Feb 27 2012

FTL Neutrinos? Einstein Can Rest Easy

Last September the OPERA collaboration in Italy announced that they had detected neutrinos apparently traveling faster than the speed of light. In their experimental setup the neutrinos arrived about 60 nanoseconds ahead of what the speed of light would have produced. The first persons to be skeptical of this result were the researchers themselves. They understood that this result is at odds with perhaps the most confirmed theories in all of science – Einstein’s theories of special and general relativity. According to relativity theory nothing can travel faster than the speed of light in a vacuum. This is not a practical limitation, it is inherent to the fabric of the universe.

Every now and then a lab somewhere claims to have broken this law of relativity, but in every case (so far) it seems that they simply made an experimental error or interpreted their results incorrectly. This ultimate speed limit seems to be as solid a law of physics as the conservation of energy, and experiments that seem to break this law suffer the same fate as those who believe they have invented a perpetual motion or free energy machine.

This claim, however, was different because the scientists exhaustively searched for any possible source of error they could think of and eliminated it, and the 60 nanosecond discrepancy persisted. Only when they did everything they could to disprove their results did they announce them to the world – still with the proper caution that was due. They essentially asked the rest of the scientific community to help them find the source of the error, while tentatively saying that if their results are true, wouldn’t that be interesting.

The claim was met by the scientific community with the proper skepticism. Most scientists did not believe the results and were confident that the source of error would be found. Some cited the fact that light and neutrinos from very distant supernova arrive at the earth at almost the same time (relatively) and therefore neutrinos must be traveling at the speed of light. True – unless the experimental neutrinos act differently because they are at a different energy level. This is not a convincing argument, but is theoretically possible. The general thinking was this – what is more likely, that the laws of physics have been overturned, or that this very complicated experimental setup has some minor source of error that is yet to be detected?

The response of the media was mixed, as you might expect. Many articles included the proper scientific skeptical response, but many also emphasized the amazing results. Anecdotally I encountered people in the public who only took from this story that something was found to travel faster than the speed of light, so Einstein was wrong, and that proves that scientists don’t really know what they are talking about, so whatever crazy theory they happen to prefer may be true also.

I joined the majority of scientists and skeptics who were confident that some source of experimental error would be found (which is just playing the odds). It would be fascinating and a huge science story if it turned out to be correct, but just terribly unlikely.

It is therefore not surprising that the apparent source of error has now come to light. According to the AAAS: 

According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos’ flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis.

Even in this scientists are being properly cautious. This is a potential explanation for the neutrino anomaly, but it needs to be confirmed. It seems likely, however, given that this effect matches the 60 nanosecond discrepancy of the previous experiments.

I love this whole science news story. It is a great opportunity to teach the public how science really works. The original scientists were skeptical of their own results and did everything they could to find their own error. When they couldn’t, they published their results, but without grandiose claims of changing our understanding of the universe and overturning a century of physics. The scientific community met the claims with skepticism and immediately started suggesting possible sources of error, each one was investigated to see if it were actually true. Meanwhile the implications of the claim were discussed, to put them into the proper context of data that we already have. If this experiment is true, then how do we square that with previous observations and experiments?

Now, it seems, the anomaly has been resolved, but that has to be confirmed as well.

Science is a self-skeptical, self-corrective but messy process. It would be great for the public to have a greater appreciation for this, so that they can more easily smell pseudoscience when they encounter it.

22 responses so far

22 thoughts on “FTL Neutrinos? Einstein Can Rest Easy”

  1. Nikola says:

    Indeed, this is an excellent story to illustrate science and the low possibility of paradigm shifts.
    I was explaining to a friend a few weeks ago that I wouldn’t lose sleep over FTL neutrinos, at least not over this single experimental setup, considering how much established science it would overturn.
    Still, my friend had good arguments, and was hopeful that maybe we would learn something useful about neutrinos through this, even if they don’t turn out to be FTL.
    I was a bit of a joykill and stuck to my “experimental error” guns.

  2. nybgrus says:

    When the story broke I was hanging around the undergrad engineering labs a fair bit. I ran into a number of kids there who were wrapped up in the hype and lacked the skepticism. I even engaged a few in conversation about it and after essentially giving a 5 minute version of Dr. Novella’s post here, they would invariably quiet down and decide to wait quietly, while still thinking of the implications. Of course, these were 18 and 19 year old freshmen and sophomores, but even they saw the wisdom in a skeptical outlook when it was shown to them. And there is nothing wrong with thinking about the implications, however fanciful they may be. For myself, I didn’t even bother to think. I was that certain it would be an experimental error that the tiny chance it wasn’t didn’t warrant my CPU cycles to contemplate it. But at 19 I sure might have. Great way to get the scientific imagination going 😀

  3. SARA says:

    “Science is a self-skeptical, self-corrective but messy process.” Messy. People don’t like messy. It requires thinking. It requires holding two or more possibilities in your head without rending one as absolute. So when faced with messy people translate that to wrong.

