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Faster-Than-Light Particle Results To Be Re-Tested
surewouldoutlaw writes "After the astonishing news from CERN that the OPERA experiment had detected neutrinos traveling faster than light speed, challenging Einstein's theory of special relativity, there has been some skepticism over the results. Now Fermilab, near Chicago, has announced it will attempt to replicate the experimental results within four to six months."
How could we see it coming, if it's traveling faster than light?
You deduced its pending arrival by virtue of it having arrived.
The barkeep says 'We don't serve faster-than-light particles in here'. A neutrino walks into a bar.
Confirmation of the results of an experiment by an independent party is standard practice in the scientific community. Without it, the findings wouldn't even be considered completely valid! Nothing to see here...
They already did the experiment, and actually found similar results but did not claim any significance. Of course they are going to repeat this, once they finish kicking themselves.
The process is working.
The scientists at CERN asked for peer review and checking of their methodology. This announcement means that at least on paper the method was near-perfect for Fermilab to be committing resources in the near future to prove/disprove it.
I see what you [are going to do] there.
They say a little knowledge is a dangerous thing, but it's not one half so bad as a lot of ignorance. - Terry Pratchett
I did have a college physics covering relativity but it was a long time ago. Correct me if I am wrong, but Einsteins Special Relativity theory doesn't prohibit speeds faster than light. It just prohibits speeds EQUAL to the speed of light. If so, It would be problematic to accelerate past the speed pf light or to decelerate to slower than the speed of light.
Could you elaborate, please?
Having neutrinos fly at 'true c' rather than a lower 'apparent c' isn't a good solution, because it doesn't take in account neutrino bursts from supernova 1987A. The neutrinos from that supernova were detected only four hours before the light from it. That's explainable with what we know about internal stellar processes. But if the neutrinos were flying FTL then they should have arrived four years earlier.
The most likely explanation for the CERN results (apart from experimental error) is that neutrinos are tachyonic -- they have imaginary mass, and naturally fly faster than light. The higher their energy, the closer to lightspeed they travel.
That's not a trivial situation. To use a technical term, it breaks relativity into itty bitty pieces. We will have to change a lot of theories around. But it's unlikely that the value of c is going to change.
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Six if they don't. ;)
I talk about stuff.
OPERA has just found that either neutrinos travel 0.03% faster than photons we've measured, or their equipment has an unknown systematic error. Assuming there's no equipment error, I would find it more palatable to assume that light around Earth travels a bit below c and that neutrinos travel closer to c. What we think of as vacuum could really be a medium with refractive index 1.0003, perhaps due to a uniform background of weakly-interacting particles (maybe even dark matter) that affect photons but not neutrinos.
I have a physics undergrad degree; if there's someone here with better qualifications, would you care to weigh in on the idea that c could be 0.03% faster than the speed of light we measure on Earth?
Expected time to finish is 1 hour and 60 minutes.
There once was a lady named Bright,
Who could travel faster than light.
She left one day
In a relative way
And came back the previous night.
So, either you already saw it coming, or you didn't :-)
Now, to understand it better, read All You Zombies by Robert Heinlein (pdf of complete story). Considered by many to be the greatest time travel short story ever.
The theory of Relativity still holds true, what this experiment (if it's accurate) changes is our idea of matter and causality: if neutrinos have imaginary mass, they are allowed to traver faster than light, as tachyons; and causality may have to be revised, from a onward moving arrow to a regular dimension, in which the future can influence the past.
http://www.gizmodo.com.au/2011/09/nikola-tesla-predicted-faster-than-light-particles-in-1932/
If they succeed in recreating the measurements, doesn't it just mean that c was set at too low a value, and that the true speed to light in a vacuum is slightly faster than originally thought?
c is not a fundamental value, its a function of the permeability and permittivity of either empty space or some dielectric (something like inside a piece of coaxial cable, etc). Or rephrased, you are arguing the impedance of free space is wrong, and generations of antenna and RF engineers would disagree with you. Also c shows up in energy mass equivalance e=mc2 and all that which seems quite accurate. And in time dilation experiments it seems to work quite well. Astrophysics "stuff" thats far away seems to confirm that neutrinos do not exceed light speed in vacuum; this test involved blasting thru rock instead of vacuum so that is no huge problem; theres a long history of shoving light thru materials results in weird behavior. Given how many decimal places that kind of stuff has been verified, more than this result which was only 6 sigma or whatever, I'm thinking fundamental constant fine tuning is awful unlikely.
In summary, either its wrong (which seems unlikely given all the verification they did) or its new physics. Simply tuning up the known constants is just not gonna work.
To fit other, higher precision experiments, its gotta boil down to something like the logical inverse of the light refraction law, where light slows down in certain materials (like, say, glass) resulting in refraction and timing issues (like pulse dispersion in optical fiber). The analogy is maybe neutrinos "speed up" when rammed thru solid rock due to some strange property of rocks, or floating about in a rock-produced gravity well, or something like that.
