CERN Experiment Indicates Faster-Than-Light Neutrinos 1088
intellitech writes "Puzzling results from Cern, home of the LHC, have confounded physicists — because it appears subatomic particles have exceeded the speed of light. Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a few billionths of a second early. The results will soon be online to draw closer scrutiny to a result that, if true, would upend a century of physics. The lab's research director called it 'an apparently unbelievable result.'" Also on the AP wire, as carried by PhysOrg, which similarly emphasizes that the data are preliminary.
Update: 09/22 20:43 GMT by T : Reader Curunir_wolf adds a link to the experiment itself, the Oscillation Project with Emulsion-tRacking Apparatus, or OPERA, which "was developed to study the phenomenon of neutrino transmutation (neutrinos changing from one type to another. The speed of the neutrinos, of course, was an entirely unexpected observation."
Einstein replied "Check your measurements, son" (Score:4, Funny)
EOM
Re:Einstein replied "Check your measurements, son" (Score:5, Informative)
Re:Einstein replied "Check your measurements, son" (Score:5, Insightful)
Regardless of how many times you repeat a measurement with a faulty ruler, the measurements are still wrong.
How precisely did they measure the 732km?
Re:Einstein replied "Check your measurements, son" (Score:4, Insightful)
They must have overlooked this point. Usually only senior/nobel level reasearchers can understand the extremely complicated system of faulty rulers and suspicious measurement results. In my experience, turning the thing OFF and ON again, would have done it.
Re:Einstein replied "Check your measurements, son" (Score:5, Funny)
How precisely did they measure the 732km?
Why, by closely watching oxens plough [wikipedia.org]!
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With commercial prospector-grade GPS hardware one already can get sub-centimeter precision.
If they used things like laser-ranging satellites then sub-millimeter precision is quite easy to achieve (that's how we can view the continental drift in real time).
Re:Einstein replied "Check your measurements, son" (Score:4, Informative)
According to the ABC article, the particles are showing up 60ns too early. If the particles were in fact traveling at light speed, that would simply mean the detector was about 18 meters closer to CERN than they originally thought. Considering differences in altitude, oblateness of the Earth, the detector is underground, and so on, it isn't hard to imagine an 18m position error over approximately 732,000 m distance measured or calculated.
Re:Einstein replied "Check your measurements, son" (Score:5, Insightful)
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Re:Einstein replied "Check your measurements, son" (Score:5, Insightful)
Re:Einstein replied "Check your measurements, son" (Score:5, Insightful)
the knowledge that is the cornerstone of modern physics, knowledge that has been tested time and time again and found true, is upturned by one experiment?
Well, it's not like it never happened before...
If their finding is correct, it doesn't mean that previous experiments were wrong. It just means that things are more complicated than we thought them to be. It's a darker side of the Occam's Razor - you get rid of unnecessary things, sure, but how do you determine whether they are unnecessary? why, based on your experimental input - you need the simplest model that can explain the results that you see, and predict future results when you test it. Problem is, your experiments might not be covering some edge case, and therefore you didn't see the complete picture - and oversimplified your theory.
Re:Einstein replied "Check your measurements, son" (Score:5, Interesting)
"What's the alternative?"
The alternative is not that Einstein was wrong, but that neutrinos have imaginary mass rather than real mass. This is consistent with observations. We can't measure neutrino mass in experiments, only mass squared, and the error bars on those measurements persistently include some small negative numbers. (And some of these measurements virtually exclude any positive mass^2 values. Other measurements purporting to exclude negative mass^2 values may be the result of over-correction and wishful thinking.)
Imaginary-mass particles are consistent with relativity and were first theorized in the 1960s and given the name "tachyons". High-energy tachyons move near the speed of light; low-energy tachyons move at unlimited velocities. This accounts for the fact that the neutrinos from the 1987A supernova were only 18 hours ahead of the light from the explosion, despite the distance -- they were extremely high energy tachyons.
If neutrinos are tachyons, this could account for a couple of odd things about them - the exceptionally low cross section (likelihood of interaction) and their oscillating between different flavors (electron, muon, tau). Exactly how is a job for the theoreticians, but it seems to me that a neutral particle moving effectively backward in time and at unlimited velocities coupled with low energies is not often going to interact, and imaginary mass could be likened to a rotation or oscillation, much like many other things involving imaginary numbers in physics.
