The Speed of Light Broken?

[peter]

The Barman say's "I'm sorry - we don't serve neutrino's in here".

A neutrino walks into a bar.

Has anybody heard any follow up on the story that the guys over in CERN have obtained consistent and statistically significant results demonstrating that neutrinos travelling between CERN and the underground facility at Gran Sasso have been recorded as exeeding the speed of light by some 20 parts per million - in direct contradiction of Einstein's General Theory.
I know one Oxford academic has vowed to "eat his underpants" if there turns out to be any truth in it, but the CERN boys seem pretty convinced and any theory is only as good as it lasts.........

[I'm Murrin]

If they were pretty convinced, they'd have published results, not just released the raw data and said "hey, we can't work out what we got wrong here".

[peter]

If they were pretty convinced, they'd have published results, not just released the raw data and said "hey, we can't work out what we got wrong here".

Good point, but you can see the temptation to do it that way - it could be academic suicide to go up againstthe big E head to head

[Vraith]

If they were pretty convinced, they'd have published results, not just released the raw data and said "hey, we can't work out what we got wrong here".

Good point, but you can see the temptation to do it that way - it could be academic suicide to go up againstthe big E head to head

Heh...that's so.
With something this potentially big, I might be cautious, too. Release the data in case someone forgot to carry the one somewhere, and avoid lots of blushing and stuttering.
Better that than another "I did cold-fusion in my ice-dispenser!!" fiasco.

[wayfriend]

I heard something about this to the effect that Einstein didn't really claim that nothing can go faster than the speed of light - he claimed that nothing can be accellerated until it reaches the speed of light, which is a different limitation.

Apparently the particles that they've discovered bypass Einstein's limit because they have not been accellerated to the speed that they are at, but instead "have always been travelling at that speed".

[I'm Murrin]

If that were the case it'd be a non-story everywhere except in the newspapers. The fact is the Standard Model as it currently stands doesn't account for this 60ns discrepancy.

[Hashi Lebwohl]

I still suspect error in timing of the particle detectors and not a new particle going faster than c.

If, indeed, some of the neutrinos were travelling faster than c then they would be acting like tachyons. Some introductory information on tachyons can be found here, but the important thing to note is that if tachyons--or superluminal neutrinos--exist then, according to the site, "the principle of special relativity must be false, and there exists a unique time order for all observers in the universe independent of their state of motion".

We already know that moving "backward" in time is possible--a positron moving forward in time is mathematically equivalent to an electron moving backward in time--but this still doesn't violate causality because they are moving slower than c. It is the violation of causality that would be the problematic conundrum here.

[I'm Murrin]

Why does moving faster than c have to mean violating causality? It only means so under the constraints of the model that says it's not possible, and demonstration of the possibility would disprove that model.

[Hashi Lebwohl]

Why does moving faster than c have to mean violating causality?

The thinking is that "moving faster than c" equates to "moving backward in time", in which case you see the result of the experiment before the experiment begins. I don't think those are equal statements, but some physicists do.

Causality Problem.
Superluminal, which includes cases of non-violation of causality.

note: I like the PhysicsWorld site, a subset of Wolfram, because it is the best intro source for science/math information available.

[Avatar]

It only means so under the constraints of the model that says it's not possible...

Well said.

--A

[peter]

Sounds like this is a story that has a ways to go yet....but you gotta love the neutrino gag (not mine I'm sad to say) - It's just typical of what my archetypal physisist would say. I think Feynman would have loved it.

[wayfriend]

I find it interesting that scientists can claim that travelling faster than c is impossible, and at the same time quibble over what would be observed if it happened.

... And some physicists are already rejecting the notion that CERN’s neutrinos broke the cosmic speed limit outright. A paper posted late last week, titled “New Constraints on Neutrino Velocities,” argues that any particle traveling faster than light would shed a great deal of their energy along the way.

... In looking at the neutrino beams that landed at Italy’s Gran Sasso laboratory, Cohen and Glashow found that it was about the same as the beam emitted from CERN in Switzerland. That is, the neutrinos were of roughly the same high-energy flavor at their origin and at their destination.

