There has been an article circulating through the popular media which claims physicists at the Large Hadron Collider have observed subatomic particles travelling faster than the speed of light. They claim that this disproves Einstein's theory of relativity, and so are getting a lot of attention. Unfortunately this highlights several flaws in the way scientific results are reported, and perhaps more disturbing proves a lack of physics knowledge by active physicists.

For in spite of the claims made in the articles, there is no proof at all that the theory of relativity is violated.

The supposed discovery is based on measurements at the LHC of neutrinos (very small, electrically neutral particles) that arrived at the detector a full 60 nanoseconds faster than light. The first point to consider is the accuracy of the data - neutrinos are by their nature very difficult to detect, and it is possible that the data is simply wrong. They could have detected different neutrinos than they produced, or they could have detected something else entirely. The dramatic claims of disproving Einstein should wait until the experiment has been reproduced or at least re-analyzed by other teams. At this point it is far too premature.

The second possibility is far more interesting though, because it highlights a misunderstanding of the theory of relativity that is unfortunately prevalent even within the physics community. Einstein's theory does allow for faster than light travel in at least four different ways, so there is nothing new there. What it actually forbids is the transfer of information at faster-than-light speeds.

So it is also possible that in this experiment, a random ensemble of completely identical neutrinos is being produced and travelling at random speeds to the detector. Then no information is transmitted superluminally, and the theory of relativity still applies. (Another way to think about this effect is through quantum mechanical effects, in which the original neutrino disappears and a new neutrino appears closer to the detector, but carrying none of the original information)

As an example, suppose you transmit binary data by sending out a stream of neutrinos - perhaps with electron neutrinos for 0s and muon-neutrinos for 1s. The data 01101 would be sent as a stream of e-m-m-e-m neutrinos. However in this experiment that speeds are randomized, so the stream arrives in random order - for example m-e-e-m-m neutrinos which gives the received data as 10011. Since the received data is random, there is no information transferred. (As an aside, some people argue at this point that you still transfer data in the number of each neutrino species. However the signal isn't complete until all neutrinos arrive, and that will always be slower than the speed of light)

As another aside, some long time readers may remember a similar claim made almost ten years ago about photons travelling through a ruby crystal at faster than the speed of light. The same argument was used to counter that result, and yet many people in the research field still don't understand the difference between random particles travelling FTL and actually violating causality.

Having said all of this, the question remains could this latest result actually violate causality? Not really, since there are many other more technical reasons why this isn't possible in our Universe. So in spite of the hype, the reality is that this experiment has either made an error, or they have simply observed a well-know quantum mechanical effect that allows FTL travel of indentical particles. Either way, it really doesn't warrant front page news.