Faster than the speed of light?

I have been prompted to write this blog, instead of chilling with a glass of wine after a busy week and watching a movie on TV, because of the flurry of comments via email and Twitter that I have received today regarding the latest news from the Opera neutrino experiment.

It’s entirely my own fault. After the first announcement back in September I volunteered on Twitter, then on BBC television to eat my boxer shorts on live TV if this result is proven to be right. Now, many people mistakenly believe that this second repeated experiment is the confirmation needed for me to fetch the ketchup.

Let me begin by making two statements that I hope are very clear and that I can refer back to if necessary:

  1. The result from Opera is still only a measurement, not a discovery
  2. I would absolutely love it if it were true and particles could indeed travel faster than light. It’s heaven for physicists because it means the whole of modern physics is back up for grabs again. We would need something to replace Einstein’s theories of relativity or at least a way of fixing them.

OK, so, briefly, what is all the fuss about? Well, neutrinos are tiny elementary particles that are almost weightless and which pretty much ignore the presence of all other matter. We all have millions of neutrinos streaming through our bodies that arrive from space, mainly from the Sun. And they do this even at night because those neutrinos can pass right through the whole of the earth (when the sun is on the other side) before coming up through the ground, up our feet and leaving to continue through space. Now, neutrinos are so light that they are able to travel almost at the speed of light. We know there are three types of neutrinos (electron neutrinos, muon neutrinos and tau neutrinos). I won’t go into the technical details. Basically, the most common, the electron neutrinos are produced in what is known as beta decay inside the nuclei of atoms.

The Opera experiment involved timing a beam of mostly muon neutrinos between their point of origin at CERN in Geneva and the arrival point at a the Grand Sasso Lab in Italy (which has special detectors than can capture these elusive particles. The travel distance is 730 kilometers and the neutrinos appear to be able to cover this at a speed faster than light. Basically, they arrive 20 billionths of second sooner than light would were it travelling in a vacuum.  Of course, even though these neutrinos are travelling underground, it’s as though they are moving through empty space since they don’t interact or bump into anything.

Maximum speed limit

There is nothing that annoys people more about Einstein’s theory of relativity than its claim that nothing can travel faster than light. Why can we not conceive of anything moving at a speed of over a billion kilometres per hour? Granted, this is a stupendously high speed to which nothing that we know of (apart from subatomic particles) can get close, but special relativity seems to be saying that the laws of nature forbid anything from going faster.

This is hard to stomach if you haven’t followed the logical steps and the careful experimental tests of Einstein’s relativity. I do not plan to go through the details but will instead try and give a flavour of why physicists are so confident that there is a universal speed limit. You see in a sense it is not light that is so special that it holds the speed record, but rather that way space and time themselves are intertwined in our universe implies that there is a maximum speed limit beyond which those laws of physics break down. In our universe this speed happens to be 299,792,458 metres per second, or 186,282 miles per second. Light, because it has no mass, is able to travel at this speed. In fact, in the vacuum of empty space, light is unable to speed up or slow down but is constrained to always move at this speed.

There are a number of ways to explain why the speed of light is the upper speed possible in our universe. One method is by using algebra. (Oh great, you’re thinking, that will really convince me; a load of equations full of Greek symbols is just what is needed to put my mind at rest.) I will not go into all the gory details. Suffice it to say that, in special relativity, speeds get added up in a very strange way.

It also turns out that the faster an object moves the heavier it becomes, and the harder it gets to make it go even faster. The closer it gets to the speed of light, the larger its momentum becomes, but this is by virtue of its increasing mass, not its velocity. Consider what happens to an object’s mass when it moves very fast. The single most important consequence of the equations of special relativity is how mass and energy are related. Einstein showed that mass can be converted into energy and vice versa. The two are related through the equation E=mc2, which tells us how much energy is locked up in any given mass. The c stands for the speed of light, and thus the quantity c2 (the speed of light times itself) is a very large number indeed and explains how we can get so much energy out of a small amount of mass. This equation suggests that that we can think of mass as frozen energy.

Since a moving object also has energy due its motion (called its kinetic energy), its total energy will be the sum of the energy frozen as mass when it is not moving plus its kinetic energy. The faster it moves the more energy it has. This means that the real mass of an object will be due to its frozen energy plus the energy due to its motion. Most of the time the frozen energy of an object (its mass) is so much more than the energy of its motion that we can ignore the latter and take the mass to be constant. But as the speed approaches that of light the kinetic energy becomes so great it can exceed the frozen energy. Thus the mass of a fast moving object is much greater than its mass when stationary.

You can now see the problem of trying to attain light speed. Imagine an accelerating train engine pulling a single carriage. What if, for every ten kilometres per hour faster that it goes, another carriage is added. It would therefore have to work harder just to maintain its speed. The faster it goes the more carriages it has to pull, and the more power it needs. In the same way, the faster a body moves the heavier it will seem, and the harder it will be to make it go any faster. To accelerate it up to the speed of light would require an infinite amount of energy, which is impossible.

