Faster than the speed of light

So. A respected experimental group, doing respected work, the OPERA neutrino experiment at Grand Sasso in Italy, have reported a startling result; they have measured a velocity for neutrinos that is in excess of the speed of light (a fractional increase of about of 1 in 100,000). The result is getting a huge amount of publicity because it appears to be in conflict with Einstein’s theory of relativity. ‘Einstein wrong‘ always makes headlines. I’m certainly getting a lot of calls and emails on the subject, not least because I had an article on relativity in Thursday’s Irish Times (see here).

In the OPERA experiment, a beam of neutrinos travels underground from CERN travel to Gran Sasso in Italy

The OPERA paper has been posted on the ArXiv here. Most physicists (including the participants) are calling the result an ‘anomaly’ and expect to find a hidden error, for two reasons

1. Thousands and thousands of experiments on elementary particles suggest that the speed of light represents a natural speed limit for material bodies, no matter how much energy you whack them with

2. There are deep mathematical reasons for believing that the speed of light in vacuum represents an absolute limit, from arguments of symmetry to the principle of least action. Basically, all sorts of mathematics suggests that the speed of photons- massless particles –  is the highest speed achievable. In addition, the principle underlies a great deal of observed physics, far beyond the remit of relativity.

So what is going on?

Science is a skeptical activity and scientists are slow to throw out a successful theory at the first sign of trouble -especially a theory as successful and as central as special relativity. Most scientists adopt a ‘wait and see’ approach when an experiment like this is reported.

For example, we know a great deal more about relativity than we do about neutrinos. It is only a few years since it was discovered that neutrinos have mass, and the phenomenon of neutrino oscillation – the transformation of one type of neutrino to another – is still not well understood. So it is possible that this experiment is an artefact of some unknown neutrino process.

A more prosaic possibility is that there is a systematic error in the extremely precise time/distance measurements necessary for the experiment. For example, the time of flight of the neutrinos is measured using a sophisticated version of GPS – perhaps there is a hitherto undetected error lurking in this method that is affecting the measurement. A few years ago, it was discovered that the moon has an effect on the curvature of the LHC tunnel, as does the TGV arriving at Geneva – these effects only show up because of the unprecedented precision involved in the experiments.

Finally, it is always possible that this result may turn out to be a real effect. In this case, we could be looking at some exciting new physics; not a violation of relativity, but the first evidence of hidden dimensions. String theorists have long mooted the possibility that the three familiar three dimensions of space may be accompanied by other dimensions, tiny ones that are curled up so that they are undetectable at normal energies. In principle, a particle that takes a shortcut through such a dimension could arrive early! This may sound like a rather fantastic explanation, but it is possible that an experiment at the unprecedented energy and precision of OPERA could see this effect for the first time. Certainly, it would not contradict any previous theory or experiment.

So an exciting wait, but my money is on a systematic error in the measurement of distance or time

Technical note

I keep hearing in the media that ‘relativity forbids travelling at speeds faster than the speed of light in vacuum.’ Actually, it doesn’t, as Einstein was fond of pointing out. Special relativity suggests that it is impossible for  body to be accelerated from subluminal to superluminal speed. Thus particles that travel faster than light are possible in principle so long as they always travel at that speed (known as tachyons). However, such behaviour has implications for time (it would run backwards) and for causality, and is therefore thought unlikely. Also, no such particles have been observed  in five decades of experimentation in particle physics .

Last weekend, I was quoted (well misquoted) in The Irish Times, making the last point above; you can read it here, it’s quite a good article.

Update

If it is a systematic error, what could it be?  Looking at the paper, my own guess is that it is significant that the group do not measure the time-of-flight of individual neutrinos, but massive bunches of the particles. Essentially they measure the beginning and end of a bunch, and apply statistics to get the mean time. A messy enough procedure, considering the accuracy required..

