I’m a little torn about this: the Twitter machine and other social mediums have blown up about this story at Science Express, which claims that the faster-than-light neutrino result from the OPERA collaboration has been explained as a simple glitch:
According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos’ flight and an electronic card in a computer. 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.
I suppose it’s possible. But man, that would make the experimenters look really bad. And the sourcing in the article is just about as weak as it could be: “according to sources familiar with the experiment” is as far as it goes. (What is this, politics?)
So it’s my duty to pass it along, but I would tend to reserve judgment until a better-sourced account comes along. Not that there’s much chance that neutrinos are actually moving faster than light; that was always one of the less-likely explanations for the result. But this isn’t how we usually learn about experimental goofs.
Update from Sid in the comments: here’s a slightly-better-sourced story.
Update again: and here is the official CERN press release. Not exactly admitting that a loose cable is at the heart of everything, or even that the result was wrong, but saying that there were problems that could potentially invalidate the result.
Joel is right.
Shit can happen when leave the couch you make your hands dirty.
Just to make one thing clear: it doesn’t make the experimenters look bad to find a loose cable. Experiments are hard, and tiny glitches like this happen all the time.
What makes them look bad is announcing that neutrinos move faster than the speed of light without having checked things like this. Before you have a paper and a press conference for something like that, it’s your job (especially when nobody is directly competing with you) to do absolutely everything to make sure you haven’t made such a mistake. If that includes tearing every piece of apparatus apart and building it from scratch, so be it. Sure, you can throw it out to the community and ask people to check you, but for a result this big you first have to do everything in your power to check yourself.
OPERA uses an 8 km single-mode fiber optic cable that goes from the GPS receiver on the surface to the underground detector. OPERA reports that the delay of this cable is 40993.4 ns. Assuming this is the fiber cable in question, it is conceivable that they measured this delay before installation and then the delay changed due to the installation configuration being different than the measurement configuration, e.g., the cable is was curled up during measurement but not after installation. Bending a fiber optic cable can change the dispersion of the signal and induce signal loss. This seems more plausible than a bad connection resulting in a significant delay but is still speculation.
I agree with David Brown. In light of this discovery, the left side of Einstein’s Equations should be changed from:
R_{munu} – (1/2)Rg_{munu}
to:
R_{munu} – (1/2 + sqrt((60±10)/4) * 10**-5)Rg_{munu}
It follows from experiment! Rañada and Milgrom deserve next year’s Nobel Prize. Time to rewrite the GR textbooks!
@Tony Mach: By looking at several forms of empirical evidence, I arrive at the hypothesis that the basic problem is that the OPERA team failed to consider the effect of dark matter (or its Milgrom-equivalent). The dark matter (or its Milgrom-equivalent) causes a GPS timing problem. You might say that dark matter causes time to slow down more than standard general relativity theory predicts.
On pages 83 and 84 of Einstein’s “The Meaning of Relativity”, there are 3 fundamental conditions for the components of Einstein’s tensor of the gravitational potential. The first condition is the tensor must contain no differential coefficients of the Fundamental Tensor components of greater than second degree. The second condition is that the tensor must be linear in these Fundamental Tensor components of second degree or less. The third condition is that the divergence of the tensor must vanish identically. The first two conditions are necessary to derive Newton’s theory of the gravitational potential in the non-relativistic limit. The third condition is necessary to eliminate energy gains or losses from alternate universes. But does dark matter consist of gravitational energy that seems to derive from alternate universes? Consider the following:
Two Button Hypothesis of General Relativity Theory: In terms of quantum gravitational theory, Einstein’s general relativity theory (GRT) is like a machine with two buttons: the “dark energy” button and the “dark matter” button. The dark energy button is off when the cosmological constant is zero and on when the cosmological constant is nonzero. The dark matter button is off when -1/2 indicates the mass-energy divergence is zero and on when -1/2 + sqrt((60±10)/4) * 10**-5 indicates the mass-energy divergence is nonzero.
marshal sez: Like theorists. That’s what they do, try and make sense of new experimental results, and there is nothing wrong with it, even if those results later turn up short.
