nonetheless.

        Second, we have nuclear power. That is sufficient for "generation ships". Those travel only a small fraction of the speed of light, but with a nuclear power source you can keep a community going for generations until you arrive.

        Third, nanotechnology has the promise of travel to other stars at zero effective time delay to the traveller, and speed of light actual speed. Here is how: you scan a person at atomic resolution. Then you send a *description* of their body, atom for atom via powerful laser. At the destination, a nanotech assembler builds a copy atom for atom. There are large practical challenges to doing this, but no new physics required. Sending photons describing which atoms takes about a million times less energy than sending the atoms themselves at near light-speed, so this method is vastly more efficient, and would be the first choice over antimatter or very big solar powered lasers. Those are the only ways to get more energy/kg in the vehicle than fusion that we know of, which is what you need to get substantial fraction of speed of light.

        Fourth, perhaps cryostasis or life extension via cloning stem cells or some such will get developed, so even with a slow starship you can still get there.

        Fifth, there is plenty to do expanding into the Solar System, including the Oort Cloud, before worrying about interstellar trips. How about we figure out how to mine the Near Earth asteroids first? They are closer in energy terms than the Moon, and it's mission energy which costs you in space, not physical distance. We can practice by mining space junk in orbit, which also helps fix the orbital debris problem.

    • by ackthpt (218170) on Wednesday February 22, 2012 @06:30PM (#39130669) Homepage Journal

      It should read "Faulty Cable Most Likely To Blame For Superluminal Neutrino Results". They haven't proved anything yet. They just found a problem that's very suggestive and they need to re-run the experiment after fixing/accounting for the problem.

      Part of the Scientific Method* is the ability to repeat your results. When they state "the time discrepancy appears to have vanished" it would seem they are unable to reproduce the prior results.

      *This Post Not Approved By Rick Santorum For President or Heartland Institute

      • Re:Headline is wrong (Score:4, Informative)

        by ceoyoyo (59147) on Wednesday February 22, 2012 @06:33PM (#39130695)

        Don't believe everything you read in a summary. They found a loose cable that could have caused the delay. They're checking now. Despite the slashdot headline and summary, nothing has been confirmed.

        • by ackthpt (218170)

          Don't believe everything you read in a summary. They found a loose cable that could have caused the delay. They're checking now. Despite the slashdot headline and summary, nothing has been confirmed.

          There's still hope for my Superluminal Neutrino-powered Spaceship to the hot, steamy planet of Airline Stewardesses?

          This is a great day for SCIENCE

          • If you have ever flown Continental Airlines you would rethink your destination...
          • by vlm (69642)

            I have to think about this for a second, but I'd assume the neutrinos had a Very accurately measured speed. So maybe the story isn't that the neutrinos go supraluminal, its that fiber optic cable at CERN has a slightly negative velocity factor...

            Now you'd think people have measured the length of fiber with a OTDR before (god knows I have enough time) but maybe there is something weird about CERNs fibre, like they had to wrap the slack somewhere and they had a 10 tesla superconductive magnet laying around o

        • by msobkow (48369)

          Don't cling to false hopes when every subsequent test by the same facility and elsewhere has failed to repeat the results.

          It was a bad cable.

          Period.

          No FTL yet.

          • by pavon (30274) on Wednesday February 22, 2012 @06:56PM (#39130955)

            The results could be wrong, but for another reason. When trouble shooting you usually think of dozens of potential way things could have cause the problem before tracking down the actual root cause. Jumping to conclusions simply gets everyone's hopes up that the mystery has been solved.

            It was a bad cable.
            Period.

            So if you were in charge, you would just stop looking for the root cause which may go on to taint other results at CERN for years to come? Nothing is certain until it has been confirmed.

          • No FTL ever: it is a logical impossibilty. There was, however, hope of interesting new physics.

      • by Fned (43219)

        When they state "the time discrepancy appears to have vanished" it would seem they are unable to reproduce the prior results.

        Who is "they"? I saw no such statement in the article.

        After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis.

        Sounds to me like they haven't actually reached the point of trying to reproduce the results yet, they just found a discrepency that very closely matches the apparently aberrant prior results.

        • Do they really need to re-run the experiment to conclude the cable is to blame? If you measure something with a ruler, find out it's Mmm long, then realise your ruler is out by Nmm, it's quite easy to deduce that the thing is actually (M+/-N)mm long, without needing to re-meausure. Of course, it can be useful to check it with a new ruler, particularly when it's quite an important measurement.

          Additionally or alternatively, a 60ns discrepancy in the cable transmission stuff doesn't change their actual measure

    • by smolloy (1250188)
      Yeah, about two seconds after submitting this story, I realised that I forgot to put a question mark at the end of the title as I had originally intended :(

      "Faulty Cable to Blame for Superluminal Neutrino Results?" would have been better, right?