Update II

I have a letter on the experiment in The Irish Times today, you can read it here

About these ads

31 Comments

Filed under Particle physics, Science and society

31 responses to “Faster than the speed of light

  1. John

    Dr. O’Raifeartaigh,
    In another one of your blog posts called “Refuting Einstein: a media controversy in Ireland” posted by you on the 12th of May 2011, you repeatedly shot me down for saying that Albert Einsteins theory of relativity was wrong. Even when i presented you with scientific evidence to show you where Francis Everitt had manipulated the results of his Gravity Probe B experiment, you still chose to ignore the evidence and you continued to defend both Special and General Relativity. You seem to do this a lot.

    In this particular case of this latest news story about neutrino’s travelling faster than light, i agree that this WILL turn out to be an anomaly in the end. Nobody will be able to replicate the result. But i’m glad it draws attention to the fact that Special and General Relativity might be wrong. Because they are wrong!! They are very wrong Dr. O’Raifeartaigh. Both SR and GR contain very large mathematical errors.

    John.

  2. cormac

    I wish you’d call me Cormac. And I haven’t shot anyone

    • John

      Cormac,
      I address you by your professional name as a mark of respect. You “earned” your doctorate through hard work, and i recognise that hard work and respect the things you say in your blog.

      John.

      • I answer here your last post because in it is not replay. You are talking about generalities but nothing concrete. Carezani solve the whole actual Flawed Paradigm with a New One that explain more experimental results than Newton-Einstein together. The solution found correcting the misundrstanding of Lorentz given equations applied to DECAY solve the terrible problem of the Standard Model showing that it is absolutely wrong. Solve the Principle of Equivalence, the Pioneer slowdown, the New Celestial Mechanics. etc., etc., etc., etc. What seem to me, I regret to tell you this is that you cannot grasp the concept of any of those papers. We konw the technic, maikinga critiques with generalities, which are absolutely void.
        Lucy Haye Ph. D.
        SAA’s representative.

    • Thanks for the “interesting Physics” but the Carezani’ is more than Physics, It is a complete New Paradigma in Physics-Cosmology in this Historical stept. I am sorry but I don’t understand “what solution.” The Carezami’s New Paradigm has almost solution for “””the actual HISTORICAL problems”””, NO a Universal Panace. Sooner or later will be replaced for another “New Paradigm” but this is coming back to the Galileo-Newton and the Scientists of the 19 century COMMON SENSE, NO the FANTASIA of the 21 century. Please try to be specific and if it is possible using my e-mail: It is easier to me.
      Lucy

      • John

        Lucy,
        I’m sorry, i should have elaborated on my statement about you not having “the solution”. Lucy let me state that more clearly. Autodynamics does not solve any of the current problems in modern physics or cosmology. Yes there are many problems in physics and cosmology but Ricardo Carezani was wrong and his theories don’t solve any of the problems. They don’t resolve the problems created by General Relativity or Special Relativity which both contain massive errors.

        Lucy the ultimate solution will unite the atomic world of physics and the massive things we see through telescopes. Carezani, or you for that matter, do not have the solution. Why am i so sure that your autodynamics theory is wrong Lucy? Because i’m sitting here looking at the solution right in front of me on my screen. When your looking at the solution to a problem, and the solution is clear, then this allows you to see where other people are going wrong.

        But Lucy i do commend you for exploring other possibilities that might solve some of the problems that exist today in physics.

        John.

  3. Beautiful. The Neutrino doesn’t exist as Carezani in his Autodynamics prove without any doubt but they measure the velocity of the Anti-Neutrino. A double fantasy!!!!!!
    http://autodynamicslborg.blogspot.com/2011/06/never-any-detector-detected-any.html
    Lucy Haye Ph. D.
    SAA’s representative.

    • John

      Lucy,
      I’m replying to your comment on September 29, 2011. Your right, this blog doesn’t allow you to make more than 1 reply to someone else’s comment.

      Anyway Lucy i do admire your resilience in chasing your autodynamics theory. I will say one thing about you, your very sure about your theory.

      But as i said Lucy, i disagree with your autodynamics theory but i do agree with you that special and general relativity are flawed. Lucy your welcome to discuss this will me through email if you want. My email – john37309 {[@]} hotmail dot com

      John.

