tank that serves as the target for the experiment, where a neutrino interaction will produce fast-moving charged particles that can then be detected by the surrounding photomultiplier tubes at the ends. Albert Einstein famously posited that the speed of light in a vacuum is both constant and absolutely the fastest possible speed for any object in the universe. In a vacuum light is always faster, but it needs to escape the star first so the neutrinos get enough of a head start to reach us first. We stop timing the neutrino when it arrives in Italy, and calculate that it moves at a speed that's comfortably below the speed of light. It seems to indicate that you could transform a matter particle (a neutrino) into an antimatter particle (an antineutrino) simply by changing your motion relative to the neutrino. WebAs I have been researching I've come up on many articles claiming that Neutrinos can go faster than the speed of light a miniscule amount but still faster. Weve observed this process: where a nucleus changes its atomic number by 2, emits 2 electrons, and energy and momentum are both lost, corresponding to the emission of 2 (anti)neutrinos. So why, then, do we only see neutrinos traveling at velocities consistent with the speed of light? So much so that they even detect slow earth crust migration and millimetres of changes in distance between source and destination when something like an earthquake occurs. Workers help build the neutrino-beam facility used at CERN to shoot particles to Italy in a 2005 picture. Independent measurements were performed. Indeed, they didn't report "we found superluminal neutrinos" but "we measured data that looks like superluminal neutrinos, but after searching for quite some time still cannot find an error in the experiment, so we now decided to publish so that others can check if we have possibly a real effect; we keep searching for an error anyways." Can neutrinos travel faster than the speed of light? What happened to the idea of tachyonic or other superluminal neutrinos? Whether right-handed neutrinos (and left-handed antineutrinos) are real or not is an unanswered question that could unlock many mysteries about the cosmos. I've seen suggestions such as the gravity of the Earth being different along the path of the neutrinos, which warps space/time unevenly. EDIT it seems this effect is settled to be a missing correction due to sattelite-speed terms: http://arxiv.org/abs/1110.2685. Next year, teams working on two other experiments at Gran Sasso experiments - Borexino and Icarus - will begin independent cross-checks of Opera's results. Thanks for making a community wiki reply. Suppose this is real, that the neutrinos arrive very slightly faster than light would through the vacuum. To save chestnut trees, we may have to play God, Why you should add native plants to your garden, What you can do right now to advocate for the planet, Why poison ivy is an unlikely climate change winner, The gory history of Europes mummy-eating fad, This ordinary woman hid Anne Frankand kept her story alive, This Persian marvel was lost for millennia. Remember, from the reference frame of someone on the satellite, we're not moving, but the Earth is. But light travels at a constant speed. They did another run at the end of October, with beam pulses 1-2 ns wide. Concerning a previous possible tachyon observation? The new setup (3 ns pulses, 20 times shorter than the observed effect) has eliminated the last two points. A question of physics should be repeatedly be confirmed before a postulate or an inference can be derived. Neutrinos and antineutrinos can oscillate, or change flavor, from one type into another when they pass through matter. If so, the observation would Why don't we use the 7805 for car phone chargers? That never repeated. The OPERA experiment data showed neutrinos arriving at the detector surprisingly quickly, supposedly traveling faster thanthe speed of light. Physics Faster-than-light neutrino result to get extra checks News. The little-known history of the Florida panther. conventionally. The neutrinos shaved about 60 nanoseconds off that time, according to atomic clocks at either end synchronized by a satellite. The arXiv paper studied them, and seem to exclude it. (In fact, five senior members of the collaboration did not put their names on the paper.) [2], This experiment doesn't use that sort of 'stopwatch' timing mechanism though. What would be the effects on theoretical physics if neutrinos go faster than light? If you go to measure the neutrinos angular momentum, it will behave as though its spinning counterclockwise: the same as if you pointed your left hands thumb forward and watched your fingers curl around it. It looks like they took an insane amount of care with their measurement of distance and time. 2 hours of sleep? ", Oscillation Project with Emulsion-tRacking Apparatus, or