back to article Can general relativity explain the OPERA neutrino result?

CERN’s decision to release data about its “superluminal neutrino” experiments at an early stage is providing the world with a rare insight into the process of scientific peer review. Another small step in that process in relation to the fascinating OPERA results asks whether general relativity can be called in to help explain …


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  1. asdf


    >we’ll have had our most detailed demonstration of why science works.

    That is until religious ideologues get elected and tell us the world is 5,000 years old and that natural selection is a lie.

    1. Jonski

      Science. It works, bitches.

      And it works because scientists are always ready to accept they could be wrong.

      Religious creotards have no appreciation of this, and any attempt made to fit their ideology to fact is inherently doomed to fail- because they can't accept that the rules they use to prove science for their purpose are the same rules that negate their purpose out of hand.

      Oh, and by definition, nothing in this universe is "supernatural" and *everything* is a suitable candidate for scrutiny by the scientific method.


      1. amanfromearth


        "And it works because scientists are always ready to accept they could be wrong"

        Most scientists are. Strangely, climate scientists are not in this group.

      2. BristolBachelor Gold badge


        I prefer this one, and it is actually relevant too!

        It's actually given me an idea; (Unfortunately all the people here already don't believe it and therories including the one about moving atomic clocks too fast through gravity fields are already discussed at lunch)

      3. apjanes

        Highly irritating

        Why I find highly irritating is the way people (particularly readers here) seem to think that there is a war between science and religion where scientists are the rational, open-minded, educated, good guys and those who believe a religion are blind, irrational, dim-witted, "creotard", baddies. Nothing is farther from the truth. Have you never heart of advanced, intelligent, open-minded, scientists who have developed religious faith BECAUSE of what science has taught us, not in spite of it? Have you never heard of scientists that doggedly stick to a wrong conclusion in spite of all evidence because of their own presuppositions which they are unwilling to release? There are both open-minded and dogmatic individuals in both camps.

        Unfortunately, comments like this that try to lump all scientists or all those of religious conviction into a single stereotypical basket simply, in my opinion, illustrate a lack of open-minded intelligence of the poster and all those who give it the thumbs up.

        1. Shakje


          Scientists *are* the rational ones. Belief from faith is by definition irrational. Look, if you have faith that a god is protecting you and will do what is best for you, if you have *complete and utter* faith in it, you should have no problem walking off a cliff, but rationality always prevails (along with some sort of irrational justification for why it's not to do with not having enough faith). Scientists *can* be dogmatic and unwavering in their acceptance of something, but religious believers *have* to be dogmatic in the fundamentals, at the very least. Do you see the difference?

        2. Adrian Midgley 1


          "Have you never heart of advanced, intelligent, open-minded, scientists who have developed religious faith BECAUSE of what science has taught us, not in spite of it?"


          You were perhaps going to give an example?

    2. Anonymous Coward
      Anonymous Coward


      As the folk at WBC would say....

    3. Mme.Mynkoff

      Scientists ARE the new religious ideologues

      If you disagree with their unsupportable hypothesis, you are a heretic and must be cast out of the temple.

    4. Full Mental Jacket

      Going to have to call you out on this one

      Science can be just as dogmatic as religion, as the guy who discovered quasicrystals found out.

      From -

      "Dr Shechtman had to fight a fierce battle against established science to convince others of what he had first seen in his lab at the National Institute of Standards and Technology in Washington - formerly called the National Bureau of Standards - on an April morning in 1982.

      For years, the researcher was "ridiculed" and "treated badly" by his peers, he recounts."

      This years Nobel Chemistry prize winner...

      1. meh1010

        @Full Mental Jacket - Not really, as the "science establishment" eventually gave him a Nobel prize (fair enough, he was treated badly but hardly in the same scope as religion)

        1. DeVino

          Don't confuse science with scientists

          See if I can get this right :-)

          The old duffers say.

          1) It's bollocks

          2) It's not bollocks but it's irreproducible

          3) It's brilliant and I have always stated that it was

          The very nature of peer review means that it's open to abuse by

          folk who are emotional, envious and/or unimaginative but that does not invalidate the process.