      But I was a little more accurate with the summary I think.

  • This isn't definite (Score:5, Informative)

    by JoshuaZ (1134087) on Wednesday February 22, 2012 @06:20PM (#39130543) Homepage
    There's no definite statement from OPERA or CERN yet. Right now this is just a rumor. This also is definitely not the first suggested explanation. Let's wait and see.
    • by ananyo (2519492) on Wednesday February 22, 2012 @07:44PM (#39131449)
      It's more than a rumour, as this later report from Nature [slashdot.org] makes clear. There is an OPERA statement circulating today that suggests two potential problems with the set-up. One is the one reported here - the cable issue - the second is a problem with "the experiment’s pioneering use of Global Positioning System (GPS) signals to synchronize atomic clocks at each end of its neutrino beam". But you're right - they haven't made a public statement yet nor been able to quantify yet the contribution of each to the potential error. It doesn't look good for them though.
  • by bugs2squash (1132591) on Wednesday February 22, 2012 @06:22PM (#39130563)
    By my watch...
  • by Lev13than (581686) on Wednesday February 22, 2012 @06:22PM (#39130567) Homepage

    Did they remember to plug it in with the direction marks [amazon.com] pointing to the computer?

    • by ackthpt (218170)

      Did they remember to plug it in with the direction marks [amazon.com] pointing to the computer?

      Pretty sure they didn't buy their cables from Denon or through Amazon ... which would likely be good enough for us, but when you are building race tracks for atomic particles you generally buy them, out of necessity of the appearance of the project, from the guy who runs the $600 toilet seat store.

  • by Anonymous Coward on Wednesday February 22, 2012 @06:23PM (#39130575)

    A neutrino walks into a bar. The bartender says, "We still don't serve neutrinos here".

  • Science isn't broken after all! Or at least, thousands of experiments are still fundamentally "correct" to the best of our current scientific knowledge.

    (note however that they still need to re-do the neutrino test, according to the last sentence of TFA; at the moment they have merely found out that "data" sent over the fiber-optic cable arrives 60ns earlier then assumed)
    • by Hentes (2461350)

      On the other hand, we still can't exceed the speed of light.

    • by vlm (69642)

      at the moment they have merely found out that "data" sent over the fiber-optic cable arrives 60ns earlier then assumed

      How does that happen? I've worked at fiber using telecom companies since 96 (customer and provider sites) and I've never heard of a loose cable causing 60 ns of constant delay. Random jitter as the connector bounces around? OK yeah. Intermittent loss? OK yeah.

      You can trivially make a fiber "60 ns longer" but thats quite a length of extra fiber, not a tiny fraction of an inch.

      My guess is someone thought they were purchasing a X yard long fiber cable, but the helpful installers put in a X meter long fibe

      • Re:Hooray! (Score:5, Funny)

        by ackthpt (218170) on Wednesday February 22, 2012 @06:50PM (#39130899) Homepage Journal

        at the moment they have merely found out that "data" sent over the fiber-optic cable arrives 60ns earlier then assumed

        How does that happen? I've worked at fiber using telecom companies since 96 (customer and provider sites) and I've never heard of a loose cable causing 60 ns of constant delay. Random jitter as the connector bounces around? OK yeah. Intermittent loss? OK yeah.

        You can trivially make a fiber "60 ns longer" but thats quite a length of extra fiber, not a tiny fraction of an inch.

        My guess is someone thought they were purchasing a X yard long fiber cable, but the helpful installers put in a X meter long fiber without telling anyone, and the stereotypical telecom BS about loose connectors is the coverup for the situation. Or the gear is buggy, it stopped being buggy, and all the tech did was tighten the connectors, so "it must have been the connector". Uh huh, yeah, heard that one before.

        A television repairman is condemned to Hell for his practices of deceiving and overcharging customers. On his orientation tour of the netherworld he is led past people boiling in pits of lava, having their organs pecked out by beasts and others being flayed, over and over. Thus his fear is great as he is taken down a cavern to his own assignment of eternal doom. A demon shows him to a door, which he opens to find leads to a seemingly endless cavern piled high with television sets, DVD players, cable decoders, etc. "You must fix each and every one of them", proclaims the demon. The repairman relaxes and says, "Well, that doesn't seem so bad after all." "Ah," replies the demon, "but every one of them has an intermittent problem."

      • The cable was connected between the GPS time device and a computer. It's a secondary cable, not the primary experiment cable. I'm assuming the connection was not working so the computer was not being synchronized correctly and therefore mis-calculating results.
      • Maybe an impedance mismatch at the end(s) of the cable caused the biggest part of the signal to reflect back and forth a couple of times, over the entire length of the cable?

