Slashdot Mirror
CERN Experiment Indicates Faster-Than-Light Neutrinos
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."
EOM
SJW: Someone who has run out of real oppression, and has to fake it.
I hope those results are correct. It would be very amusing.
I searched for 'faster than light' on the CERN website, got articles posted in 2012, 2014. They put this new discovery to work right away!
Pavlov wouldn't be so famous if he'd used a can opener instead of a bell.
This was a rational piece without too many sensationalist remarks! How do we show them we appreciate decent scientific writing as opposed to the crap we normally get?
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).
Any person using FTFY or editing my postings agrees to a US$50.00 charge
But the speed of light does vary in different materials as a function of the index of refraction.
Visit the
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.
And if it's actually an accurate result then it doesn't matter how small the value is. As soon as you break the speed of light by _any_ amount then the theoretical doors are wide open. According to Einstein breaking the speed of light by even just one nanosecond is _exactly_ as impossible as Star Trek variety warp speed.
This Space Intentionally Left Blank
Tachyons, if real, cannot decelerate. They also have imaginary mass according to special relativity. Of course, perhaps relativity isn't as complete a theory as we once thought.
FanFictionRecs.net
http://motls.blogspot.com/2011/09/italian-out-of-tune-superluminal.html
"...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."
There was a young lady named bright : who could travel much faster than light : She went out one day : in a relative way: and came back the previous night.
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.
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.
Was it faster than the speed of light in the given medium or faster than the speed of light in vacuum?
The speed of light in a vacuum (c) is a constant. The speed of light in a non-vacuum is not.
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.
Take a look at this useful primer about faster than light travel and what it would mean for modern physics. It sure would be interesting. No, amazing!
Tachyons. Hand in your nerd card.
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.
And if it's actually an accurate result then it doesn't matter how small the value is. As soon as you break the speed of light by _any_ amount then the theoretical doors are wide open. According to Einstein breaking the speed of light by even just one nanosecond is _exactly_ as impossible as Star Trek variety warp speed.
Indeed, according to Einstein, in the right reference frame it is Star Trek variety warp speed. Indeed, there's a frame of reference where the speed is infinite. And a frame of reference where the neutrinos were detected before they were generated.
In other words, there are only three possibilities:
* The measurement is wrong
* Relativity is wrong
* We can send messages to the past using neutrinos
At least one of those must be true.
The Tao of math: The numbers you can count are not the real numbers.
The detector is 732km away for the emitter and light travels at 299 792 458 m/s. In one billionth of a second, light only travels 29.9 cm. If they are off in the precision of measuring a 732km distance by even as little as 30 cm (~1ft), then their timings will be off by 1 billionth of a second.
If that were the case we would end up seeing massive relativist effects in the show, which do not happen. According to Einstein however quickly the Enterprise seems to be traveling or how much space has been warped from its perspective, from Starbase's perspective it's going to take years for Kirk to travel between one star and another.
This Space Intentionally Left Blank
Consensus != universal fact. Consensus == our best understanding of universal fact. There's a difference. Real science is always open to upending.
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.
That is a children's story and is not worthy of posting on slashdot. The first measurement of the diameter of the earth was made in the 3rd century BC. Thinking people of every time time after it were aware of the result, repeated the result and understood the meaning.
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 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 :)
The physics of the past century do not empower us to send humans to other habitable planets. So...they need a good upending.
Thank you.
I am John Hurt.
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.
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 right "proper time" (what the neutrinos should be measuring) if you just find the coordinate distance between two points and divide by c. These effects are of the order of GM/Rc^2 and v^2 / 2 c^2, both of which are no more than 10^-9 for observers resting on the surface of the Earth.
Which direction are neutrinos traveling in reference to the earth's rotation? Could something like that affect the results? I imagine it's the same (on a very tiny scale) as to run down in electric stairs that are going down. Let's see: http://g.co/maps/m8wky. I'm curious can anyone elaborate?
Also, thats awfully close to the earthquake struck city of L'Aquila, I hope no Italian get this news because if theres a quake there in the following days the CERN scientist risk getting charged with manslaughter :/ for "debunking theories of death scientist that unfolds the wrath of Hades causing earthquakes"
Behind, you mean.
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 methods.
So, it's very hard, practically impossible, to imagine that there would exist an error of 18 m in the position of the detector.
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 limited is. The problem would thus not be that C is wrong, but just that it's a little bigger then assumed.
Of course that's just a crackpot idea, I have no idea what I am talking about.
FFS, nothing personal, but could you people stop trying to explain complex physical phenomena with your "gut feeling"?
Here http://en.wikipedia.org/wiki/Time_travel#Via_faster-than-light_.28FTL.29_travel , read it, comprehend it, think twice next time before post something. Tl;dr FTL = time travel in context of SRT.
Mods: You are welcome to mod me down for my bm, but I really had enough with this whole discussion...
This is ridiculously stupid and simple to ask, but I'll fire away anyway...
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?
I do not respond to cowards. Especially anonymous ones.
Another incredible, mind-boggling possibility: measurement error -- the particle did not exceed the speed of light.
Currently hooked on AMP
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.
There's a tiny, tiny, tiny chance that it's not their setup, but that they've actually discovered something. As Asimov said, the real wins don't sound like "Eureka". They sound like "That's funny..." Thus far, "that's funny..." is what we're getting. Most likely, "that's funny" means you've done something wrong. But once in a very rare while, it means something else. And we get to play with it early.
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.
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 or http://www.nist.gov/pml/div688/grp40/tmas.cfm and the references therein.
Or they sent a DeLorean and a flying DeLorean arrived.
How can I believe you when you tell me what I don't want to hear?
Doesn't anyone know what this means?! We've found the cure for all of life's problems! Just send a Tachyon beam at it and bounce it off the deflector dish! Thank you Star Trek for solving all of life's problems for us! Now bring out the green women!.
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.
refactor the law, its bloated, confusing and unmaintainable.
The neutrinos were moving faster than the measured speed of light in vacuum. This is very interesting. We assume that the speed of light in vacuum equals the maximum speed for the transmission of information. That is not _necessarily_ true since vacuum contains quantum fluctuations, dark energy and other quantum effects. In this case "c" would only be an approximation for the maximum speed for the transmission of information. Proposed Explanation: the speed of light in vacuum (c) and the observed neutrino speed are both less than the maximum speed for the transmission of information ( c++ ?).
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?
In looking for possible explanations, isn't it possible that this could be a nice twist towards String Theory? If we assume extra dimensions curled up inside the 3 spatial dimensions of our own + time, isn't it then possible for a neutrino to pass trough a curled up dimension and 'tunnel' it's way to the end point e.g. kind of wormhole?
Also, what was the mass of the neutrino when it went past light speed? Should have been infinitely big.
I am intimately familiar with the interaction of light with matter as a result of having been an avid Amateur Telescope Maker 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
Request your free CD of my piano music.
(AC's comment above was made before the paper was released)
The l'Aquila earthquake shows up very clearly in the results, it was roughly a 5cm shift in the distance between the labs, and the graph shows it so obviously that it's clear they've got at least 1cm resolution. I think any tectonic activity has probably been accounted for here.
Please consider this account deleted, I just can't be bothered with the spam anymore.