rotflmao.
So you are fine with the concept as long as it stays out of the realm of science, that is the observable and subject to testable hypotheses?
Really, I don’t get how you can accept so much of the weirdness that is physics and then freak out over this possibility.
*Worst *case - perceived causality is a matter of reference frame: to some degree, at least for some particles, what is our future is their past and visa versa. Honestly, how is that so much more of a gamestopper than the spooky action at a distance of quantum entanglement?
Because it’s not quite that simple. The worst case is logical paradox, not just “perceived causality being a matter of reference frame.” Spooky action at a distance is not a paradox; it is just spooky.
I think the absolute worst case would be the most very exciting thing possible. That would mean our fundamental understanding of logic and or causality were wrong. Now that would REALLY shake things up. We might come up with new theories of those that mean all sorts of things we never thought possible (or even thought of) now are.
Then again, it might just mean we are too stupid to ever figure all this out.
Well, of course! If the neutrinos are moving faster than 299,792,458 m/sec, then they’re experiencing time at a rate of <24 hrs/solar day, so they’re showing up ahead of the paperwork.
For budding sci-fi short story writers, they’re going back in time and arriving before they left, and of course before any paper on them could be written.
Don’t you realize what it means that “the seminar reporting the result at CERN isn’t until tomorrow”? That’s when they’ll generate the neutrinos that we’ve already seen!
billfish678,
Right. We have learned to accept that the commonsense world of Newtonian physics is not how it works when looked at from a very different scale. Yet when those possibilities were first put forth they were too weird to consider. Hence the phrase “spooky action at a distance” as Einstein’s way of mocking the concept of quantum entanglement, and the hard time so many still have grokking non-Euclidean geometry. These things do not fit with the way our minds experience reality. Yet we now accept them as better describing a wider swath of reality than Newtonian physics does.
Personally I see the paradox bits as being a bit restricted to the view of time that we currently have and no more mind boggling than the fact that light acts like both a wave and a particle. Logically it can’t be both, yet it is … and isn’t.
If it turns out that physicists of thirty years from now are telling us that time itself is an illusion, that to some degree all of the future has already happened from the POV of a tachyon and our past is its future and its past is our future and both to some degree already are and have been, that causality works the same way for a tachyon viewed in reverse, but still predictably one thing follows another according to an apparent set of rules, then I will find it hard to comprehend and hard to swallow … but no harder than most of modern physics has been for me to swallow nor more incomprehensible than modern physics would have been to physicists before Einstein.
Chronos, I think you’d cope.
I think the problem is Chronos is just about to finish his PHD disertation on “how there is no way in hell neutrinos travel faster than light” and starting feel a bit queasy about the whole thing 
I never said that I reject the possibility that the neutrinos really are traveling at faster than c. But let’s turn the question on its head: Why are you so quick to dismiss the possibility of invisible prankster gremlins?
I’ve seen plenty of evidence that these gremlins exist. They frequently move my car keys from where I left them. One of their favorite tricks is to rip a hole in one of those cheap plastic grocery bags when there’s a bottle of soda in it. I don’t see why they wouldn’t mess with physicists measuring neutrinos.
Ever since this story came out, I’ve been considering the idea that we’ve been mistaken about the Cosmic Speed Limit. We had thought that the Cosmic Speed Limit was the speed of light, and that nothing, not even neutrinos, could go faster than that. Now it seems that the actual Cosmic Speed Limit is not that of light, but of neutrinos. Light (in other words: photons) is pretty fast, but just a wee bit slower than neutrinos. And because the Speed Of Light and the Speed Of Neutrinos are so damn close to each other, no one noticed the error until now.
I think the above was proposed by a few other posters as well, but I used more words than they did. And I avoided using “c”, because it has two different meanings — speed of light, and cosmic speed limit — which used to mean the same thing, but now it seems that they might be different.
Anyway, what is the argument AGAINST what I just wrote? If I understand the thread correctly, the argument against is this: If the speed of photons is even a tiny bit slower than the cosmic speed limit, then the photons can’t have zero mass. And they can’t even have a tiny nonzero mass, because that would have shown up long ago.