          There is a great story about the bloke who proposed Tectonic plate theory.

          He was repeatedly vilified by his peers who then led a candle-lit procession

          of contrition to his widow's house when the theory was proved correct.

      2. Jolyon


        "This years Nobel Chemistry prize winner..."

        So it took some work for him to establish himself but he has done so and precisely because of the scientific review processes. He now has the top dog award. Some of his peers may have been dogmatic but 'science' wasn't.

        Now imagine Galileo becoming pope . . .

      3. cyborg

        "Science can be just as dogmatic as religion, as the guy who discovered quasicrystals found out."

        Science is non-dogmatic by definition.

        Scientists on the other hand are just humans who are obstensibly practising the methodology of science. Failiure to do so is not a failure of the method but the scientist.

        For the dogmatic religion failing to adhere to the dogma makes you a bad practitioner of that religion. No different really - people are not merely templates over which philosophical systems can be neatly pasted.

      4. BristolBachelor Gold badge

        @full Mental Jacket

        Yeah, but they just told him that he was crazy, and it wasn't possible.

        They didn't lock him up, burn him at the stake, or execute him for being a heretic.

    5. Anonymous Coward


      That is until some 'blindly partisan advocate or adherent of a particular ideology' (to use the Webster's definition of ideologue) interrupts the scientific discussion with spam.

  2. Jim O'Reilly

    Science 1: Hype Nil !

    This is the way the best science moves forward.

    Despite all of the "faster than light" discussion, another 'oops' for relativity is explaining how particles with an apparent non-zero rest mass travel at or very near the speed of light. Perhaps the issue here is that in fact these particles never move slowly, and so what we see is not rest mass but energy and that the particles are more like photons than fundamental particles. All of this confuses the quantum model, so science will be buzzing with this for a good while.

    It's a pity we turned off Fermilab's accelerator.

    1. Anonymous Coward
      Anonymous Coward

      Why is it a pity?

      The neutrino sources at Fermilab come from the Booster ring and the Main Injector, not the Tevatron. In fact, shutting down the Tevatron is good for those experiments, as more protons will now be delivered to them, and not the collider experiments.

    2. Destroy All Monsters Silver badge

      "explaining how particles with an apparent non-zero rest mass travel at or very near the speed of light"

      I don't see why this is a problem. With small rest mass and high kinetic energy, the only thing that goes to c is v.

    3. This post has been deleted by its author

  3. Anonymous Coward
    Anonymous Coward

    Synchronise using 4 clocks

    Use 4 atomic clocks, 2 at the sending station and 2 at the receiving. The 2 clocks at each station are synchronised with each other. One clock from each station then travels to the other station. Each clock sets out at the same time (as best as it can be calculated) and uses exactly the same path and speed to the other station. The clocks can then be compared and any effect from the transportation calculated to see if it is large enough to cause the observed results.

    Time dilation should issues should be minimised as they travelled through the same non-uniform gravitational potential (although in opposite directions).

    1. K. Adams

      Minimised, yes. Completely "cancelled-out," no...

      Unfortunately, there's this big rotating gravity-encumbered ball called the Earth which needs to be taken into account...

      This is all because of a phenomenon called "frame dragging," in which a rotating mass is seen to pull the local space-time tensor around with it in the direction of its rotation. It is the frame dragging effect (also known in loftier scientific circles as the "Lense–Thirring effect") that causes the orbit of an object revolving around the rotating body to undergo precession, in which the apogee of the orbiting object advances slightly in the direction of the central body's rotation.

      The magnitude of the effect is very small (one part in a few trillion for any given rotating mass/orbiting object system, although for hyperdense rotating bodies like neutron stars and black holes, one part in a few trillion could still be quite significant), and thus difficult to detect. Even so, the effect is thought to be very real, and scientists spent a lot of time and effort trying to isolate it experimentally (the most famous being the lavishly expensive "Gravity Probe B" mission).

      1. Allan George Dyer Silver badge


        Stop the world, repeat the experiment.

        The one with the celestial mechanic kit in the pocket, please.