Finally, the real real real clincher is this: If anything can travel faster than light in our frame of reference, then we will always be able to find another frame of reference (i.e. another perspective from someone moving relative to us) in which it will appear to be moving backwards in time. Remember of course that if Einstein is right then all frames of reference are equally valid (all motion is relative). In this new frame, causality is  violated – that is, causes have to come before their effects, otherwise we are left with a paradox. For instance, if A were to shoot B with a faster than light bullet, then it will appear to some observers as though the bullet is moving backwards from B to A’s gun. That is B is shot before A pulls the trigger, so he could decide not to after B is shot!!

See how crazy violation of causality is, and just how much this neutrino experiment needs to explain away???

Could Einstein have been wrong?

Ultimately, the speed of light being the maximum speed limit is written into the fabric of reality itself. But what if we’re wrong? Is there a way of understanding this result? The simple answer is that we cannot with our current theories and understanding. We would need to overhaul the whole of modern physics, and we would need to find a way of explaining away the thousands of other experiments that over the past century have all confirmed that nothing can go faster than light. We may have to bring back the aether, or modify Einstein’s equations. We would have to explain why no other neutrino experiment showed such a result, and why none of the trillions of neutrinos coming from supernovae manage to exceed light speed.

So, yes of course Einstein could be wrong. The whole point of a scientific theory is that it is there to be shot down – to be shown to be false by new experimental evidence or to be replaced with a better, more accurate or more profound theory that explains more about the universe. But… extraordinary claims require extraordinary evidence, and Einstein’s ideas have been checked too carefully for too long for one experiment to come along and destroy all that. But of course that is all it would take if this experiment is proved correct.

Nobel prize winner, Sheldon Glashow, together with Andrew Cohen have predicted that such faster-than-light neutrinos would have to be radiating electrons and their antiparticles, positrons, all along their route from CERN to Grand Sasso via a process called vacuum Cerenkov radiation and hence lose energy. This is not seen. It’s a bit like an aircraft that manages to break the sound barrier silently and without a sonic boom. It just isn’t possible folks.

So, what would it take for it to be possible. I reckon there are two possibilities (there are other more exotic ones that are rather too speculative):

a)     Einstein was wrong and there is an aether: technically, what is known as Lorentz invariance is violated here and there is a preferred frame of reference.

b)    Einstein was wrong and Lorentz invariance has to be modified: technically, there may be nonlinear correction terms in the mass-energy relation.

I am not prepared yet to buy into these, or notions of tachyons (hypothetical faster than light particles), or wormholes as shortcuts through space-time or replacing the electroweak theory, etc. All this technical hot air basically means I prefer to appeal for now to Occam’s razor and go for the simplest explanation: there is still an error in the experiment.

So what could be wrong with the experiment?

I should say that this experiment is a highly complex one and has been carried out with the utmost care and attention to detail. I am a theoretical physicist not an experimentalist so I certainly refuse to insult my colleagues at CERN and Grand Sasso by trying to point out where they may have gone wrong. They know where uncertainties still lie. So far, they have ruled out one potential source of systematic error.

Not all the scientists involved in the experiment wanted to sign the paper because they were themselves yet to be convinced. After this second check, four of the physicists who had not signed the paper in September now agreed to sign it, but four more who had signed the first one now asked for their names to be removed from the new one.

Having said this, here are a few potential problems:

1. The neutrinos are produced via a complex process: protons from the SPS at CERN are fired in pulses at a carbon target, producing new particles: pions and kaons, which decay to produce muons and neutrinos. The muons are stopped in detectors while the neutrinos continue on to Italy. The start of their journey time is itself not recorded directly but is started from the timing of the proton beam and so the long process has to be subtracted away from total time to leave just neutrino’s travel time.

2. At both ends there are complicated electronics that may contain tiny systematic timing errors.

3. The timing has to be done via GPS satellite. We know that GPS systems only work if we carefully take into account Einstein’s theory of relativity. It seems strange to me that Einstein’s equations (both special and general relativity) need to be taken into account to measure something that is proving them wrong. It just doesn’t make sense. In any case, the experimenters haven’t ruled out an error in the GPS relativistic timing.

What next?

The experiment needs to be re-run independently by other particle physics laboratories, and plans are currently underway for this to take place in Japan and the US, but it will take some months at least.

I am happy to eat my boxers on live TV. It would be a small price to pay for the thrill of so much new physics. But let’s not be too hasty just yet, eh?

About Jim Al-Khalili

Professor of theoretical physics at the University of Surrey, author and broadcaster.
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88 Responses to Faster than the speed of light?