    Too many people in the world see two answers – right and wrong, yes or no, black or white…
    They don’t see that its not about an absolute answer its about a process that leads to more knowledge and that even the incorrect information teaches. (as Nybgrus used this experiment)

  4. Ben says:

    You might be interested to find out that the “loose cable” results aren’t as simple as the press has documented.

    See this for more depth:

  5. sonic says:

    Nothing better than experiment to find what is going on.
    And you have to be careful the experiment is run right.
    Physicists are best at this sort of thing.

  6. mdstudent says:

    Great example of the scientific method at work.

    Cam enthusiasts should take note and stop declaring “CURE!” every time a plant extract manages to kill cancer cells is a test tube.

    Science isn’t easily impressed.

  7. cwfong says:

    Scientists (some if not all) are open to the remote possibility that neutrinos (if not some other particle) could exceed the limits of the speed of light. Nature’s laws are self regulated and highly probabilistic, and therefor not immutable to straying from their most proper path. There are also those in the know that speculate that the limits to the speed of light might well have changed since the birth of this presently observable universe.

  8. cjablonski says:

    @cwfong: On the surface, your comments appear to be in favor of science, but there is an undercurrent of antiscience there as well. I would say most scientists are indeed open to the possibility that the speed of light is not the ultimate speed limit; however, they do so in the context that the overwhelming majority of observations support Einstein’s equations, and it would require extraordinary evidence before they would even begin to consider overturning them.

    Likewise, your statement about “those in the know” is vague and is evocative of fringey, cranky ideas.

    The point of the neutrino event and the media’s portrayal of it is that rational, thorough science prevailed—not rampant speculation and the idea that everything we know about the universe can be overturned by a single experiment.

  9. cwfong says:

    Those in the know are reputable cosmologists. And I noted this was speculative, didn’t I? My comments are entirely in favor of science, which includes a recognition of its philosophical basis.

  10. BillyJoe7 says:


    “fringey, cranky ideas”

    Not a crank, but certainly a fringe dweller and cranky about it! 😀

    (Note of caution: Unless you’re in there for the fun, I’m not sure that you should bother following up. Take my word for it, you’re not going to learn more from him than you learned from his first post :))

  11. cwfong says:

    I doubt that cJablonski is as ignorant as you are – that would be hard to beat – but because he was as quick to object to an unfamiliar hypotheses as you routinely are, you may have that knee jerk response in common. I suspect that when he reads the material, however, he will understand it, and you wouldn’t have a prayer in that regard.
    You have some value, however, as a subject in the study of the phenomenological nature of persistent ignorance.

  12. BillyJoe7 says:


    “he was as quick to object to an unfamiliar hypotheses (sic)”

    What friggin’ hypothesis.
    You have consistently refused to delineate it.
    How could cjablonski possibly have any idea what you are talking about.

    But he nevertheless picked you for a fringy crank, which is pretty good for a first read.
    He only got the order wrong:

    Cwrong, the cranky fringe-dweller.

  13. eiskrystal says:

    Meh, the voices in my head told me that they wouldn’t beat Einstein. I wasn’t the least bit surprised.

    Always listen to the voices!

    ….the voices….

  14. Kawarthajon says:

    I watched the conference in which they announced the FTL results of their experiments. I have to say that I was thoroughly impressed by the scientists’ presentation. They did not emphasize the FTL results, but emphasized their many attempts to find errors in their work. They appeared to be scratching their heads, wondering what happened for them to get this result. They put their results out to the world, asking other researchers to help them find out what went wrong or if their results held true. This was an example of real science and scepticism at work in tandem and I applaud the scientists’ approach to this problem, media coverage notwithstanding. It is a great story and I can’t wait to hear how it turns out. Hopefully they will get results without the loose cable and have more to talk about soon.

  15. cwfong says:

    BJ7 squawks:
    “How could cjablonski possibly have any idea what you are talking about.”

    He seemed to know something about the subject, whereas you seem to know nothing and seem to assume everyone has to be as abysmally ignorant as you are.

  16. cwfong says:

    BJ7, this “friggen’ hypothesis” about the early speed of light should fry what’s left of your brain:

    You skipped over that reference as usual.

  17. cjablonski says:

    Thanks cwfong, this is pretty interesting, and I’ll be a bit more cautious in my characterizations in the future.

  18. BillyJoe7 says:

    I was talking about your alternative to the modern synthesis/neoDarwinism.
    I didn’t need to click on your link because I read that article when it came out in the middle of last year. No big deal.

  19. cwfong says:

    What an evasive little bobber and weaver you are, BJ7. I made no reference on this post to the modern synthesis. And of course you now remember reading the article that you had no idea I was talking about when I cited it.

  20. BillyJoe7 says:

    Of course I did.
    Apparently you don’t understand side references.
    Oh well…

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