      2. Anonymous Coward
        Anonymous Coward

        Clocks A and B are at sender, C and D at receiver. B and D travel to other station. You can now use the following formulae to calculate the maximum impact of any relativistic effects: (A-D) - (C-B). If this is less than 60ns then it doesn't explain the phenomenon.

        1. Tom Chiverton 1

          Wont work, one of the moving clocks is going the opposite way through the frame for a start, plus the random changes to the gravity field wont happen the same way to both.

    2. Adrian Midgley 1

      "The clocks can then be compared"


  4. nyelvmark

    (and most often, only because the journal decides to throw some bones at the general media)

    That sounds to me a bit too much like the Sun-reader's "The gummint never tell us anything".

    There's nothing to prevent popular media employing teams of scientists to read all the current science, just as there's nothing to prevent the Sun-reader reading the Telegraph or the Guardian.

    1. Arctic fox

      "just as there's nothing to prevent the Sun-reader reading the Telegraph or the Guardian."

      Being near illiterate might hinder them somewhat.

      1. GitMeMyShootinIrons


        I'm sure that Kandi, 18, from Essex, our top heavy lovely would disagree - see page 3 for more!

  5. J 3

    Not constant

    "that theory considers lightspeed to be the cosmological constant, the same everywhere (in our universe at least) and unbreakable"

    Not constant, if I remember correctly. The *maximum* speed of light in a vacuum is fixed, but light can move slower than that maximum speed. But IANAP, so I might be misremembering the basic physics a biologist learns in college...

    1. Colin Miller


      but a unqualified "speed of light" is to taken as meaning "The speed of light in a vacuum".

    2. Dave Bell

      It's the speed of light in a vacuum that's the constant. Your recollection is correct. Relativity comes from a need to explain why the speed of light doesn't depend on the direction the observer is moving.

      Strictly, faster than light gives mathematically valid results, but has other implications.

      I wouldn't worry about this result until we get an outbreak of blue phone-boxes.

      1. DJO Silver badge

        "Strictly, faster than light gives mathematically valid results, but has other implications."

        Yes, mass as an imaginary number does certainly have implications.

        Bonus question: What colour does a red shifted blue policebox appear as?

        1. John G Imrie


          It's what all that dark matter is made of .

    3. This post has been deleted by its author

      1. Chris 3

        Indeed Indeed

        I ermmber wondering as a youngster whether we could travel backwards in (local swimming pool time) if we sat submerged in a pool full ofa substance through which light travels rather slowly.

        Actually, that still puzzles me.

  6. loopy lou

    Not what is usually meant by peer review

    This is gold standard peer review, not what is normally understood as "peer review" in the context of the media saying "it was peer reviewed so it must be right". Here lots of the best people are interested in getting to the bottom of the issue and real science is being done in the process.

    Normal peer review is rather less edifying. The hundreds of thousands of papers submitted to journals each year all have to be read by other scientists to weed out glaring errors, and dodgy claims, but very few get the kind of scrutiny this result is getting. I've certainly ticked the "accept" box on occasions after a couple of revisions thinking "well, it could be better but its not obviously wrong and no-one is going to read this paper anyway".

  7. Anonymous Coward
    Anonymous Coward

    Keep it up!

    Nice to see solid, dispassionate articles like this about science on The Register instead of the usual science-bashing conspiracy theory stuff.

    1. nyelvmark

      There's a bit of a difference between science-bashing and scientist-bashing.

  8. Anonymous Coward
    Anonymous Coward

    Not the LHC

    The SPS, duh

  9. Michael 31

    Remember 1987

    When supernova 1987a was observed in 1987 the visible signal and the neutrino arrived close enough together to establish that the neutrinos were travelling within 1 part in 10^9 of the speed of light. i.e. the signals peaked within about one hour of each other on a transit time of 160,000 years.

    Now admittedly these were electron neutrinos not tau neutrinos (at birth anyway) . And also If neutrinos travelled 1 part in 10^5 faster the neutrino peak would have been1.6 years in advance of the light and so might not have been noticed. But observations such as this should make us look at the OPERA experiment sceptically. It's a really ambitious measurement. They fired 10^20 neutrinos over 3 years but only observed 16,000 events - i.e. they only observed 1 in every thousand million, million neutrinos. That makes it tough to do timing! Establishing the timing and distance are both very difficult and despite their extensive checks, a small error is entirely possible.