  1. Pingback: Still Faster-Than-Light Neutrinos? | Richer Ramblings

  2. Jim Spinner says:

    Potential problem 3 struck me as well, can’t have it both ways right!
    The Cerenkov radiation issue is interesting, not seen that mentioned before.
    Isn’t the distance corresponding to the timing discrepancy about the same as the size/length of the target, are we less sure of the mechanism of pion kaon production than special relativity?
    Jim

    • Will says:

      I’m not sure that potential problem 3 is such an issue; it just confirms that any replacement theory would have to encompass all the existing experimental support for Einstein’s relativity.

  3. phayes says:

    All this “FTL neutrino implies SR is wrong and causality is broken” nonsense I’ve been subjected to is extremely annoying. http://www.guardian.co.uk/discussion/comment-permalink/13051532 ;-)

  4. J Potter-Moore says:

    Chapeau Jim. Thanks for bringing the debate back down to Earth. The speed of light isn’t the maximum speed of light for the sake of satisfying some upper limit figure: it is at heart of the very definition of matter-energy conversion. You may even leave aside Einstein’s theory of relativity. It is his equation E=mc^2 that matters in this instance. Funny we tend to forget that the great man graced science and humanity with this equation well before the mathematisation of relativity (with the help of Mankowski). Is any one suggesting that “energy” should be ruled out of neutrinos or vice versa? Come on.

  5. yo says:

    I have a doubt.
    Why the “speed limit” must be the speed of light and not a slightly different speed, (speed of neutrinos, for instance)?

    • frank says:

      This is because the particles of light, photons, are massless. Since they have no mass, they move through space as fast as possible, and experience no time.

      Neutrinos, on the other hand, do have mass, so they cannnot (should not) move as fast as their no-mass cousins.

  6. Lawrence D’Oliveiro says:

    Assuming Einstein’s equations are right in order to prove them wrong is just standard practice for a “reductio ad absurdum” argument, is it not?

    Oh, by the way, “koans” ≠ “kaons”. :)

    • Sara G says:

      Although since a koan is a Buddhist paradox designed to show the limitations of logical reasoning and provoke enlightenment, they do have some similarities.

  7. Ehsan says:

    Well explained prof. can’t wait for the result of independent experiments in US and/or Japan. If such a thing turn out true, I think results from LHC experiments would be entirely useless until a physics is re-written.
    one question though:
    Would it be possible the laws of nature change as time passes by?

    Ehsan

    • theophilus mkhutyukelwa says:

      so far and at this point, nothing to raise eyebrows about. A lot still needs to be done to bring down what Einstein left for us. Thanks Prof, I’m completely convinced!

    • Martin says:

      The possibility of our laws of physics changing with time would be an interesting concept to ponder. If this were true then physicists would likely begin studying the laws of these changes instead of just physics at the present, such that they can prepare for the physics that are yet to come.

      I’m sure there’s an awesome sci-fi novel in there. :)

      • Sara G says:

        The universal constants have been suggested to have changed over time in the book13 things that don’t make sense (totally non-fiction) which I strongly recommend. It cites results of a natural nuclear reactor from Africa millions of years ago and light from stars to suggest that the weak force (if I remember correctly) has changed over time.

    • ricardo says:

      bueno, si así fuera no habría manera de hacer ciencia, pues los experimentos no serian falseables, el experimiento que un investigador hiciera hoy no podría ser compobrado por otro experimentador mañana… esta es la base de la homogeneidad en el tiempo de la
      que deben gozar las leyes de la física.

  8. hw looi says:

    If the scientists are right that neutrinos are faster than light, then contrary to what most experts believe in, neutrinos do not have any mass. And since they do not interact or interact as strongly as photons to the numerous types of particles, antiparticles, matter, dark matter, virtual particles and gravity in a vacuum, they are not slowed down by these entities as in the case of light. Therefore they should be able to move faster than light. The C in Einstein’s equation should be the speed of neutrinos in a vacuum!
    Actually, the particle or entitiy that has no mass, no charge and absolutely do not react or interact with anything in this universe should hold the ultimate speed record. Unfortunately, it is by definition impossible to detect.

    Alternatively, if neutrinos do have a tiny mass, then the speed of light in an absolute vacuum where there are none of those numerous types of energy, particles, matter, gravity etc. is in fact much higher than the 300,006 km/sec of the speed of the measured neutrinos. In other words, C > 300,006 km/sec and the neutrinos have not exceeded the real unimpeded speed of light. The speed of light that we have been measuring is not the maximum speed that light is capable of if it is not slowed down by the numerous “things” that really exist in a so called vacuum.

    For instance if we were to imagine that we all live in a block of glass, and if we were to measure the speed of light, we would find that the speed is only 70% of the present accepted value of the speed of light in a vacuum and that of neutrinos which are not slowed down by the glass atoms will still be at 300,006 km/s.