  4. FOR ME DOESN’T DOUBT THAT THERE SOME TYPE OF ANTINEUTRINOS THAR RUN
    WITH SPEEDS GREATER THAN LIGHT SPEED.I THINK THAT THERE ARE OTHERS SPACETIMES GENERATED BY THE PROPRE BASE OF STR ,THAT PERMIT SPEEDS GREATERS THAN THE LIGHT,THE PROPER ASYMMETRY BETWEEN PARTICLES AND ANTIPARTICLES DOES DEMONSTRATE THAT THE SPACETIME IS SKEW.THEN THE PROPER CONSTANCE OF SPEED OF LIGHT IS DUE THE BREAKDOEN OF PARITY AND REVERSAL TIME(PT) OBSERVED IN EXPERIMENTS AS VIOLATION OF CP-BUT IN THE GLOBAL CPT ´IS CONSERVED.THE TIME DILATATION AND CONTRATION OF SPACE IS DUE THE VIOLATION OF PT,THAT TURN THE MEASUREMENT OF ISOTROPY OF THE SPEED OF LIGHT DOUBT.
    I THINK THAT THE CALCULATES OF SPINS BETWENEN PARTICLES INTO ANTIPARTICLES AND VICEVERSA,ARE THE DIFFERENCES OF ROTATIONS BETWEEN
    SPINS THAT CALCULATE THE VALUE CONSTANT AND LIMIT OF LIGHT SPEED FOR
    THE CONTINUOS SPACETIMES

  5. I THINK THAT THE STRINGS ARE DERIVED OF CONJUGATION OF PARTICLES AND ANTIPARTICLES THAT GENERATE THE SPACETIME.WITH IT THERE OTHERS SPACETIMES CONTINUOS SPACETIMES,IN EXTRADIMENSIONS,SUPERSYMMETRY.
    I THINK THAT THE TACHYONS OF SUDARSHANS AND OTHERS ARE CORRECT WITHOUT VIOLATE THE STR. AND THE INVARIANCE OF LORENTZ,IS GIVEN BY THE ORTHOCROUS AND ANTICHROUS GIVEN BY THE METRICS OF FEYNMAN-STUCKELBERG.
    MUST THE IS SOME HORIZON BEYOND EINSTEIN,THINK I.

  6. James

    There’s really nothing like relativity to get the nutters excited. All those pet theories they’ve had for years without bothering to learn the original in the first place. I am no expert, and so shouldn’t really speak, but if the the neutrinos are tachyons then what’s stopping them going faster? Faster than light by 1 in 100,100? Why not twice as fast or a hundred times as fast. Sounds like some kind of calibration error to me, unless neutrinos just don’t want to show off.

  7. cormac

    It is almost certainly a calibration error, James. My own guess is that, looking at the paper, it is significant that they do not measure the time-of-filght of individual neutrinos, but massive bunches of the particles, that have a beginning and end, and apply statistics to get the mean time. A messy enough procedure, considering the accuracy required..

  8. James

    I think it is fair to say that if this result is true it would be the biggest shake-up in physics in a hundred years. (Special relativity was published in 1905 – so over a hundred years).

    It would also be somewhat ironic if the LHC failed to find the Higgs or supersymmetry but we got this as a kind of sideshow spin-off.

    As anyone who has studied physics knows, there are lots of variables we can change in physics when we get results from experiment because no existing theory ties them all down – such as the masses of particles, the nature of the Higgs(s) if they exist, etc. But this is different, it’s about the fundamental nature of space and time. Not so easy to tweak. I know there are ways to do this, but it smacks of how relativity arrived in the first place with people trying to tweak the aether theory to fit experiment.

  9. Hi Cormac

    It is great to see physics in the news again. No such thing as bad publicity and all that. It is annoying that we hear the usual sensational headlines of Einstein was wrong etc. As you already pointed out he never ruled out particles that could indeed travel at superluminal speeds.

    Neutrinos are a tricky particle, we have only just begun to understand its nature so it is no surprise that it had thrown up some odd results. My own believe it that some systematic error has crept into the data. Even a tiny error in the gps data would easily yield this magnitude of an error. Also as you pointed out we are dealing with statistical events to determine the speed of the particles not individual particle speeds.