I can totally see how previous subatomic experiments would miss the neutrino effect; after all its hard to shove gammas or plain ole light quanta thru a couple zillion KM of solid rock... Its too technologically hard to do, until trying out the neutrinos...
A good example of how F-ing around in the lab doing blue sky stuff simply because you can, is the primary source of interesting ideas.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
I like this one better(for FTL): Light year long stick
I can only assume that they've corrected for General Relativity. Everyone seems to be pointing to the obvious potential sources of error: knowing when the neutrinos are created, knowing when they arrive, knowing the distance that they've traveled.
What about variations in the Earth's gravitational field between the two clocks? Or along the path that the neutrinos follow? You can't call the planet a point-source of gravity - the density of matter is quite lumpy.
I haven't seen a back-of-the-envelope calculation for this...maybe it's orders of magnitudes impossible? Would it require a tiny black hole to throw the timing off by 60ns...or would a big uranium deposit be enough? I could probably do the Lorenz transforms for Special Relativity myself, but General is a bit beyond me!
It's not so simple. We've measured the speed of light to great precision. We know what that speed is, and we know photons are massless, so we know with very high confidence what the speed of massless particles is. If neutrinos travel faster than light, then this is very surprising and points to something new and interesting. I'm avoiding referring to 'c' because it would be ambiguous: in traditional relativity, the constant speed of light is equal to the maximum possible speed, which is also in essence the ratio between space-like and time-like variables in the theory (the slope of light-cones and all that). It's a constant that reappears over and over again, and marvelously it's precisely equal to the speed of light. It can't be as simple as just "we were wrong, c is a bit higher than we thought" because it would immediately mean that "c" isn't as universal as we thought: the symmetry of the universe must be somehow different so that photons and neutrinos (and probably other particles) follow slightly different rules.
But if this result is indeed true, and neutrinos travel faster than light, then this is truly amazing and could mean different things. One possibility is that different particles actually have different 'speed limits' (and different causal cones), so there is c_light, c_neutrinos, etc. There are many other possibilities (extra dimensions, breaking of Lorentz invariance, imaginary mass, closed timelike curves, etc.). All of them amount to a substantial rethinking to some aspect of physics. This is definitely exciting, since it could be telling us something very new! And it won't be as simple as just adjusting a constant a bit. (If we tweak the value of "c" in our equations even just a bit, all kinds of well-tested observations, in everything from cosmology to the functioning of transistors, would come out wrong...).
Lastly, it's worth keeping in mind that it's probably a subtle experimental error (very subtle!). This is still useful, because it will teach us something new about experiment design and possibly even teach us something about particle physics. For instance, the timing calculation is based on certain models of the packet of neutrinos that are generated. But, it could be that the packet that arrives at the end is slightly different than the one sent out at the beginning, thus altering the way one should compute the flight time. This could point to some interesting, previously unknown, ways in which neutrinos are generated, or interact with matter, or interact with each other. In any case it will be interesting.
To a neutrino, space and the planet Earth are almost equally transparent. The neutrinos from OPERA and the neutrinos from SN1987A should be travelling at the same c, and they (apparently) aren't.
The one real difference is that the planet has a gravitational field. That could support some theories which suggest that neutrinos are able to take shortcuts through extra dimensions, but only in the presence of a gravity field. That result would still make relativity choke and turn blue, but it might make sense.
Either way, it doesn't look like a tweaking of the value of c is likely.
Genocide Man -- Life is funny. Death is funnier. Mass murder can be hilarious.
I don't know about Tesla, but this is Yet Another Example... Of the standard scientific method.
You never trust a single result, the experiment always has to be repeated especially in the case of unexpected findings. What I'm really waiting for is data from other accelerators, or experiments (given this experiment may be prohibitively difficult to properly replicate) to corroborate the findings.
I'm not even remotely qualified to comment on this, but I seem to remember light being affected by gravity and thus the mass around it, where as neutrinos are virtually unaffected by normal matter. What this says to me is the neutrinos are showing us what the actual speed limit of the universe is compared to what we think it should be as an observer sitting on a giant ball of gravity rich mass. Basically, in space, they go the same speed, which is why the neutrinos and photons from a distant stellar event show up here at the same time, but on earth, the results might be slightly different.
My gut tells me that this will end up shoring up special relativity and perhaps adding a new understanding of our universe without shattering everything as so many are saying.
If they succeed in recreating the measurements, doesn't it just mean that c was set at too low a value, and that the true speed to light in a vacuum is slightly faster than originally thought?
No, probably not. Einstein came up with relativity after a thought experiment concerning what a light wave would look like if you were traveling at its velocity. Electro-magnetisim does not allow for a stationary vacuum solution, so he figured out that the way out was to have time stopped at the speed of light. If the speed of light isn't the speed of light, this problem reoccurs. Now, you could postulate a material (let's call it the... ether), so that light is traveling slow, while neutrino's bound on ahead, but that also would disagree with various experiments.
