@37 Skepttic: I think that only works with tachyonic neutrinos (if they exist)
But cheezy jokes, eh? Ok, now we’re on MY turf

A billion neutrinos walk into a bar. One says “Oof!”
______________
A neutrino walks into an (actual drink-serving) bar. The bartender says “Hey, we don’t serve your kind around here!” The neutrino replies “Just passing through.”
______________
A cop pulls over a subatomic particle. He walks up and says “Do you know how fast you were going?” The particle replies “No, but I know where I am.”
(Ok, that one’s pretty close to the Heisenburg one)
______________
An atomic nucleus is talking to her friends when she stops and says “Jeez I feel bloated. I think I put on another two electrons.” Her friend replies “Stop being so negative!”

The barman said: “Sorry, we don’t serve neutrinos here.” A neutrino enters a bar.

from this article (he found it on twitter, not sure who came up with it)
http://www.guardian.co.uk/science/2011/sep/24/einstein-e-equals-mc2

It’s a pretty good one, along the lines of Heisenberg was driving down the highway and a cop pulls him over …

Always good to crack one of these physics jokes, laugh hysterically and see if anyone else gets it.

Which other good ones are there?

I might be dead wrong here, but have there ever been any experiments that actually showed some physical principle that’s bound up in causality?

Not that I’m aware of, but if causality breaks down, it’s very difficult to come up with an explanation of the universe that makes any damn sense. It all becomes paradoxical and nonsensical. I’m not talking about “twin paradox”-type paradoxes, which seem like paradoxes but really aren’t; and I’m not talking about spooky quantum entanglement-type nonsensical, which is extraordinarily counterintuitive but still all works out mathematically. If you don’t have causality, then you wind up with “This statement is false”-type nonsense, except it’s making a mockery of reality itself instead of just symbols.

You can always argue that there is some way to make sense of it all that we just haven’t thought of yet. But it seems awfully hard to come up with that.

Add to that the fact that every time it seems like there is some loophole that allows us to get around causality, e.g. FTL travel, creating a wormhole, etc., it turns out not to pan out. (I realize my dismissal of wormholes may be controversial, but my understanding — correct me if I’m wrong — is that to make it work requires exotic matter, and IANAPhysicist, but I see no reason to believe exotic matter exists under any circumstances). It’s a conjecture, for sure, to say that causality must hold, but it seems a likely one. IMHO.

One thing that I’ve wondered about this oscillation is over what distance it occurs,ie, if the oscillation is instantaneous, there is no distance covered during that process but such “instantaneous” processes appear to be limited by the Plank time(10^-43 sec) and in that 10^-43 sec, where does the energy of the muon neutrino go? ,,,back into the false vacuum?,,,or into another dimension? ,,,and QM might dictate the “re-emergence” of that particle energy as a tau neutrino from the false vacuum some distance further on than its starting coordinates,,,said distance being sufficient to explain the super luminal observation we apparently have here, which also goes some way to explaining why the neutrinos from the SN1987a didn’t arrive on earth years ahead of the visible EM,,,they were traveling thru vacuum, so had no matter-mass effect(and no oscillation).

Gary 7

/disclaimer: I fully and freely admit that I barely know what we’re talking about, so I hope I’m not wasting anyone’s time.

If special relativity applied to all massive (mass-having) particles (this has been the operating assumption up until now),

then plugging a greater-than-C velocity into the Lorentz transformation yields a negative time displacement (ostensibly meaning backwards travel in time).

However, perhaps special relativity, more specifically Lorentz invariance does not apply to neutrinos (despite the fact that they have mass). This would mean that neutrinos could travel faster than light without “going back in time”, i.e. there would not be any new implications for causality.

My question would then become “Why does Lorentz Invariance appear to apply to some masses but not others?”.

(((btw this situation is different from tachyons traveling faster than light, since tachyons have imaginary-valued mass whereas neutrinos have real-valued mass.)))

I’m glad you brought up the C-word
The nature of causality has always fascinated me – it seems so ironclad, and yet, unlike, say, FTL acceleration, it’s difficult to point to a certain process that “enforces” it (per the FTL example, we know that accelerating an object to the speed of light takes an infinite amount of energy because the effective mass of the object you’re accelerating also becomes infinite).
I might be dead wrong here, but have there ever been any experiments that actually showed some physical principle that’s bound up in causality?

Man, this excites the heck out of me,,,

Gary 7