So I guess my real question is this: What makes us so sure that photons really do have no mass at all? Is it merely a conclusion derived from the presumption that the speed of light is indeed the cosmic speed limit, in which case it is circular logic and wrong? Or do we have any experimental data proving photons to be massless?
Chronos,
To respond with more seriousness than you mayhaps intend - I reject the supernatural as explanations for how the natural world operates, be that evoking “God did it” or prankster gremlins. I also would have no use for tachyons that do not ever interact with normal matter, that is are unobservable either directly or by effect and whose existence would make for no testable predictions. Weirdness that does not make sense to my brain adapting for a Newtonian scaled world, that I do accept, so long as it leads to testable predictions that are then confirmed.
The possibility of tachyons has been hypothesized as compatible with current theory, including the possibility that they might interact with normal matter. Gremlins, not so much so. This study is, by itself, not enough to establish that tachyons do exist. Observations, especially those giving unusual results, need to be confirmed. Alternative explanations for odd results need to be explored. And tested. But your reaction, even as a matter of hyperbole, that such a reality would be too weird, so weird that you’d rather accept the supernatural as an explanation, is surprising.
It was a flurry in Italy, a tsunami in the rest of the world.
STILL, no SD. 
So, is it observational, which I have failed to detect, after reading their report? Procedural, again, failed to detect from that report.
Previously unknown neutrino oscillation effect?
If something like the Scharnhorst effect is the explanation, I don’t think that would look like massive photons. It’d be nice if someone could confirm this.
There are, for instance, measurements of photons coming from far away astronomical sources, that arrived simultaneously regardless of their energy – if photons had mass, they should travel at different speeds wrt their energy. Of course, any experimental result comes with error bars, so you can never exactly prove zero mass, but current constraints are already quite strict.
I think it’d look just like the vacuum has a tiny refraction index, so the behaviour of light in vacuum would be analogous to its behaviour in glass, say. Using photons alone, the Scharnhorst effect is generally thought to be undetectable, and at least in the approximation used by Scharnhorst, the vacuum refractive index doesn’t depend on photon frequency, so one would expect a uniformly lowered speed of light. But I’m willing to be corrected here.
It occurred to me these folks must have been excited as hell when they discovered this. First, because its pretty amazing. Secondly, it pretty unexpected. And thirdly, I seriously doubt they were looking for it.
It would be like working an archeological dig of some long abandoned Indian village and instead finding a buried UFO.
Were thier results kept a secret till the announcement? were any rumors going around? Seems like a lot of time and many folks were involved here. And given the results that seems a recipe for someone, somewhere, sometime blabbing.
I’d think their first thought would be along the lines of “We need to find the error before we can publish.”, not excitement.
Well, yeah, but once they finished beating their brains out I think some excitement might just creep in.
The question I have, is what part of the original experiment required such precision in measuring time and distance? I can see how they would probably need to window the detection of neutrinos to exclude background noise, but it seems that the level of precision in time/distance is significantly greater than needed. Indeed had it not been so, they would not have seen the difference in expected times in the first place.
To re-ask the last question in post 12:
The speed of light, c[sub]L[/sub], is exactly 299,792,458 m/s, by definition. The invariant speed in relativity, c[sub]i[/sub], could be larger than this. This is the value that would be used in, e.g. calculating time and space dilation: 1/sqrt(1-v^2 / c[sub]i[/sub]^2). Based on Half Man Half Wit’s calculation in post 98, c[sub]i[/sub] >= 299,792,667 m/s is plausible. (To explain the neutrino velocity, about c[sub]i[/sub] = 299,799,952 m/s would be needed.)
There have been experiments that have directly measured time dilation, but those don’t look nearly accurate enough to distinguish between c[sub]i[/sub], and c[sub]L[/sub]. How accurately has c[sub]i[/sub] been measured, with the assumption that 1/sqrt(1-v^2 / c[sub]i[/sub]^2) is the correct factor, but that c[sub]i[/sub] might be greater than c[sub]L[/sub]?
(I don’t mean to limit this to only time dilation effects. Any relativistic effects are fair game, as long as they aren’t based on assuming c[sub]i[/sub] = c[sub]L[/sub].)
I suspect they feel mostly frustration. They are probably as sure as the rest of us that they’ve made some mistake somewhere.