Forgot your password?
typodupeerror
Science

Can Relativity Explain Faster Than Light Particles? 315

Posted by timothy
from the old-woman-your-lap-for-a-minute dept.
gbrumfiel writes "Two weeks ago, researchers claimed particles called neutrinos were travelling faster-than-light and violating the laws of special relativity. But now it looks as though general relativity might be behind the experiment's unusual result. An independent analysis claims that the original experiment, known as OPERA, failed to take into account differences in earth's gravitational field between the neutrino source and the OPERA detector. As Nature News reports, gravity can distort time according to Einstein's theory, and the effect could explain why neutrinos appear to arrive 60 nanoseconds ahead of schedule. The OPERA team is now reviewing the new analysis."
This discussion has been archived. No new comments can be posted.

Can Relativity Explain Faster Than Light Particles?

Comments Filter:
  • Except with all the math half-way worked out.

  • Dear CERN, (Score:3, Funny)

    by Anonymous Coward on Thursday October 06, 2011 @01:26PM (#37628384)

    Nice try.

    Sincerely,
    Einstein

  • by Steve Max (1235710) on Thursday October 06, 2011 @01:28PM (#37628406) Journal

    They are reviewing their own paper to make their methods clear. FTFA:

    "Dario Autiero of the Institute of Nuclear Physics in Lyons (IPNL), France, and physics coordinator for OPERA, counters that Contaldi's challenge is a result of a misunderstanding of how the clocks were synchronized. He says the group will be revising its paper to try to make its method clearer."

    Meaning: Contaldi didn't understand how OPERA did it, and thought they had commited a somewhat stupid mistake. OPERA says they didn't make that error, and that they'll rewrite that part of the paper to make this clear. In other words, this is not news at all.

    • Mod parent up +5 informative - and thread over.

    • Even if it is just a matter of clarifying the paper, it's still peer review in action. When OPERA responds, Contaldi will have the opportunity to review their clarifications. Maybe he'll respond again and point out that OPERA is still in the wrong. Or maybe he'll be satisfied and move on. This is how science is done. How is that not news?

      • by Surt (22457)

        It's not news for one of two reasons, because one of two things is true:

        Contaldi has poor reading skills. 'Peer review' is of low value from people who can't understand straightforward explanations that were understood by others.

        or:

        Science is proceeding as normal, and the outcome is still unknown .

        Wake me when science reaches a conclusion, every minor typography fix on this paper is not newsworthy.

        • by vadim_t (324782)

          Contaldi has poor reading skills. 'Peer review' is of low value from people who can't understand straightforward explanations that were understood by others.

          I think you're being too harsh. Clarity is important. Misunderstandings get people on the wrong way. I think it's much better to add a clarification than to complain about people misreading the work.

    • Oh, it's news all right. Just not end-of-the-world-as-we-know-it news. As pointed out in TFA, it's awfully hard to critique the experiment unless you're there seeing exactly what has been done. While I don't find it surprising that a few printed (or electronic) pages cannot describe hundreds of tons of equipment and countless hours of work it does speak to the complexity of modern science.

      You wonder how much that is published isn't repeatable or understandable. Dropping rocks off off buildings and count

    • "Dario Autiero of the Institute of Nuclear Physics in Lyons (IPNL), France, and physics coordinator for OPERA, counters that Contaldi's challenge is a result of a misunderstanding of how the clocks were synchronized. He says the group will be revising its paper to try to make its method clearer."

      The heck with that! What I want to know is: How can a company that gives away a free browser possessing only a minuscule market share afford to employ a physics coordinator?

      • I was about to mod you funny but then I tought it better: while he's not on peasant wages, the fact remains that even "just" senior engineers from Opera will probably earn more than that guy.

        How the hell am I going to mod something funny when it makes me feel so depressed?

    • Meaning: Contaldi didn't understand how OPERA did it, and thought they had commited a somewhat stupid mistake. OPERA says they didn't make that error.

      OPERA says that they didn't make that error. But, they also learned about the mistake only through Contaldi's challenge.

      Causality has been a bit off recently.