I hope you really meant to write “Like SOME theorists.”
#12 LMMI: exactly! Both Discover and Scientific American contributed to marketing a cable failure as one of the biggest science stories of the year, amazing and shameful.
@ David Brown, #30,
You are totally making sense. I see it! I completely agree with you. Have you published a paper on these results yet? I want to learn more! You are on to something big here!
re. David Brown
You have to realize that people see posts like yours and just see noise. Here is what you should do instead:
* Learn in detail the theories that you’re looking to improve.
* Show carefully and clearly why your model improves upon current mainstream models. If you truly want to succeed, it is important that you do this in a way that is sympathetic to the way physics is normally done, how physicists usually see research. i.e. Do not use blog comment sections to talk about your the details of your ideas. It never ever works! Distribute you work via papers, and only use LaTeX. If you have initial trouble putting papers on the arxiv then use vixra.org or something.
If you do not get this stage right then there’s a serious danger of torpedoing your own aims.
It is my experience that *very few* people in your position actually make the effort to do these things. I could probably count the number on my hand. It makes all the difference. Good luck!
re. Phil, for sarcasm to be done well, it has to be done with some precision.
Yes, David Brown, and might I add one more piece of advice:
Call 1/2 + sqrt((60±10)/4) * 10**-5 a name, like “Brown’s number”, and give it a symbol, such as B, for Brown. Then, your equation reduces to the neater, and more serious-looking:
R_{munu} – BRg_{munu} = 8*Pi*T_{munu}
@Tony Mach; I agree completely, it would have to be a home-made connection; commercial interfaces are DC-balanced and so are immune to having changes in attenuation appear as an apparent change in propagation delay. But for this to explain the problem, they’d have to be working with rise times on the order of 60ns. For people sophisticated enough to use 8km single mode fiber, that’s hard to believe.
An explanation I would believe (and a sign of miserable engineering) would be to leave the cable dark for 1/2 second and then on for 1/2 second. Then you could have some severe delays because (my guess is that) fiber amplifiers are almost always capacitively coupled. As far as evidence for this, Specracom’s 1PPS GPS synchronization output is 5V TTL; a natural thing (ooooops) would be to hook this up to the fiber through a TTL to fiber converter (the type that is just a straight buffer): Spectracom’s data is here: http://www.spectracomcorp.com/ProductsServices/TimingSynchronization/GPSTimeFrequencyReferences/SecureSyncSynchronizationSystem/tabid/1304/Default.aspx
Pingback: Zwei Fehlerquellen bei OPERA entdeckt – könnten Neutrinos schneller aber auch langsamer erscheinen lassen! « Skyweek Zwei Punkt Null
@Ted Danson: A study of the difficulties that Milgrom encountered in publishing his work indicates that someone else will be gain priority in publishing the Rañada-Milgrom effect in a refereed journal.
“I think few people appreciate that the main difficulty for DM is that the host of regularities pointed out by MOND, if taken as just a summary of how DM behaves and interacts with normal matter, suggests that these two matter components are coupled and correlated very strongly in many ways. … if MOND does turn out to have some truth to it, the fact that it has encountered so much opposition will just show how nontrivial a thought it was.” — Mordehai Milgrom, interview entitled “Dark-matter heretic”, American Scientist, Jan.-Feb. 2003, Vol. 91, #1, p. 1
http://www.americanscientist.org/issues/pub/dark-matter-heretic
Consider the following argument:
Premise 1. There is overwhelming empirical evidence in favor of Milgrom’s non-relativistic MOND, according to the work of Milgrom, McGaugh, and Kroupa.
Premise 2. For low gravitational accelerations, non-relativistic MOND is approximately equivalent to the Rañada-Milgrom effect, because the approximate equivalence is easily shown by a scaling argument.