Physicist John Cramer talked about the idea back in 1992 in his Analog column: Neutrino Physics: Curiouser and Curiouser (Alternate View Column AV-54) [washington.edu]
Here's a link to another, slightly more technical look at the idea: Neutrinos Must be Tachyons [arxiv.org] by Eue Jin Jeong. Googling "neutrino tachyon" also turns up several previous discussions.
Re:Einstein replied "Check your measurements, son" (Score:5, Informative)
I seriously doubt that they would have an 18 meter bust, even if they were surveying using 1950's surveying equipment. Errors that creep in using simple trigonometry are on the order of 1:100,000. GPS is a whole lot more accurate.
Margin of errors (Score:3)
Considering differences in altitude, oblateness of the Earth, the detector is underground, and so on, it isn't hard to imagine an 18m position error over approximately 732,000 m distance measured or calculated.
Considering that the world's longest tunnel is 57 km long and they drilled it from both ends and the error when both ends met in the middle was about a half meter, one gets an idea of what's the attainable precision.
If they used the same level of precision, scaling up the error would result in a 6 m error at 732 km. However one must take into account that in digging the railroad tunnel they only went to the precision level they needed for that job, one must assume that the scientists used more precise metho
Re:Einstein replied "Check your measurements, son" (Score:4, Insightful)
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It would only mean that our prior measurements of the value of c were slightly off, and we now have a better measurement.
Only is a strong word. There could be many... many explanations up to and including E != mc^2.
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There is no way they are that far off on the measurement of the distance. They'd be ruining their careers with something that obvious for a claim this big. They'd be laughing stocks for life, and the tools to avoid that outcome are cheaply available (even consumer grade gps would allow them to measure the distance more accurately than the error required to explain this outcome).
And C (the speed of photons in vacuum) has been measured very accurately many times. More accurately than this outcome would al
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Exactly.
This seems more likely evidence for a revision of the value of c or perhaps a measurement of plate tectonic drift.
60 billionths of a second is far more precise than we can measure distance on the surface of the earth.
Gran Sasso is half way down the Italian boot. Is this area so immune to earthquakes or surface deformation
that they can know the distance that precisely?
We don't measure distance in seconds. But if we do measure the distance travelled at the speed of light in 60 billionths of a second, then we end up with something like 18 meters.
I am reasonably sure that we can measure distances on the earth more precisely than 18m.
The speed of light has been measured many times, and this experiment is not going to change the value of c (this experiment is not measuring c more accurately in as much as it is coming up with a different value for it). If c was different tha
Re:Einstein replied "Check your measurements, son" (Score:4, Informative)
Which they point out in the article you didn't read.
"But the group understands that what are known as "systematic errors" could easily make an erroneous result look like a breaking of the ultimate speed limit, and that has motivated them to publish their measurements."
Re:Einstein replied "Check your measurements, son" (Score:5, Interesting)
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My understanding is that there's no 732km-long tunnel - they just fire off a beam of neutrinos in the direction of detector 732km away. So all they need is to correctly determine the distance between the emitter and the detector - which a GPS can do just fine.
Re:Einstein replied "Check your measurements, son" (Score:4, Interesting)
But GPS tech relies on Einstein being right, no?
So we have to assume Einstein was right in order to prove him wrong...?
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That's actually impossible. The meter (or possibly the second) is defined by fixing the value of c.
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Just the meter; the second is defined in terms of the rate of atomic energy level transitions.
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Which would be just as troubling, because all the other experiments that clearly measured the speed of light would be wrong.
Pick your poison. All prior measurements wrong or entire theoretical structure wrong?
Re:Einstein replied "Check your measurements, son" (Score:5, Insightful)
No kidding, extraordinary claims require extraordinary evidence, and this is one mother of an extraordinary claim. Unlike most "fast than c" research that the media distorts, it actually sounds like it would be possible to transmit information using this effect, which essentially upends either relativity or causality. But, these aren't just some cranks doing experiments in their basements, and they are appropriately guarding their choice of words to emphasis the preliminary nature of the research which is a good sign. Hopefully the experiment wasn't too expensive and difficult to perform so we can get some people started on replicated (or refuting) the results.
Re:Einstein replied "Check your measurements, son" (Score:5, Funny)
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Hold on, I just need to wipe the dust off of this LHC I keep in my garage and then we can try to replicate their findings.