  • by hchaos (683337) on Thursday October 06, 2011 @01:29PM (#37628418)
    NO ONE considered the time distortion of gravity? I mean, sure, it's the first time that the time distortion due to gravity has ever been significant in any practical application, but it's still a fundamen... wait, it's not the first time? You're saying that there's an 18-year-old system that relies on this principle to work properly? How many people use this obscure system? Every single person in the civilized world? You'd think that at least one of these researchers would have heard about it, then.
    • by Bucky24 (1943328) on Thursday October 06, 2011 @01:33PM (#37628490)
      I hate to say this, because I know it's probably painfully obvious to most people, but I have no idea what you're talking about.
      • Re:Seriously? (Score:5, Informative)

        by LateArthurDent (1403947) on Thursday October 06, 2011 @01:41PM (#37628634)

        I hate to say this, because I know it's probably painfully obvious to most people, but I have no idea what you're talking about.

        He's talking about GPS. In order for the triangulation to work correctly, relativity must be taken into account [ohio-state.edu].

        That said, another poster pointed out [slashdot.org] that the researchers apparently did account for the effects of gravity when synchronizing their clocks. The paper just wasn't sufficiently clear on that point, and they're rewriting that section.

        • Here's my thought, probably not worth the time I took to write it.

          IF General Relativity is wrong, then all measurements depending upon it are also wrong. To Verify the results, we would need another form of measurement that doesn't depend on GR for accuracy at the distances and speeds we're using.

          We are so dependent upon our view that if the glass we're viewing through is distorted, everything that follows would also be distorted. GR may be much like Newtonian theory of gravity, where it works fine in many

      • by WCguru42 (1268530)

        Global Positioning System (GPS)

      • I think he's trying to get at the fact that time distortion of gravity is well known and that GPS (the 18 year old system) wouldn't work or would not work well if this wasn't taken into effect.

        I am not sure that his rant is correct though, it's a small (nanosecond according TFA) difference. GPS has known uncertainties and this may very well be much smaller than known / common causes of error. It's not like the US military planned on having physicists using the GPS system for off the wall research. They w

        • by gblackwo (1087063)
          According to the link, for GPS, the relativistic difference is about 38,000 ns per day, or approximately .44 ns per second.
      • I hate to say this, because I know it's probably painfully obvious to most people, but I have no idea what you're talking about.

        Don't let that get in the way of giving your opinion! ;)

      • by matrim99 (123693)
        "What is GPS?", Alex.
    • Re:Seriously? (Score:5, Insightful)

      by Surt (22457) on Thursday October 06, 2011 @02:01PM (#37629058) Homepage Journal

      They did consider it, the critic had a brain fail and misunderstood their paper. The researchers are doing him a kindness and 'clarifying' it for him, even though everyone else got that they had, in fact, accounted for this.

      • Re: (Score:3, Insightful)

        by Maritz (1829006)
        Yes. Contaldi has made a tit of himself with this critique. The real error is likely to be very subtle.
    • They understood GPS and used it to synchronize their clocks - if you read the paper the GPS error was still on the order of 100ns - they had to then sychronize their clocks by taking an atomic clock and moving it from one location to the other to determine an additional correction term - the problem the author points out is that correction term is _path_ dependent - it depends on the exact route of the journey and if any stops are made along the way - in addition I believe the author points out that the neu
  • This news is disappointing, but expected. I don't mean that I expected someone to give this particular explanation, just that I expected someone to provide an explanation that did not require the neutrinos to travel faster than the speed of light.
  • WRONG! (Score:5, Informative)

    by arkham6 (24514) on Thursday October 06, 2011 @01:31PM (#37628456)
    The researchers made no such claim! In fact they explicitly said they disbelieved they saw faster than light particles, and that they thought their data was faulty somewhere. But what they DID do is ask for other scientists to check their data and find their data, and if possible recreate the experiment to help track down where the error was.

    THIS IS CORRECT SCIENTIFIC PROCEDURE!
    • Re: (Score:2, Interesting)

      by 0123456 (636235)

      THIS IS CORRECT SCIENTIFIC PROCEDURE!

      Aside from the part where it gets plastered all over the media rather than a quiet discussion with their peers.