    • Jim Spinner says:

      Light doesn’t always travel at the same speed, true, that’s how lenses work.
      And actually particles can travel faster than light, if the light is slowed down, lie in water, that’s how Cerekov radiation comes about.
      I don’t think you can just adjust the maximum speed in special relativity, replace c by some other slightly larger value, and be consistent, the speed limit has that value and light must necessarily travel at that speed in a vacuum.
      Jim

      • Jim Spinner says:

        Sorry, should read. “like in water”
        Jim

      • phayes says:

        “I don’t think you can just adjust the maximum speed in special relativity, replace c by some other slightly larger value, and be consistent, the speed limit has that value and light must necessarily travel at that speed in a vacuum.”

        That’s all very true – the invariant speed of SR is c etc. and nothing is ever going to change that – but, contrary to popular belief, SR isn’t necessarily a (local) theory of everything:

        http://arxiv.org/abs/gr-qc/0107091
        http://arxiv.org/abs/1005.1614

    • frank says:

      “the numerous types of particles, antiparticles, matter, dark matter, virtual particles and gravity in a vacuum”

      As far as I know, there are no particles/matter (anti-, dark, or normal) in a vacuum. Gravity is an attraction of masses, and since there is nothing with mass in a vacuum, there should also be no gravity. There are virtual particles, but from what I understand, they shouldnt affect the passing through of photons/neutrinos.

      As for massless neutrinos, observations of supernova 1987A indicate that neutrinos do have mass, and it is likely less than 16 eV. If neutrinos moved faster than photons, we would have measured the neutrinos much earlier than we did.

      • hw looi says:

        To be very frank, I do not think that any scientist has ever been able to created a perfect vacuum on planet earth that does not contain even a molecule or an atom of matter! This can only be created in the imagination. It is well known that a so-called perfect vacuum has an intrinsic vacuum impedence and what I am trying to say is that the impedence of neutrinos in a vacuum is less than that of photons in the vacuum and as such has a great advantange as far as speed is concerned. In fact if the vacuum impedence to a massless particle like a photon were zero, the speed would be infinity!

      • hw looi says:

        And I forgot to mention that the effects of the gravity in a vacuum come from the planets, stars and galaxies and not just from the minute amount of matter in the vacuum itself.
        If we assume that that the vacuum impedence of photons is 1 unit (the vacuum impedence of other electromagnetic forces = 376 ohms), then knowing the peculiar nature of neutrinos, the vacuum impedence of neutrinos is probably less than 1 unit and as such it has a great speed advantage.

  9. Dara Conlan says:

    Jim,

    I generally agree with you. As an engineer, I remain a little sceptical with the overall accuracy of the measurements. They are reporting a speed of 1.0000237 c (or faster by just 0.00246 % c).

    I do have a question, and I would be very interested in your thoughts and comments. With such a small relative difference in speed reported, how do we factor in Heisenberg’s Uncertainty principle ? I searched through the updated paper, and found no reference to Heisenberg.

    On a related issue (!!), I tend to liken this reported result with the amazingly close finish to the Melbourne Cup horse race earlier this month … The photo-finish appeared to show a “nose hair” between the first two horses, circa 1-2mm difference ! I reckoned that it should have been called a “dead heat”, because the apparent gap on the frame could be impacted by inter-frame uncertainty, or even a slight parallax error, but I digress :-)

  10. Miguel says:

    Get ready to eat those shorts…but it’s ok…google “edible underwear” and it will be a pleasure..lol!!

  11. Andrew Wood says:

    How is the distance that the neutrinos travel calculated? Is it a straight line between the 2 points? Do neutrinos have to follow curved space time or do they go directly from a to b?

    • Thomas54 says:

      “Do neutrinos have to follow curved space time or do they go directly from a to b?”

      If not via curved space-time, what route would be more direct?

      • Martin Kohn says:

        A straight line I guess. (but that can’t be the case because they would have to disappear from space-time and then re-appear at the other end).

  12. Mark Rodel says:

    I love the idea of carbon bombarded by protons giving off quanta of zen ;-)

  13. Nick McGivney says:

    What about that X Factor though? Helluva show. You guys see it last night?

  14. EM Comments says:

    Hi Jim

    Tiny typo in “2. At both ends there are complicated electronics that mat contain tiny systematic timing errors.”
    Should be “may contain”.

    Nice explanation.

    Why, if they can detect the neutrinos arriving, can they not detect them leaving by the same or similar means?

  15. erur says:

    This *cant* be right. Think of all the sci-fi that has to be re-done from FTL to FTN (Faster than Neutrinospeed).
    It just cant be done. hehe

    As i recall, gravity also travels at lightspeed. Maybe it’s worth to re-measure?

  16. This talk of light “travelling in a vacuum” departs from the fundamental standpoint of Faraday, Maxwell and (early) Einstein that space-filling fields are physical, as the formulation of Steven Weinberg, Logunov etc. of a real energy tensor for the gravitational field. Light travels not in a vacuum but in that field and waves in it, as well as in the electromagnetic (e-m) field.

    If neutrinos have mass, they would likewise be travelling in the gravitational field and they would Cherenkov radiate in that field. But if they are massless like ‘photons’, but not perturbations of the electromagnetic field, they would be perturbations of a third space-filling ‘neutrinic’field. As that has an energy density, it automatically enters Einstein’s equation (ie. the Einstein-Hilbert unified field equation).