Be careful with that dust. It may still contain some dangerous microscopic black holes from your last run. :-)
Re:Einstein replied "Check your measurements, son" (Score:5, Interesting)
Fermilab has a similar setup which should be able to test the results. So does an experiment in Japan, T2K, but they aren't running at the moment because of the tsunami. The actual experiment shouldn't be too hard to do if you have the equipment to make a beam of neutrinos, just point them at a detector and fire away and see how long time of flight was, which means they could probably start working on it fairly soon, though it will probably take months or years to get enough data points to be statistically significant.
Re:Einstein replied "Check your measurements, son" (Score:5, Informative)
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Hold on, I just need to wipe the dust off of this LHC I keep in my garage and then we can try to replicate their findings.
The bean counters told me we literally could not afford to buy an LHC for seven dollars, much less seventy million. Bought it anyway. And guess what? LHC dust is PURE POISON.
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Re: (Score:3, Interesting)
If this is a confirmed finding... we may have just proven that Realism is not a constant assumption of our Universe, which would make the Scientific Method itself a tool with limited but useful application. Or rather, it would prove that there are discoveries in our Universe that can b
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Or rather, it would prove that there are discoveries in our Universe that can be made that are impossible to arrive at via the Scientific Method.
How, exactly?
I'm not sure what you mean by the "scientific method", but science is nothing but the discipline of testing ideas by systematic observation and controlled experiment. As a discipline it has unlimited applicability, and insofar as anything can be known, it can be known scientifically.
What you are saying is gibberish.
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Its not a contradiction if causality doesn't hold! We haven't had any evidence until now, but now that we have it, we will present it 40 years ago. :)
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They aren't claiming that the results are correct. They're claiming that they have yet to find the error. And the article I read made it very clear that the scientists expect there to be some type of error or effect involved that explains the result, without having to have neutrinos breaking the speed of light.
They've retested the experiment and tried various ways of finding the error and have as of now unsuccessful in finding it. So, they're kicking it to the broader community to explain. It is certainly p
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Again, this is only if relativity is true, and these findings are as well. It's more likely, IMO, that relativity is wrong than that causality is wrong, at least f
Re:Einstein replied "Check your measurements, son" (Score:4, Insightful)
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In some alternate Universe known as the Theatrical Release, Greedo didn't shoot anybody at all, much less shoot first.
All indications are that this is only a hypothetical and mythical construct, though some crazed hippies still insist it was real.
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Fuck that noise, I'm gonna get me a neutrino-drive spaceship, next stop is the Horsehead Nebula!
Re:Einstein replied "Check your measurements, son" (Score:5, Insightful)
Yeh, I guess they never thought to check those two variables?
Re:Einstein replied "Check your measurements, son" (Score:5, Interesting)
Well, the proof, if you will, is that the faster anything travels, the more massive it becomes, and thus the more energy is required to accelerate it faster. Basically, any object that accelerates to c would become infinitely massive, or to put it another way, it would require an infinite amount of energy. In short, you cannot accelerate things to the speed of light. Photons basically come into existence at the speed of light.
Since neutrinos do have a mass, it means that CERN couldn't have accelerated them to the speed of light, let alone faster. So either we have a mundane measurement error, or some new never-before seen physical effect has been observed. But considering how intimately linked c is to so many physical constants and laws, I'd say whatever has happened cannot have violated this most essential precept, though beyond the "our ruler is screwy", the possible alternatives make one's head swim.
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It's worth pointing out that the mass of neutrinos has never been directly measured. The "mass" to which we refer is the mass required for a mixing matrix between the neutrino flavors. A more exotic definition of "mass" would be required if the current experimental result were to hold, in such a way that neutrinos wouldn't have "mass" in the sense to which we refer today.
That's all speculative, of course, but the important point is, again, that the neutrino mass has never been directly measured. I know.
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Remember that light does have mass, though. A very very very tiny one, but one nonetheless. (note - it can be calculated out to be ~1.8 x 10-42 g), which is generally just calculated out to zero as it makes no difference almost all of the time. But it does have mass. Everything does. Or else it would not exist at all. The problem is that our equipment is woefully crude when tasked with measuring such tiny numbers.
No rules get broken. Einstein just erroneously assumed that a Photon (light) was the sm
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A photon has momentum, but not rest mass. A neutrino has rest mass, and should therefore obey the local speed limit for the safety of the laws of physics.
CERN IS faster than light (Score:5, Funny)
Yay BBC News! (Score:5, Insightful)
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Re:Yay BBC News! (Score:5, Informative)
Click on the advertisements.