    • by ljw1004 (764174)

      I think you're reading the surface words rather than the universally-understood subtext.

      It's like when a scientific paper says "We were unable to replicate the results of Jones et al".

      This doesn't mean "we were unable to replicate the results of Jones et al". Instead it means "Jones et al were either a bunch of nincompoops who didn't understand what they were doing, or they actively falsified their work".

      Or when you call someone a poopie-head. It doesn't mean you think their head is made of poop; it means y

    • by Twinbee (767046)

      I think maybe you overreacted a bit there? I'm sure the false cold fusion fiasco left a bitter taste in the mouth, but the announcement of this was nothing like that, and was much more careful. Yes the news topic here changed the meaning slightly, but you honestly think as a result that people might harpoon CERN and say "You promised these particles were faster that light, and you were wrong - shock! horror! etc.".

    • by arkham6 (24514)
      find their error, not find their data. Blah.
    • challenges to research are actively encouraged in some aspects of science whereas they are unfortunately denounced in others. I am glad to see this team inviting others to find the faults if any, now to see this applied to more politically sensitive subjects would be nice

      • challenges to research are actively encouraged in some aspects of science whereas they are unfortunately denounced in others. I am glad to see this team inviting others to find the faults if any, now to see this applied to more politically sensitive subjects would be nice

        You are not the first person to drop this in to this discussion so I'll answer that. There are two fields that people typically mean by "others" evolution and climate change; the main other ones I can think of are RF radiation risks and cigarette safety. In both of these, I, a layman from each field, have been able to quickly identify fundamentally missing literature from each challenge I have seen. I don't mean "they were wrong"; I don't mean "they misunderstood". I mean, they either failed to find th

    • Scientists: "Well, we have this really funny phenomenon here where we are measuring neutrinos as moving faster than the speed of light. We are pretty sure that this is an error either in our calculations on in the calibration of our equipment, but we have yet to find any flaws in our methodology. Here is the data that we have accumulated, in the hope that a distributed effort around the globe will help us get to the bottom of this.

      Media: "Scientists say: FUCK YOU EINSTEIN!!! YEAH THAT'S RIGHT MOTHERFUCKE
  • "Speed" (Score:4, Interesting)

    by Belial6 (794905) on Thursday October 06, 2011 @01:40PM (#37628608)
    Are they using some other measurement of "speed" that isn't distance / time? It seems that slowing time down and going the same "speed" has the same net effect as going faster than the speed of light.
    • by guspasho (941623)

      All of relativity is premised on the (very consistently verified) notion that speed isn't just distance/time as Newtonian mechanics would understand it, and that you must also take in to account the effects of gravity on spacetime.

    • by frith01 (1118539)

      The article states that because they moved the atomic clock used for measuring time, their time synchronization would be different for the clock while it was in italy, then when the clock was in switzerland. The difference in time synchronization is what they measured, not the speed of light.

      Of course, they knew about this effect, & tried to off-set it by using GPS signals from the same satellite to correct. TFA says that GPS signal has error in time sync about 100ns, which is in scale with their

    • by snowgirl (978879)

      Are they using some other measurement of "speed" that isn't distance / time? It seems that slowing time down and going the same "speed" has the same net effect as going faster than the speed of light.

      To your first question, ... yes, kind of. But to point, the article apparently suggests that they made an error in measuring the amount of time that the particles traveled the distance. This isn't much different than my acknowledgement that a 60 ns error could be accounted for by an ~60 foot discrepancy in the distance measurement. (Note: when I say "measurement" here, I'm really meaning more "calculation"... at these exacting standards measurement alone is insufficient, you need to make multiple measuremen

  • In their original paper on arxiv they reported on using the ETRF2000 reference frame ( IERS [iers.org]) to determine the distance between the neutrino source at CERN and the detector at Gran Sasso. This reference frame already includes effects from general relativity.

    If it turns out that time dilation due to gravity is the reason, then the error must be in the ETRF2000 or it was applied incorrectly in this case (Neutrinos moving from A to B). Considering that hundreds of people work on this project it seems unlikely t

  • I personally chalk it up to the measurement between the emitter and the detector.

    Yes I know they say they are very confident within a margin of error and that amount they are observing is within that margin of error so it must be right??

