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Neutrinos Travel No Faster Than Light, Says ICARUS

Posted by Soulskill on from the do-you-know-why-i-pulled-you-over dept.

ananyo writes "Neutrinos obey nature's speed limit, according to new results from an Italian experiment. The finding, posted to the preprint server arXiv.org, contradicts a rival claim from the OPERA experiment that neutrinos could travel faster than the speed of light. ICARUS, located just a few meters from OPERA, clocked neutrinos traveling at the speed of light, and no faster, after monitoring a beam of neutrinos sent from CERN in late October and early November of last year. The neutrinos were packed into pulses just four nanoseconds long. That meant the timing could be measured far more accurately than the original OPERA measurement, which used ten microsecond pulses. The new findings are yet another blow to OPERA's results. Researchers there had announced possible timing problems with their original measurements. For many, this will pretty much be case closed."

18 of 112 comments (clear)

  1. Didn't they already find an equipment error? by Anonymous Coward · · Score: 4, Insightful

    I mean, what kind of a bozo looks at an unexpected result, from an incredibly complex first-one, never-been-done before kind of a machine, and jumps to the conclusion "FASTER THAN LIGHT"!

    I always assumes the faster than light shit wasn't an actual claim, just lazy reporters trying to hype up some attention and web clicks or what not.

    I'm curious that neutrinos went the speed of light at all. IIRC, don't neutrinos have mass? Shouldn't it be impossible for anything with mass to go c?

    1. Re:Didn't they already find an equipment error? by Goaway · · Score: 4, Informative

      Neutrinos do seem to have mass, and thus do not actually travel at the speed of light. However, the mass is very small (and as far as I know still unknown), which means that since they are created with fairly large energies, they immediately start moving at extremely close to the speed of light. So close that we can't tell the difference.

    2. Re:Didn't they already find an equipment error? by snowgirl · · Score: 4, Informative

      I'm curious that neutrinos went the speed of light at all. IIRC, don't neutrinos have mass?

      Yes, but it's very small. For example, while the electron has a mass of about 0.5 MeV, the neutrino upper-bound has been pushed down from 50 eV, down to the prediction that the combined mass of all flavors of neutrinos must be under 0.3 eV.

      So, it's around less than a millionth the mass of an electron. This means that it can obtain much faster speeds with the same amount of force.

      --
      WARNING! This girl exceeds the MAXIMUM SAFE standards established by the FDA for BRATTINESS
    3. Re:Didn't they already find an equipment error? by Kjella · · Score: 4, Interesting

      I always assumes the faster than light shit wasn't an actual claim, just lazy reporters trying to hype up some attention and web clicks or what not.

      Of course that was the claim, but in a sane science to layman translation it'd be: "We have this crazy result here with neutrinos that seem to go 60ns faster than light speed. Pretty much all of established science goes against this, but we've double checked our equipment and figures and can't find the error. So we're telling you about it so someone else can run this experiment and see if they get crazy results too, meanwhile we'll triple check our equipment and figures." There's not a single scientist surprised by this eventually being proven to be just a fluke. Nor by journalists hearing "blah blah blah neutrinos blah faster than light blah blah blah", lets make a headline. Absolutely par for the course, as far as science reporting is concerned.

      --
      Live today, because you never know what tomorrow brings
    4. Re:Didn't they already find an equipment error? by marcosdumay · · Score: 4, Insightful

      First, nobody (except for the press) claimed they saw faster than light neutrinos. You are right on that assumption. Opera basicaly said that they had an interesting result, and couldn't find where it was wrong, now, if anybody out there could help find the problem, they'd be glad.

      Second, Opera found a problem, corrected it, but will only be able to state with certainty that this problem was the cause of the faster than light neutrinos once they run the experiment again. That will take some time.

      Then, what you do when you get such an interesting result is to repeat the experiment. That is what was done here, and the result didn't repeat. That's science working the way it should, and the press working the way we all learned to expect.

      About your question, the neutrinos aren't moving at the speed of light. It is just that their mass is so small that we can't detect the difference between their speed and c.

      --
      Rethinking email
    5. Re:Didn't they already find an equipment error? by rrohbeck · · Score: 4, Informative

      It was mostly about metrology: "How could we have gotten this wrong?" They never raised the idea that Relativity might be wrong. The original paper was very clear and cautious about it.

      --
      thegodmovie.com - watch it
    6. Re:Didn't they already find an equipment error? by jfengel · · Score: 4, Informative

      Unfortunately, no. The neutrino oscillations tell us that mass must be present. That's the only way the mechanisms allow oscillations to happen at all. As long they can participate in mass interactions, they oscillate. But that's all we get out of it.

    7. Re:Didn't they already find an equipment error? by Kreigaffe · · Score: 4, Insightful

      Relativity has a body of proof behind it. One strange result MIGHT invalidate it, but it's more likely that were these results valid that we would've had a clue that this *could* happen before it happened. The right way to approach it is to assume relativity -- which has evidence backing it up, experimental and theoretical -- is correct, and that there was some experimental error, something systemic.

      Hey guys, this result doesn't agree with what we expected and believe true based on math and experiment. What did we do wrong?

      Likely, something was done wrong.

      In the unlikely case that nothing was done wrong and the results are reproducible, well.. THEN you start questioning relativity.