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Click on the advertisements.
Living in the UK, I would have to visit the BBC website through a proxy in order to be able to click the advertisements.
Not so fast... (Score:3, Interesting)
http://motls.blogspot.com/2011/09/italian-out-of-tune-superluminal.html [blogspot.com]
"...the neutrinos are claimed to have arrived 60 nanoseconds before the light. Because this is claimed to be a 6-sigma signal, their total error margin of the timing should be 10 nanoseconds (3 meters over c); recall that the distance is 732 km. I leave it to the reader to decide whether this accuracy is plausible given the messy birth and detection of the particles. One nanosecond is the duration of one cycle of your iPhone microprocessor, among other things. Ten nanoseconds is 40% of the lifetime of the charged pion or 80% of the lifetime of the charged kaon. I can kind of imagine that they're doing something really silly, like imagining that each pion or kaon lives at least for the lifetime and then it dies. But some of them decay immediately; this error could erase most of the 60-nanosecond discrepancy."
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Re:Not so fast... (Score:4, Insightful)
"That's a fallacy. Just because he's been crazy in the past doesn't necessarily mean he's being crazing now. Argue about the idea not the person."
It's a logical fallacy, which means it's technically a fallacy in a formal logic system. The fact that he's been crazy in the past doesn't PROVE he's crazy now. However, being crazy in the past is significantly correlated with being crazy now, so the likelihood he is crazy now is increased by his being crazy in the past.
As for the "idea," his basic idea is summed up by the sentence "Of course they're wrong, but I can't tell you exactly why." The quoted paragraph, for example, is ridiculous - you can take a noisy but unbiased measurement and improve the margin of error by averaging over many measurements (which is of course what they did). As for the rest of it, he brings up a lot of things that suggest faster than light particles are theoretically problematic - of course they are. I didn't see any part where he actually addresses the experiment itself, although I did start skimming a bit after reading a page long random story about a pigeon shitting in his pants.
Re:Not so fast... (Score:5, Interesting)
To me a nanosecond seems pretty big. I've spent a chunk of my time over the last couple of years designing consumer circuits sensitive to changes of 10ps in signal arrival time due to changes in the surrounding bulk dielectric.
You haven't lived until you've read a datasheet with the performance spec:
Deterministic jitter: 300 fs.
Probably a PECL part, but still.
And no, they're not using an instantaneous tau to approximate a decay distribution. Anyone who has ever cooked popcorn knows better than that.
Re:Not so fast... (Score:5, Funny)
And no, they're not using an instantaneous tau to approximate a decay distribution. Anyone who has ever cooked popcorn knows better than that.
Completely wrong. I've cooked popcorn and I have no idea what "instantaneous tau to approximate a decay distribution" means.
time travel.... (Score:5, Funny)
distribution (Score:3)
Re:distribution (Score:5, Informative)
Eh, this happens every few years... what tends to be the case is someone gets a hold of one of the charts where velocities were recorded and due to measurement issues there is a probability curve rather then a simple line... normally you use the curve to determine what the actual velocity was, but you always get at least a couple yahoos that look at the curve, notice that one of the tails goes above C and get all excited that something is going faster then light.
Good thing they are are going to put the findings online to be checked then (they have been looking for errors and have been unable to find any so far).
The result - which threatens to upend a century of physics - will be put online for scrutiny by other scientists.
In the meantime, the group says it is being very cautious about its claims.
"We tried to find all possible explanations for this," said report author Antonio Ereditato of the Opera collaboration.
"We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't," he told BBC News.
"When you don't find anything, then you say 'Well, now I'm forced to go out and ask the community to scrutinise this.'"
Source: http://www.bbc.co.uk/news/science-environment-15017484 [bbc.co.uk]
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Well, its probably more like the scientist probably already thinks almost the same thing as the Slashdot guy, but the scientist actually has to do the work to find the problem with the experiment before actually agreeing in an official sense. They're probably in a bar right now taking bets on how fast someone will find their error.
It is important to state that if scientists have strange results that they can't explain, and they have done due diligence to the best of their ability to throw out experimental
What speed? (Score:5, Insightful)
Was it faster than the speed of light in the given medium or faster than the speed of light in vacuum?
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The paper [arxiv.org] itself is now available and it confirms that the relevant speed is the speed of light in vacuum.
PS: If I had mod points, I'd upvote damas reply.
