Another possibility that occurred to me (which is probably way off, and has likely already been trivially disproven by some simple experiment that I'm not thinking of at the moment) is that the "speed of light" that we tend to measure is actually a bit lower than the geometrical "c" that appears in equations (I'm not sure what the state-of-the-art is on measuring that geometrical quantity directly), because for some reason photons are slowed as they move through the vacuum (similar to how we can very easily slow photons by making them move through glass, except this would have to be via interactions with the vacuum or some other form of matter). It could be that the vacuum itself has an index of refraction for photons not quite equal to 1 due to some unknown interaction.

Neutrinos interact with almost nothing, so it's conceivable that they even if they have a small amount of mass and travel slower than geometrical "c", they could still end up going faster than photons because they slip through background interactions with ease.

Again, this is wild speculation, "c" is used all over the place, and if we had the wrong value for it, that would require a lot of coincidences, that this sort of vacuum index-of-refraction effect also had the side effect of making other measurements involving the speed of light (energy measurements, for instance - I would tend to think a discrepancy would be way more obvious here, involving, as they do, factors of c^2) come out looking correct, and that seems unlikely to me.

Then again, so much of what we directly measure is grounded in e/m interactions, so there's a chance (vanishingly small, as it is) that a fifth decimal place discrepancy in photon-in-vacuum-c vs. geometrical-c could escape notice because of the relative difficulty of directly measuring geometrical-c, especially if whatever vacuum effects that slow photon travel had other side effects that dunged up our energy measurements, too.

Not that I understand that.

He said it in his recent "Ask me anything" session on reddit.

They know the distance to within +-20cm, so the 76cm of Earth's rotation would be very significant (but not significant enough, again with my rough calculations, to bring these results back in line with c).

The distance is significant enough that to get an accurate measure of c over that distance you would have to take it into account. ie. it would be obvious

I suppose my question is - all things being relative, why aren't the neutrinos bound to the same frame as the emitter and detector?

I also see now that I misread the grand-parent post. Of course these motions would not affect the measurements, and if they did, the rotation of the earth alone would be obvious.

I'm sure that the effects are tiny for the LHC, but are they accounted for at all?

Actually no. The speed of light is constant in ALL frames of reference, whether inertial or not. The math just gets more complicated in non-inertial frames. (That's the difference between special and general relativity.)

UPDATE: it's actually a little more complicated than that. See http://en.wikipedia.org/wiki/Propagation_of_light_in_non-ine...

> I'm sure that the effects are tiny for the LHC

Actually, gravity is a pretty significant factor. See e.g.:

http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps....

The sense I've gotten is that the most likely culprit is some sort of systemic error in the software somewhere, as that stuff is the most labor-intensive part of the experimental setup to analyze for errors.

4) High energy neutrinos spontaneously teleport themselves (casualty saved, new, very odd physics needed)

...

n) Subtle measurement problem (impossible to falsify until the result is replicated on independent setup)

Physics, as I'm sure you know, has undergone many revolutions in its understanding of the world. This could be the start of a new one, or it could fizzle and be a quirky measurement error. In either case, highly worth following to see what happens.

But while it's not unthinkable that relativity requires revision under some circumstances, it's one of the most thoroughly and repeatedly proven tenets of modern physics. It's going to require something much more definitive and reproducible to overturn that mountain. I wouldn't expect a positive answer to this inside ten years, but a negative answer could turn up any time since it depends on someone finds the bug in the gears.

Many problems in science are considered to be "twenty year problems," by which we mean that they'll probably be solved eventually, but that it's unlikely to be any time soon. Many such problems go on for much longer without a solution despite significant progress (see also: fusion power plants). This isn't quite on that scope - but it could evolve into one if it actually ends up with a result which can be reproduced on command.