    Should this experiment hold up to the scientific communities rigorous examination it will be a very interesting time in the arena of particle physics. As it appears we are closing in on the Higgs Boson and once the LHC is at its maximum operational power we should get our first tantalizing look at supersymmetry.

    I wonder what Cockcroft and Walton would think now seeing the likes of the LHC and all the work they started 70 years ago and where it has led us. Interesting times ahead.

  10. cormac

    Interesting points Micheal, and same for James. I’m not sure about the ‘no such thing as bad publicity’ angle though. After all the fuss of the last few days, if (when) a systematic error is announced, the overall impression will be that science changes its mind every few months or so…why trust any science when it might be overturned at any moment?
    I think science journalists could do a better job of getting the story whilst conveying the inherent skepticism of science

    • On the “no such thing as bad publicity” point this article in the WSJ highlights just how the scaremongering of why trust science works with point 5 (not that the other 4 points are any better). The author tries to use the above mentioned data in order to refute global warming

      http://online.wsj.com/article/SB10001424052970203388804576612620828387968.html#articleTabs%3Darticle

      5) The science is not settled, not by a long shot. Last month, scientists at CERN, the prestigious high-energy physics lab in Switzerland, reported that neutrinos might—repeat, might—travel faster than the speed of light. If serious scientists can question Einstein’s theory of relativity, then there must be room for debate about the workings and complexities of the Earth’s atmosphere.

  11. cormac

    Yup, exactly the problem. And in a few years time, journalists like this will be claiming that ‘scienitsts thought relativity was wrong in 2011′, whereas they themselves are the only ones who believe this story

  12. James Clarke

    Hi,
    I`m not a specialist in physics but I was thinking about the new results showing neutrinos travelling faster than the speed of light. It got me thinking. If light bends in the presence of a gravitational field then does it not slow down?.When the speed of light in a vaccum was measured, how can you be sure that earths gravitational field was taken into account.And if it was, what about the Sun, the Planets,the SuperMassive black hole at the centre of our Galaxy or even ripples in spacetime from far off objects. What if the speed of light in Vaccum in a Gallilean Space(ie far removed from everything so no gravitational fields) was different to speed of light in Vacuo here on Earth?Then, the neutrino would not have really broken the speed limit given by the lorentz transformation. (I dont know if I am talking crap or not, I dont have a doctorate and I`m only 16)
    ,
    James

  13. cormac

    Hi James, the answer to that conundrum is that it is really the velocity of light we should be talking about – speed with direction. A gravitational field effects the direction of lightspeed, but not the magnitude of the speed

    • Don’t try to explain a fanrasy, the Neutrino, which doesn’t exist with another different fantasy.
      See please why the Neutrino is a simple invention by Pauli because the SR’s equation are NOT applicable for DECAY. Why is Pauli Wrong? For Layman
      http://autodynamicslborg.blogspot.com/2011/10/why-is-pauli-wrong-for-layman.html
      Never any Detector Detected any Neutrino
      http://autodynamicslborg.blogspot.com/2011/06/never-any-detector-detected-any.html

      Lucy Haye Ph. D.
      SAA’s representative

    • James

      In the theory of relativity did Einstein not state that “According to the general theory of relativity, the law of the constancy of light in vacuo, which constitutes one of the 2 fundamental assumptions in the special theory of relativity and to which we have all frequently referred, cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation varies with position.” “We can only conclude that the special theory of relativity cannot claim an unlimited domain of validity;its results hold only so long as we are able to disregard the influences of gravitational fields on the phenomena(e.g. of light).”

      Could we not treat a gravitational field as a denser medium?(I don`t know if that is true as light bends curvilinearly and not like when it passes through glass.)

      • What you are discussing is irrelevant. The Light Velocity Constancy in Vacuum is an experimental value. If you want to know the truth on Special and General Relativity, please, go to:
        http://autodynamicslborg.blogspot.com/

        Lucy Haye Ph. D.
        SAA’s representative.

      • James

        But gravity does have an effect on light. It has been observed. Light is constant when a gravitational field is non-existent. When it is, the velocity changes as the light moves.The velocity of light here on earth is not the same as in empty space because light does not bend there. If this particle broke the speed of light, it has only broken the speed of light measured in a vaccum on earth.If we chopped the earth into equal squares, the curves would be the same(except the poles).Hence.light appears to be constant.If I am wrong,then what if the wave of this particle did not convey any information or the mass of this particle was constant.