    So physics can accommodate neutrinos faster-than-light without the drastic overthrow that Jim warns of – and in a way as Alice suspects (http://crisisinphysics.wordpress.com) that might force him to eat his boxers.

  17. Pingback: Neutrino fields get Jim’s boxer shorts in a twist | Crisis-in-Physics

  18. Pingback: Is it possible to travel faster than the speed of light in vacuum? - Quora

  19. Jay Levitt says:

    Typical. If I had a nickel for every time a theoretical physicist declined to eat his underwear on TV because of special relativity…

  20. Heim says:

    The sideffects of quantum entanglement have causal effects that are faster than light. Or not?

    Offtopic: Did someone hear about Burkhard Heim, what do you think about this person?
    Found http://www.heim-theory.com/

  21. Alleagra says:

    “The whole point of a scientific theory is that it is there to be shot down – to be shown to be false by new experimental evidence or to be replaced with a better, more accurate or more profound theory that explains more about the universe. ”

    Absolutely! Shame it doesn’t work out quite like that in the realm of climate science.

    • KG says:

      Well of course it would, if there were good evidence that the consensus on anthropogenic climate change was wrong. Unfortunately, there isn’t, and you and your fellow “sceptics” will eventually have to adapt to reality, rather than insisting that it conform to your prejudices. Even more unfortunately, you won’t be the only ones to suffer as a result of your stupidity.

  22. Pingback: Faster-than-light neutrinos observed again « Why Evolution Is True

  23. Lou Jost says:

    Can somebody help me with the apparent violation of causality mentioned by Jim? He said in some reference frames, a shooter firing a supraluminal bullet would appear to receive the bullet into his gun rather than emit it, and the shooter could change his mind about shooting after his victim drops dead, causing a paradox. But the causal chain involving free will only needs to apply in the shooter’s frame of reference. A spectator in a moving frame would look at the shooter and see nothing that violates any law of physics. I don’t see a true paradox, just something that we are not accustomed to.

    • phayes says:

      “But the causal chain involving free will only needs to apply in the shooter’s frame of reference.”

      The fact that it doesn’t necessarily is the paradox! Consider a similar example: A shoots B in one inertial frame with a superluminal bullet. In another inertial frame, C passes B at the moment of B’s demise and immediately shoots another superluminal bullet at A which reaches and kills A before A pulls/pulled the trigger. If you look at the spacetime diagram on page 12 of this you can see that such a paradoxical situation can be arranged if ‘hard’ superluminal motion is allowed.

  24. Abhay Kapoor says:

    I am not quite convinced with your A shoots B argument, where you said that A would be able to decide not to pull the trigger after he shot B.
    From what I understand, let A have a normal gun with a normal bullet (and not the one with speed of light) and say he is shooting B with it.
    Assume that A is looking at his hand pulling the trigger through a medium other than vacuum through which the speed of light is so slow that bullet can reach B faster than light travelling through this medium reaches A’s eyes.
    In this case again when A shoots, B would have been shot before A actually sees that he has pulled the trigger, but this does not mean that A can reverse his action. What we are only saying is that A comes to know of his action much later than it has already been done?
    (The same situation could also have been created if A were looking at the trigger being pulled through a streamed video which had some delay)
    I don’t see this as any violation of the laws of physics. Since the action has already been done there is no way to undo it. Yes, A came to know of it later but that’s all there’s to it.

  25. Grzegorz Maj says:

    This causality rule is really funny. Imagine that maximum speed of information is speed of sound. Then you are sitting in a trench and soldier next to you gets hit, after some time you hear gunshot. Omg causality rule is broken. B gets killed before A pulls the trigger. Can A change his mind after B is killed?

  26. Gwyllym says:

    Nothing in the universe is perfect, regardless of how we like to think. Einstein was a theoretical physicist not a god and he does not dictate the way the universe works, having said that, E=MC^2 may in reality turn out to be E=MC^2+1 for all we know. Without the benefit of experimental data at the time that was the best that he could do. I say the law still exists we just need to add the 1.
    Before we all shoot our mouths off, let another lab perform the experiment and get the data, only then will Jim need to get the soy sauce out.

  27. Pingback: One small step for super luminal neutrinos « Joy of Science

  28. Steve Jones says:

    Now what would happen if it was possible for a particle to have negative mass…

  29. Bob Lyons says:

    If these neutrinos are moving backwards through time, then perhaps we should call them oldtrinos. :-)

  30. Derek says:

    Jim, I think you should eat your boxers and if you are right and these results are flawed you can rest assure that no one will travel back from the future to stop you.

  31. John O'Reilly says:

    Hey Jim, how do you like your shorts cooked? Rare, medium, or well done?

