Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

Possible Duplicate:
What would be the effects on theoretical physics if neutrinos go faster than light?

Update: Loose cable caused faulty results

Apparently, researchers at CERN have found definitive evidence of particles traveling faster than the speed of light. The article writes:

If confirmed, the discovery would undermine Albert Einstein's 1905 theory of special relativity, which says that the speed of light is a "cosmic constant" and that nothing in the universe can travel faster.

Is this just a publicity stunt, or is it possible that this is legit? (I would like to see the paper for these findings, I love how they conveniently leave that out). In other words, if this is found to be true, would Einstein's theory of relativity really be challenged?

There's some debate in the comments which suggest this doesn't do anything to Einstein's theory. E.g.:

The reporting here is incorrect. Einstein’s theory DOES NOT HOLD that nothing can travel faster than light. That is a very common misconception. Einstein’s theory starts with one axiom (a self evident truth) and one postulate (a statement deemed to be true without further argument). The axiom from Einstein’s theory can be stated: the laws of physics should not depend on the frame of reference of the observer. This is a self evident truth. The postulate can be stated: light will be measured to travel at the same speed by all observers regardless of reference frame. This postulate was based on experimental evidence available in 1905 and still available today. When the axiom and postulate are applied to observers traveling at constant speed relative to one another, you get the special theory of relativity, published as part of Einsteins 1905 paper. One of the conclusions is that “the speed of light is constant and absolute in free space”. It falls out of the mathematics. This conclusion is part of the special theory of relativity. It has to date not been dis-proven. If it is, then the postulate must be incorrect. It would mean that light can be measured to travel at a different speed depending on the frame of reference of the observer. I don’t get from the article that this is what has occurred. When the axiom and postulate are applied to gravitational and accelerating frames of reference, you the general theory of relativity, published in 1916. The general relativity mathematics bring forth strange things like black holes, worm holes, time warps, time travel etc. in the so called “fabric of space and time.” The stuff science fiction authors and buff’s are so enamored with. Including me. Most of it has not been practically realized. Only the more mundane stuff like gravity lenses, time dilation, length contraction have been observed. If any experiment can be performed that is in contradiction to the conclusions, then we would merely say, as would Einstein, that the postulate of the constancy of the speed of light, regardless of reference frame, must be incorrect. That’s not such a big deal, really. It would change a lot of physics. It would be very exciting. But it would just mean that the one postulate, one that none of us have ever been able to intuit anyway, is incorrect.

This is not the first time that experiments have been performed that have particles traveling faster than light in a medium other than free space. In this case neutrinos travel through, air, water and apparently rock faster than light does. That does not violate the fundamental postulate that the speed of light is constant regardless of the frame of reference of the observer.

Get it right.

Dr. Karl Hudnut, UCAR – COSMIC.

Who is correct?

share|improve this question

marked as duplicate by dmckee Sep 24 '11 at 16:51

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

    
Please unclose this question--- it is not a duplicate. The other questions keep confusing "tachyons" (which do not violate relativity) with this irresponsible garbage which does. Neutrino physicists have a bit of a conflict of interest. –  Ron Maimon Sep 24 '11 at 19:06

1 Answer 1

Yes, if this experiment is correct, then relativity is wrong.

This measurement shows that the particles actually travel faster than light. Nothing physical travels faster than light through a medium. The faster than light stuff in a medium is for mathematical constructions like the phase velocity. Like the position of a laser pointer, or the sweep-point of an oscilloscope. These can travel faster than light, because they are not physical objects, but points in space defined by a procedure.

The neutrinos travelling faster than light can be used for faster than light signalling, and violate relativity for sure. But the experiment is busted, and the hype is ridiculous. There is no chance that it is correct, it is relying on an official organization's absolute coordinates for the absolute distance measurements.

share|improve this answer
2  
The OPERA collaboration's paper and colloquium were thoroughly responsible, and they have obviously made strenuous efforts to find the error (which I agree must exist) in their procedures. –  dmckee Sep 24 '11 at 16:54
1  
@dmckee: They have not mde strenuous efforts! The error is probably in the absolute GPS position measurement, but they spend all their time on the stuff they know, like synchronizing clocks to nanosecond precision and measuring relative positions to cm precision. This is all irrelevant if the absolute GPS calibration is off. –  Ron Maimon Sep 24 '11 at 18:50
    
@Ron Maimon: Second test confirms findings –  stoicfury Nov 18 '11 at 22:52
    
@stoicfury: The results are certainly rubbish, and the second test is them doubling down on nonsense. It is not a confirmation, it just shows that they made the same stupid mistake twice. It is just plain impossible to account for this based on current theoretical understanding, and they did not give a detailed enough description to find the error, beyond noting that it is the same order of magnitude as the expected errors based on the rotation of the earth. –  Ron Maimon Nov 19 '11 at 4:00
    
@stoicfury: reading the article, this latest check confirms that the error is not in the beam-width. Yeah, yeah, I knew that already, since they spent all their time thinking about beam width. It is certainly a rotation-of-the Earth-improperly-accounted-for error, and the fact that they dismiss these explanations without publishing details means that there is no point in reading this paper or any other from that collaboration. –  Ron Maimon Nov 19 '11 at 4:07

Not the answer you're looking for? Browse other questions tagged or ask your own question.