OPERA, Do Not Sell or Share My Personal Information. Before the neutrino was known or detected, it appeared that both energy and momentum were not conserved in beta decays. @Lagerbaer I think the trajectory is all underground it starts in a deep tunnel at CERN and ends under a mountain at Gran Sasso :-). Other By analogy, if Einstein relativised the classical picture, how would this result "relativize" Einstein's theory of gravity? For the majority of neutrinos produced in the modern Universe, through stars, supernovae, and other natural nuclear reactions, it would take about a light-year worth of lead to stop approximately half of the neutrinos fired upon it. It shows that the effect was not a statistical artifact as I proposed above. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. A claim that neutrinos traveled faster than the speed of light would be revolutionary if true, but "I would bet against it," physicist says. A high level description of the problem is given here and a more detailed explanation of the investigation is here. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483). Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Nothing can accelerate to any faster speed. If this would however end up to be the explanation, it would be quite boring. I'm quite impressed that they had ~100ns timing resolution between the two laboratories; the "discovery" came about because they were trying to do ten times better than that. Over 3 years, OPERA researchers timed the roughly 16,000 neutrinos that started at CERN and registered a hit in the detector. But for right now, with current technology, the only neutrinos (and antineutrinos) we can detect via their interactions move at speeds indistinguishable from the speed of light. They should have simply waited until after they had those data before announcing their results. Those bunches lasted 10 millionths of a second - 160 times longer than the discrepancy the team initially reported in the neutrinos' travel time. The mumblings that begin a few months after the initial report, that a loose cable caused a timing chain error, have been accepted by the experimenters. The same lab that first reported the shocking results last year, which could have upended modern physics, now reports that neutrinos "respect the cosmic speed limit" The final nail in the coffin may have been dealt to the idea that neutrino particles can travel faster than light. You would still need to explain why a massive particle (the neutrino) moves faster than a massless particle (the photon). Previous experiments of neutrino speed played a role in the reception of the OPERA result by the physics community. Those experiments did not detect statistically significant deviations of neutrino speeds from the speed of light. The paper is on arXiv; a webcast is/was planned here. All of this holds regardless of the details of the model. I really have a hard time imagining a plausible "goof" explanation at this point. The best answers are voted up and rise to the top, Not the answer you're looking for? The timing itself is based on a quite elaborate statistical analysis. This image shows multiple events, and is part of the suite of experiments paving our way to a greater understanding of neutrinos. Is the speed of light in a vacuum already adjusted for virtual particle interactions? And, in recent years, weve even measured a neutrino coming from the center of an active galaxy a blazar from under the ice in Antarctica. Weve measured neutrinos and antineutrinos produced by particle accelerator experiments. The idea that nothing can exceed the speed of light in a vacuum forms a cornerstone in physics - first laid out by James Clerk Maxwell and later incorporated into Albert Einstein's theory of special relativity. Apparently a CERN/Gran Sasso team measured a faster-than-light speed for neutrinos. It's still gossip, so take this with abundance of caution, but here's what he had to say: 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. Today, at the Thats what Patreon supporter Laird Whitehill wants to know, asking: I know neutrinos travel almost at the speed of light. The team which found that neutrinos may travel faster than light has carried out an improved version of their experiment - and confirmed the result. Every print subscription comes with full digital access. But the three types of neutrino all mix together, indicating they must be massive and, furthermore, that neutrinos and antineutrinos may in fact be the same particle as one another: Majorana fermions. And a cable can go bad if somebody hits it the wrong way with their butt while they are working in the electronics room. Five different teams of physicists have now independently verified that elusive subatomic particles called neutrinos do not travel faster than light. The three types of neutrino almost certainly have different masses from