  32. LenS says:

    Given that the timing side seems like it could be correct (atomic clocks, satellites etc) ,
    what about the accuracy of the distance measurement.
    I just wondered how did they estimate the straight line distance through the Earth rather than around the curvature of the Earth’s surface.
    I reckon about a 17.98 metres error would explain the speed anomaly.

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  37. Kieron says:

    I don’t have the maths or the engineering skills to make any rational comment on the paper, but I am loving watching all the alternatives being suggested to explain why they can’t be right

  38. Pingback: Update on the OPERA results. « Dub i nGal

  39. Some great replies to Jim’s wonderful explanation and opinion.
    Some very funny replies too eg. Bob Lyons ‘Oldtrinos’!
    I liked Steve Jone’s question..’ Now what would happen if it was possible for a particle to have negative mass…’.
    It’s certainly an interesting notion to contemplate this experimental data as being ‘correct’. In science nothing is ruled out or, closed to reinvestigation no matter the historical crowns of achievements.
    The ‘measurement problem’ here is so open to variations and unknown,s it’s a sure bet that it may manifest to explain the apparent ‘anomaly’. But… I hope not!
    I can’t wait to hear how further experimentations go and, the brilliant minds club together in trying to resolve this, if it’s an abnormal reading.
    I have my own theories but, they are only speculations.

  40. Aren’t some scientists in a quandary – The theories and practices they use are bound by laws which overtime generated a Earth bound Universal backbone. Now that something new arrives and has some potential for some in science the most important thing is to keep the status quo. Modern science should look beyond the curtain of Einstein and realise the vastness of what is not understood.

  41. Philip Pugh says:

    I have started a discussion on the BBC Sky at Night site:

    http://forum.skyatnightmagazine.com/tm.asp?m=126379&mpage=1&key=&#126393

    I think one POSSIBLE explanation is that the distance of 730km is true in a Euclidean sense but that the neutrinos are able to take a “short cut” through spatial dimensions higher than 3. I think other experiments may well produce similar results. We obviously can’t shine a light beam through solid rock but if we could I would expect it to be travelling “faster than the speed of light” because it would take the same short cut as the neutrinos.

    As I understand it, neutrinos have not been observed to travel faster than the speed of light in a vacuum because they are taking the same path.

    In the case of CERN it is not possible to verify which path light would take.

  42. Pingback: Improbable Research » Blog Archive » A shorts course in cooking, inspired by neutrinos

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  44. Pentcho Valev says:

    Jim Al-Khalili,

    Neutrinos may or may not have exceeded the speed of light and yet I am afraid you will have to eat your boxer shorts some day. Two experiments – that of Michelson-Morley and that of Pound-Rebka – show that the speed of light varies with v, the speed of the emitter relative to the observer, in accordance with the equation c’=c+v given by Newton’s emission theory of light:

    http://www.pitt.edu/~jdnorton/papers/companion.doc
    John Norton: “These efforts were long misled by an exaggeration of the importance of one experiment, the Michelson-Morley experiment, even though Einstein later had trouble recalling if he even knew of the experiment prior to his 1905 paper. This one experiment, in isolation, has little force. Its null result happened to be fully compatible with Newton’s own emission theory of light. Located in the context of late 19th century electrodynamics when ether-based, wave theories of light predominated, however, it presented a serious problem that exercised the greatest theoretician of the day.”

    http://philsci-archive.pitt.edu/1743/2/Norton.pdf
    John Norton: “In addition to his work as editor of the Einstein papers in finding source material, Stachel assembled the many small clues that reveal Einstein’s serious consideration of an emission theory of light; and he gave us the crucial insight that Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity. Even today, this point needs emphasis. The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE.”

    http://groups.google.com/group/sci.physics.relativity/msg/44abc7dbb30db6c2
    John Norton: “THE MICHELSON-MORLEY EXPERIMENT IS FULLY COMPATIBLE WITH AN EMISSION THEORY OF LIGHT THAT CONTRADICTS THE LIGHT POSTULATE.”
    Tom Roberts: “Sure. The fact that this one experiment is compatible with other theories does not refute relativity in any way. The full experimental record refutes most if not all emission theories, but not relativity.”
    Pentcho Valev: “THE POUND-REBKA EXPERIMENT IS FULLY COMPATIBLE WITH AN EMISSION THEORY OF LIGHT THAT CONTRADICTS THE LIGHT POSTULATE.”
    Tom Roberts: “Sure. But this experiment, too, does not refute relativity. The full experimental record refutes most if not all emission theories, but not relativity.”