      • You are very confuse. The light velocity is a Universal Constant even though the Gravity is Universal.
        Gravity could change it Energy, that is, its frecuency, but no its velocity, Could blend it but without changing the velocity.

        Lucy Haye.

      • James

        Thanks I understand now.

  14. Don

    Hi Cormac,
    I’ve only just seen your blog. Looks really good. The OPERA results seem to have stirred up quite a few off-the-wall theories going by the comments to your post! It’s always good to witness such ingenuity but I think I can sum up the sentiment of the majority of people in science including your good self I think- always try for the most prosaic solution first! To date I’ve seen just a couple of possible ‘prosaic explanations’ for the anomaly found: (1) is to do with the distribution of the neutrinos detected. The assumption is that the distribution of the neutrinos is the same as the distribution of the protons which they collided to form them. Now this might be ok but since so (relatively) few neutrinos are detected, it’s possible that those neutrinos are from the tail of the original distribution which would introduce a fairly substantial error. As I understand it the error is at the level of 10s of centimetres whereas the size of the detector is 10s of metres. (2) which you hinted at is to do with the time measurement. A recent paper by Contaldi of Imperial College spoke about how neglecting the synchronisation of the clocks could lead to an error of up to 20ns (the reported anomaly is around 30 ns). This is not the usual GPS systematic which the OPERA team have spent a good bit of time trying to nail down. It’s to do with the fact that in order to make sure the measurement is in sync, the clocks sending out the pulse and receiving the pulse must be syncronised. To do this they must be synchronised in the same place and then transported. In the act of transporting the clock extra errors are incurred. These are time of flight type errors. It’s similar to the integrated sachs wolfe effect in cosmology.

    Aside from these I’ve not seen any other compelling argument. What’s your take on the possible explanations – here and otherwise?

  15. ‘relativity forbids travelling at speeds faster than the speed of light in vacuum.’ Actually, it doesn’t, as Einstein was fond of pointing out.

    I was just wondering where Einstein pointed this out?

  16. i think that only not the neutrinos travel that the speed of light,but the proper speed of light ois not constant in vacuum.i belive that the asymmetry between the between particles and antiparticles does the speed of light appear as constant and limit,but the differences of spins is linked to asymmetry of space and time.that breakdown of symmetry betwenn left-right handeness spins-is that gives the metrics of spacetime continuos.
    the speed of light is not constant and limit by the proper nature,but due to symmetry symmetry.the proper relativity of motion that turn variable space and time,with the change of velocity in inertial system,is derived of breakdown of symmetry linked to the structures of space and time.then the antipaticles appear as particles traveling backward in time is due to the relativity of motion doing time dilatation and contraction of space,doing speed of light appear as isotropic,and invariants to the inertial systenms.this is due the diferences de helicity,that appear of breakdown of pt,that does connect space and time in spacetime continuos-each extradimensions of spacetime-containg a constant value for speed of light.
    the curvatures of spacetimes are associated to these extradimensions.and the time is given matematically by two-dimensions,this the time is potential in “future” and “past”,encurving the 3-dimensions of space.then that symmetry breaking connect space and time in spacetime metrics,through biquaternions in and noncommutative noneuclidean geometry
    then speeds greatest that speed of light are possible,but as future and past appear as processes to connections,then the superluminal signals is not violate causality ,globally,but only local

  17. there are differents types of background,then these changes in the background of the universe -topological changes-permit the existence of superluminal,without violate the causality.i believe that through of symmetry breaking as the violation of pt,cp,but the conservation to stronger interaction remain valids.then the axions would be deformation of the spacetime scenary.then the space deformed by the time-through pt broken,generate the dimension time with two opposite orientations that encurve the space,in spacetime continuos ,thence the lorentz’s invariance appear as property of STR,associated to the lorentz’s anti-ortochrous,that are due the asymmetry between left-right handness spins.thse differences-as the violation of cp-are compensates by the
    time dilatation and space contraction given both lorentz’s transformations

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s