    Personally I aint gonna start changing C based upon their confidence that their variation is within the margin of error that they say is within the margin of error of the distance between the gun and the target since everything else in GR & SR has been demonstrated corre

  • failed to take into account differences in earth's gravitational field

    Even if they didn't account for it, so what?
    The Schwarzschild solution for Time dilation has a C squared in the divisor.
    Unless I'm doing the math wrong, It wouldn't even amount to 1 nanosecond, much less 60.

    • by HuguesT (84078)

      The article claims they had to move a device between the two locations to synchronize the clocks, and that not all GRT effects have been taken into account while this device was moving.

  • "let us assume that the TTD was stationary at the LNGS site for 4 days while the appara-tus for clock comparison was set up. Using the value of V/c2 quoted above this would result in a total shift of t 30 ns."

    Let us assume a scenario which fits our desired outcome has actually occured without any supporting evidence since our own figures fall far short of a cogent explanation for the discrepancy.

    Let us further overlook the fact PTB was mearly used to independantly *VERIFY* the nanosecond level clock synchr

  • Actually, the theory of special relativity has no problem with particles going faster than light. The problem lies with accelerating particles from slower than light in vacuum to faster than light in vacuum. Or, for that matter, with slowing down from faster to slower than c.
    • by Chris Burke (6130)

      Actually, the theory of special relativity has no problem with particles going faster than light.

      Yes it does [wikipedia.org], since SR assumes a causal universe. The sending of any kind of information* faster than light results in a violation of causality according to some frame of reference. And SR also assumes the relativity principle that the laws of physics hold for all frames. But once given FTL travel/communication, you can create a scenario where causality is violated according to all reference frames and create a paradox.

      * And thus particle, or anything else that could affect the outcome of some experiment

  • by jonbryce (703250) on Thursday October 06, 2011 @02:29PM (#37629528) Homepage

    Would it be possible to have neutrino generators and detectors at both sites and test the speed in both directions? That would probably mean testing the speed between CERN and Fermilab. That way, if there was an error in clock synchronisation, it would show up because the neutrinos would take longer in one direction than the other.

    • by blair1q (305137)

      Sure. Build another LHC to bookend the problem.

      Actually, if the result continues to hold up, that may be a justifiable use of $100e9...

      • by jonbryce (703250)

        They didn't use the LHC to generate the neutrinos, and Fermilab won't be using their decommissioned Tevatron to generate theirs when they try to replicate the experiment.

  • by riverat1 (1048260) on Thursday October 06, 2011 @05:33PM (#37632404)

    After I saw this quote I figured they'd have to find some error in their observations. (Emphasis added.)

    "...If the observation is confirmed, it may be the most important discovery in science in the last 100 years.

    "However, a big fly in the ointment is the supernova in the Large Magellanic Cloud, which sits just outside our galaxy 168,000 light-years from Earth. It was first seen by the naked eye on February 24, 1987. Three hours before the visible light reached Earth, a handful of neutrinos were detected in three independent underground detectors. If the CERN result is correct, they should have arrived in 1982. So, if I were a wagering man, I would bet the effect will go away because of some systematic error no one has yet been able to think of."

    (Quote stolen from Quark Soup [blogspot.com])

  • a bunch of papers (Score:5, Informative)

    by bcrowell (177657) on Thursday October 06, 2011 @05:50PM (#37632594) Homepage

    The arxiv blog recently had a roundup of papers discussing this: http://www.technologyreview.com/blog/arxiv/27212/ [technologyreview.com] They fall into three groups: (1) Suggestions of how the experiment might have given a wrong result. (2) Theoretical arguments that constrain the interpretation and make the result seem implausible if taken at face value. (3) Theoretical papers saying what it could mean if it really was new physics. The Nature article seems to show that the Contaldi paper was based on a misunderstanding of how the experiment was done. However, the Nature article points to a new paper by Henri that wasn't included in the arxiv roundup: http://arxiv.org/abs/1110.0239 [arxiv.org]

FORTRAN is a good example of a language which is easier to parse using ad hoc techniques. -- D. Gries [What's good about it? Ed.]

Working...