    Of course, the epoch-making statement “But this experiment, too, does not refute relativity” needs a lot of discussion that for the moment is impossible in mainstream science. Still let me call your attention to the concept of “protective belt” advanced by Imre Lakatos:

    http://bertie.ccsu.edu/naturesci/PhilSci/Lakatos.html
    “Lakatos distinguished between two parts of a scientific theory: its “hard core” which contains its basic assumptions (or axioms, when set out formally and explicitly), and its “protective belt”, a surrounding defensive set of “ad hoc” (produced for the occasion) hypotheses. (…) In Lakatos’ model, we have to explicitly take into account the “ad hoc hypotheses” which serve as the protective belt. The protective belt serves to deflect “refuting” propositions from the core assumptions…”

    The protective belt (“contracting lengths, local time, or Lorentz transformations”) referred to by Banesh Hoffmann:

    http://www.amazon.com/Relativity-Its-Roots-Banesh-Hoffmann/dp/0486406768
    “Relativity and Its Roots” By Banesh Hoffmann: “Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton’s laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether.”

    Pentcho Valev pvalev@yahoo.com

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  46. donald penman says:

    Could it be that neutrinos travel a more direct route through a strong gravitational field than light? Neutrinos interact less with mass so the opposite might be true that mass and gravity interact less with neutrinos.

  47. Cres Huang says:

    This current faster-than-light fuss is overdue for decades if not century in my view as a beginner of physics.

    Consider these:

    1. An aircraft generates air disturbance continuously regardless of it’s speed.

    2. Sonic boom happens when air molecules are jammed and forced out of the way faster than speed of sound.

    3. There are no sound and sonic boom when space shuttle leaves the atmosphere, when no air molecules get in the way.

    4. There are no sound and sonic boom when the force of a traveling object is unable to act upon air molecules. Objects such as billions of super sonic neutrinos going from LHC to OPERA.

    Here are my questions:

    1. How faster-than-light neutrinos radiate electrons and their antiparticles, positrons? Neutrinos are supposed to be elementary particles, where do these particle radiations come from? Does this mean neutrinos encounter resistants, or neutrino fission? How to measure or detect these radiations? Can lead blocks at OPERA do the job?

    2. Are these radiations supposed to be generated by neutrinos throughout their journey regardless of speed?

    3. If there is noting gets in the way of neutrinos, how superluminal radiations are able to occur?

    LHC can only accelerate proton beams to near speed of light does not necessarily mean protons can not travel at or faster than speed of light. A vessel can only go as fast as it’s propulsion system. I don’t suppose Super Proton Synchrotron in LHC is able to provide thrust faster then the speed of light.

    This near light-speed energy of proton beam would pass on to much smaller neutrinos emitted from the collision. The explosion from the collision would releases a very large energy, relatively to the size of neutrinos. When this energy acts upon neutrinos, it could boot their speed past protons, hence very likely, past the speed of light.

    Neutrinos and lights from SN1987A traveled vast distance in unknown environment and variables. It is a single-unplanned event in uncontrollable environment. In my own option, the measurements of 3-hour-early-arrival neutrinos is more questionable, scientifically, than measurements from OPERA which is in better controlled environment and it has been repeated.

    • Cres Huang says:

      The last sentence in last second paragraph should be “it could boost their speed past protons, hence very likely, past the speed of light. “

  48. THEMADFIFER says:

    If you think of space on a multi-dimensional level then there is no distance between anything. If the Neutrino can pop out of our observed dimension then back in it could appear to have travelled faster than light. The inter-dimensional fabric I believe to be the Higgs field, which is comprised, actually made of Bosons particles and is a field at the same time, like the photon being a particle and a wave at the same time. On the other side of this field I think you will also find the missing anti-matter. The Neutrino at this speed can some times pop in and out, that is if it can make it back before being lost or destroyed by collision with anti-paticles. Could be wrong but until proven otherwise it’s my theory. :)

  49. THEMADFIFER says:

    Anyway. If light cannot escape a black hole then the gravitational wave/ particle? must be travelling faster than the speed of light. Then light on it’s way inside must become faster than the speed of light. If this is why the laws of physics break down then maybe this is what you are witnessing when trying to observe a black hole. You stop seeing it, just as might be said for the Neutrino, you dont see it, it’s popped out of our space time, a place where the known laws of physics do not apply. If two photons travelling at close to the speed of light collide would they not throw debris off travelling faster than the speed of light? If a photon is hit by another from the rear and to the side would this not propell it as seen in matter. I think it is possible and the speed limit is a cop out like infinity itself. Simply there to make the maths work.

  50. Jim says:

    causality is violated – that is, causes have to come before their effects, otherwise we are left with a paradox. For instance, if A were to shoot B with a faster than light bullet, then it will appear to some observers as though the bullet is moving backwards from B to A’s gun. That is B is shot before A pulls the trigger, so he could decide not to after B is shot!! If this is true, then we see light from the sun before it has left, since it travels at the speed of light. Perhaps the paradox is not the speed of light but time as we know it. Time is after all an abstract measurement of distance travelled by a planet.
    Remember the impossible is that which has not yet been proven possible, keep an open mind I’m sure Einstein did.