  10. Graham Marsden

    One of my favourite quotes...

    ... From Isaac Asimov:

    "The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' (I found it!) but rather, 'Hmm... that's funny...'"

  11. salerio

    time resolution

    "Since GPS clocks are only managed to 100 nanosecond accuracy,"

    That's about 30 light meters is this 100 ns accuracy correct? hmmm wikipedia is claiming +- 10ns

    1. Richard 12 Silver badge

      For position accuracy you're actually looking for the delta between the time signals from the satellites - you don't know exactly how far away any of the satellites are, only the relative distances of them.

      For clock accuracy, you need to know the absolute distance to the satellites, and that has bigger error bars than the delta.

  12. Anonymous Coward
    Anonymous Coward

    Send a note to IPCC

    <quote>By the time OPERA is either settled or falsified, we’ll have had our most detailed demonstration of why science works.</quote>

    And the most glaring counter example of why "Climate Science" isn't (science).

    1. NomNomNom


      if this was climate science you deniers would be up in arms at the idea that the scientists were questioning the experiment.

      You would make trite statements like "when the observations don't match the theory, you throw away the theory"

      1. Anonymous Coward
        Anonymous Coward


        If this was climate science the observations would be hidden in a CENSORED directory and never see the light of day without an FOI request.

  13. Michael J Burns Silver badge

    My fellow physicists are making this too complicated.

    There are a lot of less exotic things that still need to be examined. For example, the thermal coefficient of expansion of granite (and most rocks) is on the order of 10 ppm/C (parts per million per degree Centigrade). Granite is 70-95ppm/C, Basalt is 80-95ppm/C, Sand stone is 90-120 ppm/C, Lime stone is 60-90 ppm/C, etc.)

    The distance between CERN & OPERA was about 730km. That means that if the average temperature of the rock between CERN & OPERA changed by 1 degree C over the course of the seasons that this experiment took place, that distance changed by something on the order of 5 meters. Or inversely, for that distance to have stayed within the claimed accuracy of 20cm, then the average temperature of the rock between CERN & OPERA changed by less than 0.04 degrees C over the course of the seasons that this experiment took place. Is that reasonable? I don't know. But this type of "mundane" explanation is a hell of a lot more likely an explanation than some exotic explanation on the edge of physics.

    1. Tim Starling

      Edge of physics?

      Gravitational time dilation was identified as a consequence of general relativity in 1907 and confirmed in 1959. Calling it the "edge of physics" is like calling sliced bread the "edge of baking".

      1. Michael J Burns Silver badge

        The reported "velocity" of these neutrinos is only 1.000025 times the speed of light (c). My point is that the explanation is likely a mundane apparatus issue. As the OPERA paper points out and cites as it's reference #6, theirs is not the first report of neutrinos traveling faster than light. The MINOS Collaboration in 2007 measured neutrinos "velocities" of 1.000050 times the speed of light during their neutrino mass measurements (Phys. Rev. D 76 (2007) 072005.). Only the MINOS Collaboration didn't make a big deal of it for a number of reasons. For example, as a number of people have pointed out, faster than light neutrinos should have very observable effects, such as emitting Cerenkov radiation which occurs when a particle's velocity exceeds c/n, where n is the index of refraction (n=1 in vacuum).

    2. Michael H.F. Wilkinson Silver badge

      The 60ns difference equates to 18 m

      I trust there has not been an 18m shift in position, as that is earthquake magnitude. The mean temperature of rock beneath the ground is really stable, simply due to its HUGE thermal capacity, and high degree of thermal insulation. This is why (wine) cellars often have high thermal stability.

      Previously, the peculiar, apparently superluminal motion of jets in quasars and active galaxies could be explained elegantly by invoking special relativity. by assuming the jet is traveling at near light speed almost directly towards us. Here general relativity may well be an explanation (but it may not)

    3. Anonymous Coward
      Anonymous Coward

      Given the depth of rock then a change of less than 0.04C is reasonable.