      --
      ... still waiting for this free-as-in-beer free beer I keep hearing about. :|
    8. Re:Didn't they already find an equipment error? by Obfuscant · · Score: 3, Informative

      You never say person A beat person B by 6 cm/s you say person A beat person B by 6 seconds.

      That's because the winners of races are based on time, not instantaneous or maximum speed. Drag races always spout speed data, but the winner is the one who crosses the finish line first, not necessarily fastest.

      "60 ns faster than the speed of light" is meaningless. "The neutrinos arrived 60ns sooner than they would have if they were travelling at c" isn't, as long as somewhere you could find out how far they went and then back out the speed they were going.

    9. Re:Didn't they already find an equipment error? by maugle · · Score: 3, Informative

      Last I checked, their mass was thought to be somewhere between 0.25 and 3 eV. Which is amazingly small, considering electrons weigh in at 0.5 MeV.

  2. "Another blow?" by Anonymous Coward · · Score: 5, Insightful

    People keep phrasing this like OPERA came out with a headline like "Neutrinos Travel Faster Than Light, and If You Disagree, You're a Stupid Doodyhead."

    That is not what happened. OPERA basically said "Hey, we have this anomalous result that we don't really think could be right, but we looked at all our stuff and couldn't find the problem. Please help us fix this. Thanks."

    1. Re:"Another blow?" by azalin · · Score: 4, Insightful

      People keep phrasing this like OPERA came out with a headline like "Neutrinos Travel Faster Than Light, and If You Disagree, You're a Stupid Doodyhead."

      That is not what happened. OPERA basically said "Hey, we have this anomalous result that we don't really think could be right, but we looked at all our stuff and couldn't find the problem. Please help us fix this. Thanks."

      Yeah but that does make a lousy headline, don't you think?

    2. Re:"Another blow?" by Sir_Sri · · Score: 5, Informative

      which neatly summarizes the difference between how science is actually done, and how the media, including apparently /. cover science.

      In real science when you do an experiment you just have results. You may not like the result, you may not want that to be the result, and you may think there is something wrong with the results. But that's what you did, that's what happened and if you can't figure out why the results are the way they are, well then you need the broader scientific community to help, and you write it all down in papers so that other people can learn from what happened to you.

    3. Re:"Another blow?" by chichilalescu · · Score: 4, Funny

      somewhere, in a basement, a lonely teenager is writing in his blog: "just like in 1947, the truth got out, but now the coverup begins".

      --
      new sig
  3. Scientists or politicians by Kupfernigk · · Score: 5, Insightful

    OK, perhaps slight trolling, but this is an example of why, on everything from evolution to climate change, I prefer the views of scientists to those of politicians or the religious authorities. This is an example of research happening exactly as it is intended to. Initial unexpected result, investigation, experimental flaw, better experiment. It creates a warm glow in the callous, hardened bit of my brain that was once a young, enthusiastic researcher.

    --
    From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
    1. Re:Scientists or politicians by ultranova · · Score: 3, Insightful

      Give you an example: evolution. Religious faith in science says "Evolution is proven. Anyone who believes otherwise is batty." A more scientific viewpoint of it would look at the progression of evolution theory, and see that evolution is simply a pretty good theory that definitely has needed refinement, and almost as definitely will still need refinement.

      You picked a bad example. With everything from breeding dogs to bacteria developing immunity to various drugs to fossil record speaks in favour of evolution, I have a very hard time to believe that any arguments against are done in good faith.

      A person with that second viewpoint will look at creationists' arguments against it -- and they do have some good ones -- not as being batty, but actually as pushing the theory to account for holes that still exist.

      Creationists aren't making scientific attacks against any particular evolutionary theory, they believe that the Genesis is a literal depiction of events and that evolution - specifically, the concept that humans evolved - conflicts with this (ironically, a literal reading of Genesis would actually require evolution to happen afterwards to get from two humans to current multiple ethnicities), so they come up with (usually batshit insane) attacks against it (and science in general, since studying the world will pretty much inevitably lead to the concept of evolution), with the whole Intelligent Design thing being the latest.

      Let me assure you: it isn't that the creationists are wacko. It is that they've really found a flaw in the theory.

      Yes, they are. Specifically, they are starting with an unassailable preconception of reality - namely, that the Genesis is a literal depiction of events that took place 4000-10000 years ago - and fit all evidence into this framework. This, of course, results in an extremely twisted worldview. And the "flaw" in evolution is that it conflicts rather seriously with creationism.

      None of this means that creationism is false, BTW; in other words, none of this proves that the world wasn't created 4000-10000 years ago (or last Thursday, for that matter). It's just that no one would look at all the available evidence and come to that conclusion without having an unassailable (by evidence) belief in it beforehand.

      In other words, "creationism" is what happens when confirmation bias meets bad theology and crusader mentality.

      --

      Forget magic. Any technology distinguishable from divine power is insufficiently advanced.

  4. This probably dates me, but... by Biff+Stu · · Score: 3, Informative

    299,792,458 m /s. It's not just a good idea. It's the law.

  5. Re:Gravity defiant? by elgeeko.com · · Score: 3, Funny

    ehiris did, on March 16th, 3:59pm.