But that’s not possible if these neutrinos surpassed the speed of light, they say. A neutrino achieving superluminal speeds would emit other lower energy particles--most likely an electron-positron pair-- along the way, and in doing so lose a good deal of its own energy. So the neutrino beam arriving at Gran Sasso should have been “significantly depleted” of high-energy neutrinos.

But this was not the case. Which means, they say, that in all likelihood these neutrinos never achieved superluminal speeds. The anomaly is an error in the data or measurement of the speed, or some other brand of misunderstanding or miscalculation. [link]

[Hashi Lebwohl]

We know things like Bell's Experiment that appear to violate the speed of light, so I suspect that some similar mechanism is at work here, presuming that there was no error with the detection equipment. It's all about the entaglement.

I find it interesting that scientists can claim that travelling faster than c is impossible, and at the same time quibble over what would be observed if it happened.

Even though scientists are supposed to investigate things about which they are unclear or uncertain, the three words that most scientists cannot utter are "I don't know".

In short, they don't know what would happen, for real, if particles moved faster than c.

[peter]

Hmmm....or could be the beginning of a paradigm shift (Kuhn; The Structure of Scientific Revolutions)

[Hashi Lebwohl]

The probability of that is not zero; therefore, yes, that could be happening.

[Avatar]

Exciting times. Even if they're wrong, at least people are thinking about the possibility.

--A

[wayfriend]

LONDON, Nov 18 (Reuters) - A new experiment appears to provide further evidence that Einstein may have been wrong when he said nothing could go faster than the speed of light, a theory that underpins modern thinking on how the universe works.

The new evidence, challenging a dogma of science that has held since Albert Einstein laid out his theory of relativity in 1905, appeared to confirm a startling finding that sub-atomic particles called neutrinos could travel fractions of a second faster.

The new experiment at the Gran Sasso laboratory, using a neutrino beam from CERN in Switzerland, 720 km (450 miles) away, was held to check findings in September by a team of scientists which were greeted with some scepticism.

... "The positive outcome of the test makes us more confident in the result, although a final word can only be said by analogous measurements performed elsewhere in the world."

[I'm Murrin]

The writer of that one's getting a little ahead of theirself. The experiment was the same lab, doing the same thing, but in a way that eliminated only one possible source of error.

[Holsety]

So here's my question regarding this whole thing: how do we know that they were actually traveling linearly, and at the speed estimated? How do we know they are the same neutrinos? From what I understand, we just measured some neutrinos at point A and point B and figured out the speed from that.

If they were pretty convinced, they'd have published results, not just released the raw data and said "hey, we can't work out what we got wrong here".

Good point, but you can see the temptation to do it that way - it could be academic suicide to go up againstthe big E head to head

But it shouldn't be academic suicide to question anyone. Scientists should be open to questions being asked. I'm not saying don't critique alternative viewpoints and discard them. I'm just saying don't look down on someone who poses them.

Apparently the particles that they've discovered bypass Einstein's limit because they have not been accellerated to the speed that they are at, but instead "have always been travelling at that speed".

Where's the evidence backing that up? That we haven't seen them travelling at a slower speed? That's a pretty lacking argument.

"the principle of special relativity must be false, and there exists a unique time order for all observers in the universe independent of their state of motion"

Sounds reasonable to me. People frequently comment on how time seems to speed or slow for them at various times based on fun and other factors. It's taken science this long to figure this out? Countless personal testimonials should have been enough, could have been enough for them to learn from...But not to bash science for finding new ways of discovering it.

But that’s not possible if these neutrinos surpassed the speed of light, they say. A neutrino achieving superluminal speeds would emit other lower energy particles--most likely an electron-positron pair-- along the way, and in doing so lose a good deal of its own energy. So the neutrino beam arriving at Gran Sasso should have been “significantly depleted” of high-energy neutrinos.

But this was not the case. Which means, they say, that in all likelihood these neutrinos never achieved superluminal speeds. The anomaly is an error in the data or measurement of the speed, or some other brand of misunderstanding or miscalculation.

So how do they know it didn't teleport? Or renew its particles somehow after arriving at Gran Sasso?

[Zarathustra]

Hmmm....or could be the beginning of a paradigm shift (Kuhn; The Structure of Scientific Revolutions)

Ah, a very good book. A classic in philosophy of science.