    4. Mark #255

      I don't think they/we are

      There are graphs in the original paper showing the drift in separation over the experiment's period. You can even see the jump (of a few cm) due to an earthquake.

      Precision over distances really is a done deal - even my phone can pinpoint me within 2m, so I'm not surprised with their claim of 20cm accuracy.

      Anyway, I'm with Mr Chirgwin on this - either we get New Physics (unlikely), or we get to see Science In Action (tm).

    5. This post has been deleted by its author

    6. Michael 31

      They monitored the distance continuously

      They monitored the distance continuously and saw drifts due to various sources including a 7 centimetre jump after the L'Aquilla earthquake

    7. Adrian Midgley 1
      Thumb Down

      The position sensors showed continental drift

      during the period of the experiment, with a glitch when there was an earthquake, according to a popular report I read.

      I think it is possible that the experimenters devoted some thought to how far apart they were.

      They are now looking for _non_-obvious "hmm that's odds".

  14. Tom 7 Silver badge

    How do they know

    WHEN the neutrino set off?

    It sounds like a glib question but I don’t think this has actually been tested before - or if it has I cant afford to find the papers my taxes have paid for.

    1. Tim Starling

      Re: How do they know

      When a pion or kaon decays it produces both a muon and a neutrino. They detect the muons, and infer from the time of the muon detection the time at which the neutrino would have been generated. The original paper is available for free and has some pretty pictures showing the whole process:

  15. amanfromearth

    We don't serve your kind in here says the barman.

    A Neutrino goes into a bar.

  16. Wize

    Surely the only way to check this would be... send some in the opposite direction and check if the round trip time adds up to normal speed of light.

    Would mean building another super collider.

    We do have two of them on this planet. How about building a detector at each and playing neutrino pingpong?

    1. Anonymous Coward
      Anonymous Coward

      Or just...

      time some photons over the same route...

      1. Anonymous Coward
        Anonymous Coward

        time some photons over the same route...

        ... good luck with getting them through all that rock!

  17. Gusty O'Windflap

    this is all well and good...

    ... but will these neutrinos be able to do the Kessel run in less than 12 parsecs?

    1. This post has been deleted by its author

  18. Jim Carter

    When they find an explanation

    And I'm sure they will, I'm thinking I'll be just that tiny bit disappointed.

    Oh well, back to the Einstein-Rosenberg bridge...

  19. Anonymous Coward
    Anonymous Coward

    They need to drill a small tunnel between the two parts of the experiment and then measure how long a photon takes to travel the distance.

    1. Ken Hagan Gold badge

      That small tunnel would be about 10km below the earth's surface at its mid-point. (Oh, and around 730km long.) That's around 3 times deeper than the deepest mine in the world.

  20. Mips

    There is another solution

    When I was learning about electrical energy it took a considerable suspension of belief to be told that whilst current went down the wire and voltage appeared across the terminals of a resistor the power that appeared in the resistor came in at right angles on the Poynting vector. Through space! Of course in those days we only had 4 dimensions to deal with, now with substantially more branes it is a lot easier to explain. That things can act through dimensions which are not visible.

    Another puzzling thing which I have not seen explained is the suspension of Relativity at the Big Bang: the inflation from a singularity to the condensation of matter to form the early universe in 10e-15 seconds. How is it possible for matter to move as much as 15billion light years in this time? The only explanation I can determine is that in a singularity gravity is so great that space and time have no meaning, that the expansion does not so much involve physical movement so much as the expression of time and space to what is already in place: that what appeared to be a singularity was actually large but that space and time did not yet exist. Time may be more flexible than appears. Neutrinos may defy light speed.

    Another similar thought is that the proto particle soup is non-relativistic and not bound to travel in a 4 dimensional space time continuum. In these circumstances do neutrinos travel in the real world?

    1. Michael H.F. Wilkinson Silver badge

      According to inflation theory

      it was space that moved faster than the speed of light. This is perfectly allowable according to relativity. It is hard to get your mind around, I agree.