one another, where the heaviest a neutrino is allowed to be is about 1/4,000,000th the mass of an electron, the next-lightest particle. Until theres a revolutionary new technology or experimental technique, this will, however unfortunate it is, continue to be the case. Are there any canonical examples of the Prime Directive being broken that aren't shown on screen? But we cant really do that in practice. Invest in quality science journalism by donating today. Relativity is really well-tested, and it's really hard to conceive of a way that neutrinos could travel faster than light without it having other consequences that we would have discovered by now. Whether right-handed neutrinos (and left-handed antineutrinos) are real or not is an unanswered question that could unlock many mysteries about the cosmos. [10 The neutrino might not actually be travelling as far as they think if space/time is contracted at one or more points along the path where gravity varies. Nevertheless, theres a tantalizing chance we have to resolve this paradox, despite the difficulty inherent to it. If I were conspiratorially minded, I would say they are covering up an uncorrected relativistic effect with a bogus story of a hardware error. The faster-than-light neutrino saga evolved very rapidly, with the whole issue completely resolved within nine months. This image shows multiple events, and is part of the suite of experiments paving our way to a greater understanding of neutrinos. There have been plenty of papers (well, preprints) have been put forward offering various explanations of the OPERA results, but none of them has been widely accepted yet as far as I know so it's rather premature to say the results have been explained. Closing in on the speed of light (Image: Volker Steger/ Science Photo Library) The faster-than-light neutrino saga is officially over. E.g., the delay in the 8.3-km optical fiber has been measured both by two-way timing and using a portable clock, and it's been measured repeatedly over time so that one can rule out changes in optical properties due to aging of the plastic. The error in the length of the bunches, however, is just the largest among several potential sources of uncertainty in the measurement, which must all now be addressed in turn; these mostly centre on the precise departure and arrival times of the bunches. Neutrinos in the MINOS experiment cover 735 kilometers, about the same distance as CERNs experiment. Elusive, nearly massive subatomic particles called neutrinos appear to travel just faster than light, a team of physicists in Europe reports. If you catch a neutrino or antineutrino moving in a particular direction, you'll find that its [+] intrinsic angular momentum exhibits either clockwise or counterclockwise spin, corresponding to whether the particle in question is a neutrino or antineutrino. (2) OPERA should try to verify that the anomaly has an energy dependence. the atomic number of the nucleus changed by 2. but 0 neutrinos or antineutrinos are emitted. If you get rid of the speed limit principle, the magnetic field cannot exist anymore. Last year, OPERA measured that neutrinos were making the 454-mile (730-kilometer) underground trip between the two labs more speedily than light, arriving there It has been posted to the Arxiv repository and submitted to the Journal of High Energy Physics, but has not yet been reviewed by the scientific community. Every neutrino and antineutrino weve ever observed moves at speeds so fast theyre indistinguishable from the speed of light. An experiment that creates particles called neutrinos has called into question Einsteins theory of special relativity. and those interactions that do occur are so low in energy that we cannot presently detect them. Why do the neutrinos (with mass) from a supernova arrive before the light (no mass)? I do not agree with the superluminal neutrinos news for very simple reasons. Consequences for causality if superluminal neutrinos were explained by extra dimensions, Distance and time measurement in the famous Superluminal Neutrinos Experiment. The GERDA experiment, a decade ago, placed the strongest constraints on neutrinoless double beta [+] decay at the time. WebThe neutrinos had apparently exceeded the speed of light . Its possible to have an unstable atomic nucleus that doesnt just undergo beta decay, but double beta decay: where two neutrons in the nucleus simultaneously both undergo beta decay. This article explains it in a very accessible way: To understand how relativity altered the neutrino experiment, it helps to pretend that we're hanging out on one of those GPS satellites, watching the Earth go by underneath you. Given the sheer diversity of possible `goof-up' explanations on this page (all answers combined), I can't help feeling that we are trying to find one plausible way in which this can be MADE to look wrong. Given