Phase Velocity vs Group Velocity: C is Constant! (Score:4, Informative)
I am intimately familiar with the interaction of light with matter as a result of having been an avid Amateur Telescope Maker [geometricvisions.com] and Amateur Astronomer since the tender age of twelve.
This led to my acceptance to study Astronomy at Caltech in the Fall of 1982, where I was privileged to attend a non-credit class called "Physics X" that was taught by The Immortal Richard Feynman. You could ask him any question you wanted - it didn't have to be about Physics even - but the ensuing discussion had to be purely conceptual. Questions that would require Feynmen to work out equations on the chalkboard were not permitted.
One afternoon I pointed out to him that the phenomenon that light slows down as it passes through a medium just had to be wrong. When one examines any medium at a subatomic scale, it is mostly empty vacuum with some rare particles that have all been either proven or are suspected to be geometric points. (While Protons and Neutrons have a non-zero diameter, they are each composed of three quarks, which themselves are thought to be point particles.)
"Surely," I pointed out to Feynman, "When light passes through all this vacuous space inside a piece of glass, it always travels at precisely C! How could Snell's Law" - which yields the angle of refraction when light passes through the surface of a medium - "possibly be correct!"
I knew damn well that Snell's Law was correct, as Snell himself experimentally demonstrated the law hundreds of years ago. While he did not measure what the Speed of Light had to do with refraction, we have been able to measure light's speed for over a century.
Feynman replied that when light passes through matter, the charged particles in that matter oscillate in sympathy with the oscillations of the light's electomagnetic field. But because they are all in a bound state, and because accellerating charged particles causes them to emit light of their own, thereby carrying away energy and so dampening their sympathetic oscillation, the movements of the charged particles in matter is not quite in phase with the waves in the light passing through the medium.
Feynman concluded, "The light emitted by the charge particles in matter interferes with the light passing through the medium" - that is, wave peaks add to wave peaks, and so with troughs, while peaks and troughs together cancel each other - "so that the resulting combination of light waves only appears to move slower than C."
Thus the Photons are always moving at a constant velocity of C, but all the Photons in the medium interact so that passing a Photon through the medium will result in the exit Photon being delayed from the timing you would expect from when the entrance Photon entered the front surface. They key to understanding all this is that the entrance and exit Photons are NOT THE SAME PHOTON!
Feynman discusses this in a really lucid way, with rigorous mathematics, in Volume II of The Feynman Lectures on Physics. Volume II covers Electricity and Magnetism, Volume I covers Classical Mechanics - Newton's Laws of Motion and such - while the third volume does Quantum Mechanics. The set of three is expensive but are easy to read, even if you don't know much Calculus, and would be a good investment for any Slashdotter.
I was mortally embarrased to realize years later that I had asked Feynman a really basic, purely conceptual question whose completely rigorous answer led to him sharing the 1965 Nobel Prize with Tomanaga of Japan! Their Quantum Electrodynamics describes the interaction of light with electric charge with complete precision.
Feynman's formulation uses a conceptual drawing called a Feynman Diagram as a calculational and explanatory device. I don't know how Tomanaga formulated his Quantum Electrodynamics, but my understanding as that at first no one could understand why the two theories seemed quite different but always yielded the same numerical results. Some time later Freeman Dyson - Esth
What about a supernova? (Score:5, Interesting)
Neutrinos have been observed coming from supernovae from light years away. There would have been a very noticeable time difference between the neutrinos and the light at that distance if this were true. (Any astrophysicists about to verify this?)
I'm skeptical. I think it was likely a wiring problem. It only takes a few centimeters of wire to make a 60ns delay, and these experiments are notorious for using many wires.
Re:What about a supernova? (Score:5, Interesting)
Neutrinos have been observed coming from supernovae from light years away. There would have been a very noticeable time difference between the neutrinos and the light at that distance if this were true. (Any astrophysicists about to verify this?)
SN1987A results were consistent with neutrinos moving at c, although the precise detection time of the optical signal was some hours after the neutrino signal (which was found in subsequent analysis.) John Simpson tried to use an argument about times and average energies to argue for a slightly later than expected arrival time, to support his 17 keV neutrino.
These results are 60 ns in about 2 ms, or a factor of 0.00003. The LMC (home of SN1987A) is 160,000 light years away, so this would have the neutrino signal arriving several years ahead of the optical signal.