Premise 3. The approximate value of the dark-matter-compensation-constant is given by the Pioneer anomaly, and this value is approximately confirmed by the OPERA neutrino anomaly.
Conclusion. The Rañada-Milgrom effect is approximately valid, at least for low gravitational accelerations and non-relativistic velocities.
Is Milgrom’s non-relativistic MOND incorrect? Is Einstein’s general relavity theory 100% correct? Is the Lambda CDM model (LCDM) 100% correct?
http://en.wikipedia.org/wiki/Lambda-CDM_model
I quote Prof. Dr. Pavel Kroupa from a (Nov. 1, 2011) e-mail,
“My criticism is not based on me not liking dark matter, but is a result of rigorous hypothesis testing such that, from a strictly logical and scientific point of view, LCDM is definitely not a viable model of cosmological reality. I do not write such statements because I do not like LCDM and its ingredients, but because every test I have been involved with falsifies LCDM. At the same time, the tests of MOND we performed were done on the same footing as the LCDM tests. The MOND tests yield consistency so far. I am not more “fond” of MOND or any other alternative, but the scientific evidence and the logical conclusions cannot be avoided. And it is true, I must concede, that MOND has an inherent beauty which must be pointing at a deeper description of space time and possibly associated quantum mechanical effects which we do not yet understand (compare with Kepler laws and the later Newtonian dynamics).”
Pingback: I have a plan for faster-than-light travel now | Pharyngula
@ David Brown:
‘@Ted Danson: A study of the difficulties that Milgrom encountered in publishing his work indicates that someone else will be gain priority in publishing the Rañada-Milgrom effect in a refereed journal.’
If you’re worried about getting credit for having the idea first, I assure you that it would be sufficient to put your work on a non-peer reviewed website such as Vixra.org. Stop being so lazy.
#22: Apparently, some people did. What’s bizarre is that it took approximately a week for grounded theorists to publish a couple devastatingly fatal critiques of the notion of FTL neutrinos, as if the approx. 100 gagillion data points confirming SR weren’t enough. But somehow the “hey, it could happen” notion lived on because, hey, neutrinos of some energy that we hadn’t yet gotten around to clocking (because it would be pretty low priority kind of investigation) just might take a shortcut through extra dimensions. I mean, hey, you never know, right? And that’s the beauty of such extensions of reality: You really never know!
Pingback: FTL Neutrinos: Closing In on a Solution
Come on, Sean. The experimenters make a bone-head mistake, or relativity is wrong. Which is more likely?
Pingback: FTL Neutrinos: Closing In on a Solution | Light a Rocket
Interview, in German, with an Opera scientist about the problem : http://www.faz.net/aktuell/wissen/physik-chemie/interview-ueber-die-moeglichen-fehlerquellen-messfehler-koennten-ueberlichtgeschwindigkeit-erklaeren-11660876.html
Translation (in the first comment) : http://profmattstrassler.com/2012/02/24/finally-an-opera-plot-that-makes-some-sense/
The crucial bit :
We do not know how crooked the plug actually was at the time of our measurements last year. Sub-sequentially we do not know the actual time delay.
So, they just don’t know whether the neutrinos were superluminal, subluminal, or what.
I still think they were synced on the trailing edge of the timing pulse.
An informed source says a bad cable to Paul’s Hofner left-handed bass is what really broke up the Beatles.
Check your cables !!!
@ Sean C; If that includes tearing every piece of apparatus apart and building it from scratch, so be it.
Sure way to introduce new errors.
Time barrier was broken in 1979. The N.S.A. knows all about it.
A word-choice note: It should be “social media,” not “social mediums.” “Mediums” is the plural of the kind of “medium” who holds a séance—or were y0u trying to get into better sync with the new Discover Magazine, the one that runs articles about bogus experimental proof of ESP?
@Ted Danson & @Phil:
See http://vixra.org/pdf/1202.0083v1.pdf “Anomalous Gravitational Acceleration and the OPERA Neutrino Anomaly”. What are your criticisms?