Faster-Than-Light Particle Results To Be Re-Tested 412
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."
Standard practice (Score:3, Informative)
Damn straight (Score:5, Informative)
They already did the experiment, and actually found similar results [arxiv.org] but did not claim any significance. Of course they are going to repeat this, once they finish kicking themselves.
Re:Damn straight (Score:5, Informative)
From TFA: “We should have a result in 4-6 months as the data is already taken. We just have to measure some of our delays more carefully,” - Jenny Thomas.
MINOS was already repeating their measurements, but CERN got the jump on them. It's anyone's guess too whether there was a back channel of information from OPERA to MINOS that might have tipped them off and encouraged them to start taking data early. With so many people involved, you almost have to assume that preliminary findings migrate across the Atlantic pretty quickly.
Re:HOLY REPLICABLE RESULTS BATMAN! (Score:5, Informative)
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 [polvoestelar.com.mx] by Robert Heinlein (pdf of complete story). Considered by many to be the greatest time travel short story ever.
Relativity still holds (Score:3, Informative)
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.
Re:Yet another example.. (Score:3, Informative)
Re:Isn't the problem c? (Score:4, Informative)
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.
Re:Good (Score:4, Informative)
I somewhat disagree. Their results met the criteria of scientific discovery and they (well, I certainly hope!) reviewed their process for any error. So even though they literally, by scientific standard, discovered FTL particles, they explicitly state that they don't actually think they did because it disagrees with existing theories. This is *biased* experimental physics.
Yes, relativity has a good track record, and they likely missed something. OTOH, neutrinos are still a pretty new research topic and maybe relativity doesn't cover all the universe has to offer. I do think that these results should be retested, verified, and studied as much as possible. But I'm also seriously disappointed that an ostensibly legitimate discovery has to be presented as 'we screwed up but we don't know why so look at these' in order to avoid raeg from close minded scientists.
Re:... walks into a bar. (Score:3, Informative)
He doesn't (see).
The neutrino enters and asks for a beer. The barman hears the request and, since he can't see anything, assumes it is a neutrino and answers.
And then we finally see the neutrino entering...
Re:Isn't the problem c? (Score:4, Informative)
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.
Re:Good (Score:4, Informative)
And yet General Relativity isn't even as well established a theory as Newtonian mechanics was (which had a century of observational evidence backing it up), or for that matter geocentric theory, which had millennia of observations backing it up (every scientists before and during Galileo's time believe the Earth was stationary, except for a very very tiny handful. It was actually the scientists, not religion, that rejected Galileo's theory when he first presented it.)
Both of them were overturned by more careful observations, in ways and of things we couldn't or hadn't observed before. We already know General Relativity has issues (specifically, with quantum mechanics), and while its predictions fit well with our observations so far, it hasn't actually been proven definitively. It is entirely possible that it is very accurate, but not precisely true. In fact, judging from the history of scientific theory, that is by far the most likely possibility.
New science is nearly always happens when scientists find something they don't expect. These observations may be an error, or they may be the beginning of the discovery of an entirely new theory that explains General Relativity even better, just as Relativity explained Newtonian physics better.
Re:Good (Score:4, Informative)
No. We already know how to generate and detect neutrinos at will. If they travel FTL, then that means we know how to send messages faster than light = backwards in time. This means we can break causality at will. That is a hell of a lot more than a footnote, it would completely upset our entire understanding of the universe.
I think you're missing a step there:
1. IF we can modulate at will sources of neutrinos which travel faster than light
2. AND IF the interpretation of Special Relativity is true that claims that FTL speeds equal motion backwards in time
3. THEN we can transmit information backwards in time.
Further,
4. IF we can transmit information backwards in time,
5. AND IF transmitting information backwards in time allows us to reverse the choice to send that information backwards in time,
6. THEN AND ONLY THEN do we have to worry about causality violation problems.
It's an interesting problem because there's a number of assumptions in this chain of reasoning.
First, I know it's taken as an axiom by physicists that "FTL equals backwards in time because relativity says so", but I'm not sure why we should believe, a priori, that this is in fact the case. We're talking about interpretations of relativity, not the core guts of it - the Lorentz contraction, which is the observable part. Certainly if (1) were true and it turned out that we didn't get (4), then it would seem obvious that (2) is not in fact true. This wouldn't invalidate most of the predictions of Special Relativity, not its usefulness as a rule-of-thumb calculation tool, but it would invalidate the strict interpretation that nothing can ever ever ever go faster than light. It would just turn out that the Lorentz contraction is a dynamical, not a kinematic, effect - something which is generally true about large numbers of ordinary particles, but doesn't have to be the case for a few exceptions.
The general trend in high energy physics has been to see high-level "laws" as emerging from lower levels of reality which obey very different laws, and Einstein's wider relativity program for a Unified Field Theory never managed to describe the quantum world correctly. Why then should we assume that SR is exactly correct, and not just mostly correct? Einstein was smart enough to spot the problem back when he wrote the EPR paper; he believed in a fully real (ie non observer-dependent) world with hidden variables that couldn't send information to, say, update quantum correlations faster than light. Bell's Inequality proves that both of those beliefs can't be correct. We either have to throw away realism, throw away causality, or we have to throw away a hard lightspeed limit. Occam's Razor suggests that it would be a lot simpler to throw away the lightspeed limit than to throw away causality or realism, but ymmv I guess.
Abandoning a strict interpretation of Special Relativity as describing how time and space "really" behave doesn't mean abandoning all the observations built on it. For example, Oleg Jefimenko [wikipedia.org] has constructed equations which model the Lorentz contraction as a dynamical effect resulting from retarded electromagnetic emissions. The equations are a little harder to work with than the relativistic ones, but they appear to allow for a whole realm of FTL phenomena which is not actually violating causality. Some approaches to nuclear forces seem like they get a lot easier if you can postulate FTL signals at the scale of, say, inside an electron.
Carver Mead (the guy who, perhaps more than anyone else really did invent VLSI microchips, and thus is responsible for the computer you're reading this on) also has his own interesting approach to electromagnetism [wikipedia.org] which is much more quantum than classical. Intriguingly like Einstein's own vision of the universe as made of waves, n