  21. lawndart


    It was probably all caused by an accidental mouse gesture anyway.

  22. This post has been deleted by its author

  23. The Man

    I've always noted that mathmatcially in E=mc^2 that c doesn't actually have to be a real number it could be a multiple of the imaginary number, i, and what on Earth (pun intended) does that mean if the total universe's E is a constant? Is E= m1c^2 + m2(ci)^2 actually helpful (the dark matter conundrum springs to mind here as m2 being negative in this case would reduce the 'observable net universe's mass')

    At which point I decide to get back to Call of Duty and not worry about relativity effects on my assault rifle bullets trajectory as I doubt it's been properly modelled by Treyarch...

    1. John G Imrie

      Call of duty

      not worry about relativity effects on my assault rifle bullets trajectory as I doubt it's been properly modelled by Treyarch.

      I bet it has, as there has to be *some* reason the apposing sniper kills me just before I pull the trigger.

    2. Anonymous Coward
      Anonymous Coward

      For starters, it's not E=mc^2.

      It's E^2=m^2c^4 + p^2c^2 where m is the rest mass, p is the momentum, and c is the speed of light.

      Since a photon has zero rest mass, the energy of a photon is E = pc = hc/L where h is Planck's constant and L is the photon's wavelength.

  24. Dom 3

    @Tom 7

    "How do they know

    WHEN the neutrino set off?"

    They don't, really. They know when the initial bunch of *neutrons* hit the graphite block at the beginning of the neutrino generation process. Then they time when the resultant neutrinos arrive at the other end. Then they calculate and / or measure how long the timing equipment and so on takes to do its thing, add in the expected time of flight, and finally find that there is a discrepancy. One possible explanation is superluminal travel by the neutrinos. Another is that their clocks aren't actually synchronised (as in this article). Another is that they've really badly ballsed up on measuring the response times of their measurement kit. Yet another is that the *decay* process exhibits some sort of superluminal behaviour alongst quantum tunneling lines. That'd be New Physics, for sure, but not quite as revolutionary as superluminal neutrinos. Yet another is that it's actually neutrinos that travel at the speed of light, as light itself gets bogged down by pesky virtual particles: for more on that. That's my idea...

  25. Anonymous Coward
    Anonymous Coward

    Gravity + Naïvety

    Slightly off-topic but if distant galaxies are said to be accelerating where did the accelerating forces come from? - and more interestingly, just how far out goes gravity extend and how did it get there before everything else?

  26. Mike Schwab

    Mike Schwab

    Note that the Neutrinos that DO NOT change flavor arrive *AT* the speed of light.

    Note that the Neutrinos that DO change flavor arrive 1 PLANK LENGTH earlier.

    This is due to involved in the flavor change.

    The new flavor leave the area of the change at the same time as the old flavor arrives at the area of the change, and it is one plank length long.

  27. Anonymous Coward

    Moving Earth?

    Has anyone allowed for the fact that the Earth itself is moving through absolute space, as well as rotating? I understand that this is quite a large number...

  28. Astrophysicist

    Martim Lapa

    Dear Sirs

    It is only true that general relativity is one of the greatest achivements of man's mind, it understands elegant mathematics, and let's not forget the non-simetric field relativistic equations that are featured in the fabulous "The meaning of relativity", with its outstanding mathematical language based in Ricci, Levi-Civita, Bianchi and Kronecker tensor calculus, Does anything can travel faster then light, when one says this, one has to have a powerfull mathematical expression to prove it, factual stating is not enough, and that wasn't made so far, it is therefore needed to create concepts of space beyond outer space, and have the necessary mathematical device to prove it, but if Einstein said with very powerfull mathematical arguments that nothing could travel faster then light, virttually very few people could prove it mathematicly otherwise, it is left for our imagination if that is possible, but it can only be sofismatic as we have to have strong scientific arguments to prove it.

    M.Lapa/Paul Rose

    1. amanfromearth

      Well, no

      Theorise all you wish, but the only real proof is experiment.

      It's the function of theorists to make theories to explain experimental results, not the other way round.

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