how big this question is, maybe it would be best to delete this answer? As for distance, they use GPS readings to get the east, north, and altitude position along the path travelled to great precision. @jonathan I'll delete my answer if neutrinos travelling faster than c is confirmed, big question or not ;). Create Your Free Account or Sign In to Read the Full Story. This is a fascinating paradox. It was the closest observed supernova to Earth in more than three centuries, and the neutrinos that arrived from it came in a burst lasting about ~10 seconds: equivalent to the time that neutrinos are expected to be produced. @MSalters: I agree. E.g., it holds both for tachyonic neutrinos without a preferred frame and for models in which neutrinos are not tachyonic and there is a preferred frame. IMO this is only possible if they are synchronised as in the above paper (instant observer) and not in the Einstein way that only considers one path between the observer and any other point (Synchronisation around the circumference of a rotating disk gives a non vanishing time difference that depends on the direction used). If the results from OPERA are accurate, this effect would be a full-blown real Lorentz violation, not just an apparent effect like Cerenkov radiation or astronomical superluminal motion. Sign up to keep reading and unlock hundreds of Nat Geo articles for free. Neutrinos are weird, but they arent that weird. The author is only clarifying that the GPS community doesn't need to read his paper, because it has no impact GPS best-practices, since the issue of precise time-of-flight is not relevant for most GPS uses. After all, this isnt the first report of improbably speedy neutrinos. The journey would take a beam of light around 2.4 milliseconds to complete, but after running the Opera experiment for three years and timing the arrival of 15,000 neutrinos, the scientists have calculated that the particles arrived at Gran Sasso 60 billionths of a second earlier, with an error margin of plus or minus 10 billionths of a second. It was an unusual configuration and needed unusual termination hardware and I must have answered the question "but couldn't you just" a hundred times.). Heres where the disconnect between theory and experiment lies. One popular discussion is of "Faster than light propulsion". @Carl: and this is supposed to make one trust their report, independent measurement by the ICARUS collaboration, Times of Flight between a Source and a Detector observed from a GPS satelite, Measurement of the neutrino velocity with the OPERA detector in the CNGS beam, arxiv.org/ftp/arxiv/papers/1109/1109.4897.pdf, Cosmological Principle and Relativity - Part I, Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. I suppose an explanation along these lines would mean interesting new particle physics. Edit: The "problem" is solved: it was mainly a problem in the timing chain, due to a badly screwed optical fibre. General relativistic effects near the surface of the Earth are of order $(9\text{ mm})/(6400\text{ km}) \approx 10^{-9}$. Its one of the biggest open questions about neutrinos, and the capability to detect low-energy neutrinos the ones moving slow compared to the speed of light would answer that question. There are a myriad of ways the neutrino has shown itself to us, and each one provides us with an independent measurement and constraint on its properties. Your support enables us to keep our content free and accessible to the next generation of scientists and engineers. (another interesting file, also related to this subject): http://www.mednat.org/new_scienza/strani_legami_numerici_universo.pdf. Another reason to disbelieve it is that there are strong and fairly model-independent reasons to believe that it cannot be correct. Frdric Grosshans links to a nice discussion by Matt Strassler Actually the impossibility of FTL neutrinos is quite different from the impossibility of tunnelling through a brick wall. The new findings come from four experiments that study streams of neutrinos sent from CERN in Geneva to the INFN Gran Sasso National Laboratory in Italy. Fermilab might have a better shot. MINOS will soon upgrade its equipment with snazzy new atomic clocks, says Rob Plunkett, a Fermilab physicist working on a MINOS experiment. Quantum Tunnels Show How Particles Can Break the Speed of Light. If a systematic error enters there though, the fact of the precision of measurement with GPS, not disputed, would be a demonstration of the difference between accuracy and precision. All experimental measures of |v-c|/c are within this limit. Ask him to bet against the new results, though, and he says hed be willing to bet his house. The team which found that neutrinos may travel faster than light has carried out an improved version of their experiment - and confirmed the result.
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