In September, an announcement from the CERN physics laboratory in Geneva caused headlines with the tentative report that neutrinos send from the lab to detector in Italy 770 kilometers away were measured to travel at a speed very slightly higher than the speed of light. This violated the speed limit set by Einstein in his special theory of relativity, published in 1905, that no particle can be accelerated past the speed of light in a vacuum.
Most media reports proclaimed that Einstein had been proven wrong. However, as I reported in a two-part blog titled "No Cause to Dispute Einstein," Part 1, Part 2, the theory of special relativity does not prevent particles from traveling faster than light, as long as they never travel slower. Such particles, never before seen, are called tachyons.
However, Einstein noted that the existence of tachyons wreaks havoc with the notion that cause must always precede effect. I gave an example where an observer on a tachyon watching the 1804 dual between Alexander Hamilton and Aaron Burr would first see the bullet go from Burr's gun to Hamilton's abdomen, and then see the bullet fly back from Hamilton's abdomen to Burr's gun.
However, I did report that I, along with most physicists including the experimenter's themselves, felt that some experimental mistake would eventually be found to account for the measurement and Einstein's speed limit would remain in force.
Well, that seems to have occurred. On February 23 CERN issued the following press release:
The OPERA collaboration has informed its funding agencies and host laboratories that it has identified two possible effects that could have an influence on its neutrino timing measurement. These both require further tests with a short pulsed beam. If confirmed, one would increase the size of the measured effect, the other would diminish it. The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino's time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken. If this is the case, it could have led to an underestimate of the time-of flight-of the neutrinos. The potential extent of these two effects is being studied by the OPERA collaboration. New measurements with short pulsed beams are scheduled for May.
A loose connection is certainly an embarrassing mistake. But it is not anywhere near as embarrassing it would have been if someone else besides the investigators themselves had discovered it. The story is one of good science in action, where any extraordinary claim must be checked and checked, over and over again.
Perhaps the best lesson learned from the affair is that scientists making what they think is a major discovery should hesitate before going public. In fact, I remember when it was the policy of major science journals not to allow public notices until the date of publication of a paper. That would be well after the peer-review and editorial processes were satisfactorily completed.
Unfortunately, that seems no longer possible with today's instant media. Some blogger somewhere is likely to pick up signals of something important happening. So, I guess that best we can do is take everything we read with a grain of salt. My rule is, don't believe any report until it has been independently replicated and all replications have a calculated significance that precludes the reported effect from being a statistical artifact.