Ergo, your skepticism is justified. Good call on the comparison measure.
would we have noticed? (Score:4, Informative)
If we detected a neutrino pulse would we have a good enough estimate of direction to look for the light? Or even the notion that we *should* look for a pulse of light several years later in the same region of sky? If we did record both by happenstance, would anyone have correlated the two events? That is weird enough that I'm thinking they wouldn't.
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These results are 60 ns in about 2 ms, or a factor of 0.00003. The LMC (home of SN1987A) is 160,000 light years away, so this would have the neutrino signal arriving several years ahead of the optical signal.
Page 3 of the paper in the introduction.
At much lower energy, in the
10 MeV range, a stringent limit of |v-c|/c < 2Ã--10-9 was set by the observation of (anti) neutrinos
emitted by the SN1987A supernova [7].
Tim.
Re:What about a supernova? (Score:4, Insightful)
There are people in the battery industry who will knocking on your door shortly to seize your dielectric material in the interest of national welfare. You need a dielectric constant on the order of 1,000,000 to achieve this (in the context of telegrapher's equations, speed of light varies as sqrt(e_r)). By comparison, relative permittivity of barium titanate ranges up to about 10,000.
You might want to check your math. It takes only a few keystrokes to google "2cm/c in ns".
It would be nice someday if Google would give "2cm/c in ps" the same stature. What a world. Even the metric system can't get a fair shake.
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So these neutrinos travel back in time? (Score:3)
Effect isn't that big (Score:4, Insightful)
The numbers in the Reuter's article show the speed of light for neutrinos is 1 part in 40,000 times faster than the speed of light for normal matter.
I don't think this involves causality violations just yet. All our speed of light experiments to date involve measuring particles involving the electromagnetic force (protons, electrons, photons). Even if confirmed, it could be that there's some measurement error in the EM-derived speed of light, which the neutrino is immune to. In which case, it's not useful for time travel. It simply means our measurement of c was off by a smidge.
And given the small size of the result, if FTL neutrino communication is proved true, I expect the only real-world application would be financial companies trying to squeeze a few more nanoseconds off NYC-London communications.
Error in measuring distance perhaps ? (Score:5, Interesting)
Re:Error in measuring distance perhaps ? (Score:5, Informative)
Re:Error in measuring distance perhaps ? (Score:4, Informative)
They say they've ran the experiment 15,000 times. I would imagine this does involve more than one calibration of instruments.
Verification test? (Score:4, Interesting)
Never stopped me before, why now?
Did they or do they have some way of sending a 'normal' light signal, like say a powerful radio wave, across the same distance and measuring the travel time? If they see it's 60ns longer than the neutrinos then I think we're getting somewhere, neh?
Dark Energy - a thought (Score:3)
All particles with positive mass go slower than the speed of light.
Particles with zero mass go at the speed of light.
Therefore these neutrinos, going faster than c, have negative mass.
Negative mass, plugged into gravitational formula will give repulsion rather than attraction.
If the universe is filled with these neutrinos, it would explain the repulsive force we label as dark energy.
Would someone explain what is wrong with this reasoning?
Re:That small? (Score:4, Interesting)
actually they are saying that this is off by about 6 times the error factor
"CERN says a neutrino beam fired from a particle accelerator near Geneva to a lab 454 miles (730 kilometers) away in Italy traveled 60 nanoseconds faster than the speed of light. Scientists calculated the margin of error at just 10 nanoseconds, making the difference statistically significant. "
still i think somebody is getting a speeding ticket (attached to a Nobel Prize maybe).
Re:That small? (Score:5, Interesting)
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How sure are we that the speed of light in vacuum is really the maximum speed of light? One random idea that comes to mind: What we consider vacuum might not be as empty as we think, it might be filled with some kind of dark matter. Light traveling through matter is slower then light in a vacuum. Thus light traveling through our not-quite-vacuum is slower then the actual speed limit of the universe. Neutrinos might not interact with dark matter and thus get a little closer to whatever is the absolute speed
Re:That small? (Score:4, Interesting)
This is actually the most likely and rational solution, believe it or not. I posted this as well (it's taking time to read down this huge thread). A "vacuum" might actually be full of stuff, and as we have shown, light can be slowed and even stopped/frozen, given the right matter and space to interact with. If C is as fast as light can go in normal space, well, subatomic particles that don't necessarily interact with space the same way (and tend to go through it entirely) very well could travel faster. Exactly like how light travels through water at a specific speed. "Space" might be also be slowing it down.