        60ns delay is 18m of cable.
        Or 6m of cable in which the signal bounces back and forth once.

        ADC GPS
        ADC ----- GPS

        • Maybe an impedance mismatch at the end(s) of the cable caused the biggest part of the signal to reflect back and forth a couple of times, over the entire length of the cable?

          60ns delay is 18m of cable.
          Or 6m of cable in which the signal bounces back and forth once.

          ADC <----- GPS
          ADC -----> GPS
          ADC <----- GPS
    • by sycodon (149926)

      Science wasn't broken before. In fact, had these results been replicated, it would have been a triumph of science.

    • they still need to re-do the neutrino test, according to the last sentence of TFA; at the moment they have merely found out that "data" sent over the fiber-optic cable arrives 60ns earlier then assumed

      Why to they need to re-do the test? Isn't the point of this not that their raw data was wrong, but the calculations they did based on that data were wrong? The data should still be fine, they just used a dodgy figure when turning their raw data into a speed calculation.

      Kind of like measuring the time it takes someone to run a mile in order to calculate their average speed, getting puzzled as to how fast it was, then realising they only ran a kilometre - the raw time data is still accurate, you just need to

  • by Hatta (162192) on Wednesday February 22, 2012 @06:24PM (#39130591) Journal

    Is there any way we can pin this on Julian Assange?

  • by j. andrew rogers (774820) on Wednesday February 22, 2012 @06:24PM (#39130599)

    That's why I use Monster Cables for my neutrino experiments. It increases the roundness of the bass end, creates a punchier mid-range, and makes my neutrinos less superluminal.

  • Really, guys? the N and R are not that close together unless you're using the Dvorak layout or something.
    • by Shados (741919)

      hmm? I read it as fixing the system responsible for the correction. Not as fixing the connection (even though in this case, they're the same thing)

  • by Anonymous Coward on Wednesday February 22, 2012 @06:41PM (#39130805)

    I love the 'Faster than light neutrino' story. It shows something about how science works... an unconfirmed but sensational result captures our imagination. Though fascinating, it is treated with skepticism by scientists including the group publishing the results. Alternative hypotheses challenging the result are examined, and many discarded.

    Eventually the result will be supported by more experiments or found to be incorrect... maybe even the result of a loose cable.

    The neutrino story also shows something about how science is reported in much of the press... Unconfirmed but sensational results are presented as true. Preliminary challenges to the result are also reported as true. By the time the story is done, news outlets have misreported a number of contradictory claims as fact. No wonder a significant subset of the population doesn't understand or even believe science.

  • by silverpig (814884) on Wednesday February 22, 2012 @06:48PM (#39130869)
    Even the off-shored level1 tech support guy could have figured it out by reading step 2 of his manual.
  • Oblig XKCD (Score:5, Insightful)

    by Kittenman (971447) on Wednesday February 22, 2012 @06:50PM (#39130889)
    Right on the money ... http://xkcd.com/955/ [xkcd.com]
  • I use a Monster HDMI cable.
  • Joke (Score:4, Funny)

    by PPH (736903) on Wednesday February 22, 2012 @08:49PM (#39132013)

    The bartender says "We don't allow your kind in here".

    A faster-than-light neutrino walks into a bar.

  • by gweihir (88907) on Wednesday February 22, 2012 @09:40PM (#39132361)

    However the way to deal with this is to have several different models GPS units connected to several different computers and verify synchronization. That is not easy at the level of precision we are talking about here, though. So I do not blame them. And they wisely never did a sensationalist press=release, just "this is what we see and we do not understand it". Now they do. These things can happen.

  • by funkboy (71672) on Wednesday February 22, 2012 @10:15PM (#39132559) Homepage

    So, it seems that the previously calculated stddev was -5.9/+8.3ns [wikipedia.org], which is about double the certainty of the best COTS systems (it had better be, they're plugged directly into atomic clocks). Basically:

    "A loose connection between the fiber link from a GPS receiver to a computer is thought to cause the 60 nanosecond delay; tightening the connection makes the delay through the fiber decrease. However, additional data has to be taken to test the hypothesis. A second error with the crystal oscillator is expected to have lengthened the reported flight-time of neutrinos. Repeat tests with short pulsed beams have been scheduled for May. The two errors affect the result in opposite ways. The OPERA collaboration has not released quantitative estimates of how the errors affect the results, and expect to check the effects directly when a bunched beam is available later in 2012."

    So this thing is far from over...

  • by darrenm (1632751) on Thursday February 23, 2012 @12:50AM (#39133465)
    Einstein was seen chuckling to himself and mumbling under his breath "you didn't think it was going to be that easy, did you?"

This is a good time to punt work.

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