  51. looi hw says:

    Although I still feel that neutrinos can go faster than light because their vacuum impedance is less than that of light photons, here is another possibility that needs to be considered:

    What if I pretend that I am an innocent little boy who knows nothing much, but who thinks that neutrinos can go faster than light because neutrinos do not really exist as such, but are actually nothing more than just pulses of energy that is transmitted along an almost infinitely strong and rigid “needle” of length which varies from a few microns to billions of miles and which is incredibly thin.

    These “needles” could be made of stacks of Higgs Bosoms and fill up throughout the universe to form the so-called Higgs Field.

    Since the needles are almost infinitely stiff, if energy is applied to one end of these needles, the energy pulse (“neutrinos thus created”) would be transmitted almost instantly to the other end and if the other end is associated with an electron in the detector material, the energy would be converted into matter and appears as an electron neutrino. If the other end is associated with a muon or tau particle, the energy pulse (“neutrino”) would be converted into a muon or tau neutrino.

    If we have a bundle which is made up of these needles of varying lengths, and if we have “neutrino” detectors along the whole length of the bundle we will be detecting neutrinos of different types along the length of the bundle. This could explain why neutrinos appear to change flavours or oscillate as they move along. And this could also explain why neutrinos can pass though a large mass like planet earth as the earth is already being pierced by trillions upon trillions of these almost infinitely stiff needles that form the fabric of space.

  52. Muhammad.O.T says:

    Dear Mr Jim,
    Because of my theory ”particle energy”, no thing, particles especially, can travel faster than light.My theory can interpret all elementary forces that particles interact.It assume that photons have mass and it increases with photon energy.
    I am from Egypt and I live in Kuwait.My dream is to be a theoretical physicist.

  53. Muhammad.O.T says:

    I want to left your minds to notion that no one can belittle any particular theory in physics.This is a great mistake that you committed.

  54. hw looi says:

    Dear Professor Jim Al-Khalifi,

    If we believe that neutrinos do have a mass from the point of creation of the neutrino to the point of detection, as such they should react to gravity and would form an extremely dense layer of orbiting neutrinos around every black hole because of their immense speed and their superior numbers in this universe.
    I wonder if anyone has found such a layer of orbiting neutrinos around a black hole.

  55. Muhammad.O.T says:

    I want to set your minds to notion that no one can belittle any particular theory in physics. This is a great mistake that you committed

  56. hw looi says:

    In the vacuum of space, if there are two bodies A and B and if there is absolutely nothing between them they should come together. They must be some form of energy field that is keeping them apart. This energy field which keep the planets and stars apart could have been created during the big bang.
    And this same field may be the energy that is contributing to the impedance of the photons.

    Gravity could also be explained by assuming that any body with a mass will be capable of absorbing this field and creating a decreasing density of this field as we go further and further from this body

    So before the big bang since there is really absolutely nothing with no time and space, all virtual particles that are being continuously created out of nothing should come together and occupy the same point and as such would ultimately form a singularity with almost infinite density and triggers off the big bang.

    This could happen if there is a mechanism which separate these virtual particles from their anti-particles.
    So has anybody found such a mechanism?
    HW Looi
    email: looihw88@gmail.com

  57. hw looi says:

    Corrected Version of Comments:

    Dear Prof Jim,

    In the vacuum of space, if there are two bodies A and B and if there is absolutely nothing between them they should come together since there is nothing to keep them apart. They must be some form of energy field that creates the space to keep them apart. This energy field which keep the planets and stars apart could have been created during the big bang.
    And this same field may be the energy that is contributing to the impedance of the photons.

    Gravity could also be explained by assuming that any body with a mass will be capable of absorbing this field and creating a decreasing density of this field as we go nearer and nearer to this body.

    So before the big bang since there is really absolutely nothing, with no time and space, all virtual particles that are being continuously created out of nothing should come together and occupy the same point and as such would ultimately form a singularity with almost infinite density and triggers off the big bang.

    This could happen if there is a mechanism which separate these virtual particles from their anti-particles.
    So has anybody found such a mechanism?

    Dr HW Looi
    gmail: looihw88@gmail.com

  58. Quentin Brewster says:

    This is a great article, and a great topic to explore. Thanks for sharing. It is still should be carefully thought out! http://9pillsonline.com/

  59. bernard platt says:

    Professor Jim Al Khalili has presented documentrys which are educational, inspirational and entertaining. I hope there will be more soon.

  60. Angelo Molinaro
    I had an article published in the scientific journal titled Galilean Electrodynamics Volume 15 Number1 January/Feburary 2004 issue. The article was titled The Invariance of Mass, which proves mathematically that Mass is an invariant. This finding proves that we can travel faster than the speed of light. I also wrote a book titled The Two State Universe which describes this finding. The book also describes a new theory of the Universe and Gravity, and answere many of the unanswered questions of Science.
    I have an undergraduate degree from MIT, I also have a Doctor of Science degree in Electrical Engineering, and a Doctor of Philosophy degree in Theoretical Physics.

  61. bernard platt says:

    Photons are the same as electrons, they are packets of pure energy. They have no substance. Or have I got it wrong (again)

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