Given the mass difference between a photon and a neutrino (yes, a photon does have a stupidly tiny mass, though it's calculated - and way beyond any of our detectors currently), the actual speed of light in a real environment where nothing is creating drag on it might very well be thousands of times faster.
No rules get broken. Einstein simply assumed (wrongly) than a vacuum was apparently empty when it's not as far as light is concerned. Note - even his theories are intact, as the "in a vacuum" clause still holds true.
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Re:Which speed of light (Score:4, Insightful)
FTL != backwards time travel.
If light takes 1 day to travel a distance and an FTL neutrino takes 23 hours, 59 minutes and 59 seconds to travel the same distance and then reflect both back at the source, the neutrino arrives 1 day, 23 hours, 59 minutes and 58 seconds after it is sent. That is distinctly not the past.
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Thank you.
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But the speed of light does vary in different materials as a function of the index of refraction.
Re:Which speed of light (Score:5, Informative)
The speed of light in a vacuum (c) is a constant. The speed of light in a non-vacuum is not.
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Article says that it's compared to light taking the same trip. That would imply it's the speed of light in whatever medium they're using.
Light tends not to travel through 'the ground' very well.
Re:Tachyons? (Score:4, Informative)
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Tachyons. Hand in your nerd card.
Re:First Post (Score:5, Insightful)
Consensus != universal fact. Consensus == our best understanding of universal fact. There's a difference. Real science is always open to upending.
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Or they sent a DeLorean and a flying DeLorean arrived.
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And why would this result be impossible?
It's not impossible. But if it was true it would be a bigger surprise than if the Sun decided to rise in the West tomorrow or I found Natalie Portman naked in my bed when I got home tonight.
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Yep it's a myth propagated by anti-science nuts. First popularized by religionists who were angry over evolutionary theory to try to discredit the science.
Re:Why is this impossible? (Score:5, Insightful)
And why would this result be impossible?
It's impossible according to current theories. It's not impossible that current theories are wrong, but very highly improbable to be wrong in this way, given the amount of corroboration we have for the speed of light being an absolute limit and for the time-dilation effects, which would cause faster-than-light particles to violate causality.
Nevertheless, the data is the data, and that's why they're publishing it. Somebody else will find a measurement error (most likely) or we'll get exciting new physics (much less likely, but would be pretty awesome).
Many have posted that the instruments were flawed or the scientists made a mistake, but not too long ago scientists were 100% certain that the world was flat too.
Actually, I'd say that was very long ago. Considering Eratosthenes [wikipedia.org] not only knew that the Earth was round, but was able to calculate the circumference to remarkable accuracy way back in ~200 BC. Note that it wasn't him that decided the Earth was round, that was already common knowledge. He figured out the circumference.
Just because scientists currently believe that nothing can go faster than the speed of light doesn't make it so. Our views of the universe are always changing and saying that a result is "impossible", no matter how unlikely the result, is a bit short sided.
That's true, however as many others have pointed out, extraordinary claims require extraordinary evidence. A single experiment just isn't enough. If we have sufficient confirmation of faster than light effects, scientists will most certainly welcome the result. Unexpected data opens up new opportunities for lots of papers. Scientists live for that, literally. It's what puts food on the table :)
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One obvious error sources would be scale factor errors between (say) GPS measurements of position and the direct measurement of time of flight.* Unfortunately, these come in about about 10^-9, which is 4 orders of magnitude too small for this.
*Basically, GPS, or VLBI, or any modern measurement scheme, tells you where the end points are in some coordinate system. Coordinate systems are tricky things in general relativity, and the common relativistic coordinate system in harmonic gauge will NOT give you the
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They're not telling the people at CERN they're wrong. If anything, it's the CERN physicists announcing that they're wrong, but they don't know why and are looking for help.
Nobody here is going to be able to give it to them. Whatever's wrong is buried deep in the setup. They've already checked all the things they can think of, and they're looking for help. We get to play along with the home game, but we're not going to be the ones who figure it out. We're not contributing, just exercising our brains.
The
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You certainly CAN use GPS to synchronize clocks at the level of a few ns. While the GPS timing signals themselves are not accurate enough to form a stable timebase at this level, there are multiple methods which use GPS to implement time transfer between ground stations at much better than the 10ns level, when use in conjunction with an external high precision oscillator. See, for instance, http://tf.nist.gov/time/commonviewgps.htm [nist.gov] or http://www.nist.gov/pml/div688/grp40/tmas.cfm [nist.gov] and the references therei