One way out is to have the neutrinos be tachyons, traveling faster than light, but that does allow for causality violations. (Read the link.) That is based on pretty basic stuff, so it's hard to escape it. That would trouble a lot of people, but it would allow for neutrino oscillations (changes from one type to another). You can't do that at the speed of light, as time is frozen there. (As oscillations have been observed, that is additional strong evidence that the neutrino velocity is not the new "speed of light.")
And, there is also the Supernova 1987a results, which conflict with these results (as the 1987A neutrinos do travel near c). Maybe there are oscillations between tachyonic neutrinos and non-tachyonic ones, which would be mind-blowing all by itself.
I think that a bunch of theorists will spin their wheels until this is better constrained experimentally.
Actually, if the results are correct, we should be getting the reply by yesterday at the latest.
c isn't just the speed of light. It's a constant that appears in all kinds of equations: sometimes as the speed of light, sometimes as the permeability of vacuum (Maxwell equations, etc.), sometimes as the ratio between matter and energy (E=mc^2), sometimes as the fundamental ratio between space-like and time-like quantities (relativity, etc.), and so on. It's quite amazing that this same constant comes out with the same value in all these different ways. (And, again, we can measure this constant in totally different experiments and come up with the same value.) This points to a fundamental symmetry in our universe, a realization which gave rise to relativity, quantum physics, and so on.
In short, you shouldn't think of it as merely being the speed that light (or any other particle) travels. It's a fundamental value that is deeply entrenched in just about every branch of physics you can think of. It so happens that it's also the speed that photons travel at. (That's, no accident, of course.) Changing the value of c even slightly would propagate through all of our physics equations, and would lead to totally different predictions for a host of results. (More specifically, we would start getting the wrong predictions for many things!)
So the explanation for this new result must be something rather more subtle than just adjusting c.
But I have wondered what physics would say would happen if the object were an ideal incompressible solid strong enough to withstand the amount of force required to overcome its inertia.
I'm guessing it would say that there's no such thing as an incompressible solid. Atoms don't touch each other. You can always move atoms a bit closer to each other if you push them hard enough.
(and you'd have to push very hard indeed to move an object as heavy as a stick that's a light-year long...)
No sig today...
Well, Fermilab must have seen it coming, since they did the replication experiments before they knew about the result.
In the words of Miles O'Brien, "I hate temporal mechanics".
Have you read my blog lately?
It does seem as if natural neutrino sources should have made this effect very apparent years before now if CERN is really seeing what they think they are.
I can, however, think of a couple of reasons why this is different though, although I really doubt that this proves FTL Neutrinos are real.
The CERN experiment was originally about detecting type change in Neutrinos, with the detector spotting only one type of conversion, (Electron Neutrinos that had converted to Muon Neutrinos, if I remember right). Neutrinos formed deep inside the sun undergo a type of conversion before they reach the less dense layers of the Sun itself, but then switch to vacuum conversion and travel much farther between type changes. Supernova observations would all be of Neutrinos that have changed types many, many times as they cross millions of light years, so any difference in speeds would be an average, which might be expected to be very close to C. Even locally produced solar Neutrinos are crossing 93 Million miles. The CERN Neutrinos have not cycled many times in transiting only 700 Km or so..
Maybe we 'got lucky', and observed Neutrinos over a close to optimal distance for them to go through just one type change, and picked two types where the effect was to see faster than light motion rather than slower. Maybe a different experiment design and we'd be seeing (much less spectacular) headlines about how some CERN Neutrinos appeared to be moving slower than Light, as though they had rest masses above what previous experiments showed to be possible maximums, and the general public would be paying much less attention.
Who is John Cabal?
Stronger magnets are always going to be advantageous for a particle accelerator, so yeah, room temperature superconductors (ones that have all the necessary properties to make good electromagnets) would be a major breakthrough. However, in terms of making an accelerator like the Tevatron or the LHC smaller, there are some physical economies of scale that make see-it-from-space rings more suitable than lab scale. Circular accelerators lose energy due to synchrotron radiation; these losses are inversely proportional to the ring radius, so all things otherwise equal, bigger is better. Linear accelerators don't have this disadvantage, but they do require a series of electric field "drivers" along their lengths that pose major difficulties for miniaturization. Like the ring accelerators, the trend is to go big- the proposed International Linear Collider would be about 40km long. Smaller accelerators are of course useful for a number of scientific and even medical purposes, and there are a lot of experiments that compete for beam time at the big facilities- it'd be nice to have more available. However, a giant facility has capabilities that can't be matched by 1000 facilities with each 1/1000th the energy.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
You don't need to include all the wonderful interesting new ideas that are unproven and untested. The neutrinos arrived 60 nanoseconds faster than expected, with an error margin of 10 nanoseconds. So, really, they just have to have miscalculated the distance between the generation point and the detector by 60 feet. (Distance done in feet, due to the extremely convenient "light speed is approximately one foot per nanosecond".) They've already admitted that they could have had measurement errors in the same order of magnitude, so it's not that unreasonable.
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There is no reference light beam, genius. The neutrino detector is deep underground, you can't shine a light through to it.
Depends on how bright your light source is.
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