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Last November, the physics world was stunned by the announcement from the OPERA collaboration at CERN that neutrinos from CERN (in Geneva) to the Gran Sasso laboratory (under Mont Blanc in the Italian Alps) appear to make the trip at a speed faster than light.   They seemed to make the trip roughly 60 nanoseconds faster than they would have had they traveled at lightspeed.   This would, of course, completely overthrow some of our basic theories of physics.

Physicists were skeptical, of course, as were the OPERA scientists themselves, but the OPERA scientists simply couldn't find their error, so they made the announcement, causing a firestorm in the media.

These neutrinos would have traveled within a part in 100,000 of lightspeed (but faster).  However, it is known that neutrinos from a supernova in 1987 traveled within a part in a billion of the speed of light, and there is no plausible reason for how those two facts can be consistent.  The energies are different, but no reasonable energy dependence could account for it.     So we were all awaiting other experiments to confirm or refute their experiment.

A nice description of why this was not believed by most physicists is in the diary by fizziks at

However, OPERA has just found a problem that completely accounts for the effect, and thus their neutrinos do not travel measurably faster than light.  Details are below the Great Orange Croissant.

The article just announced in Science at  
explains the problem.   In a brief two paragraph announcement, they say

ScienceInsider - breaking news and analysis from the world of science policy
BREAKING NEWS: Error Undoes Faster-Than-Light Neutrino Results
by Edwin Cartlidge on 22 February 2012, 1:45 PM

It appears that the faster-than-light neutrino results, announced last September by the OPERA collaboration in Italy, was due to a mistake after all. A bad connection between a GPS unit and a computer may be to blame.

Physicists had detected neutrinos travelling from the CERN laboratory in Geneva to the Gran Sasso laboratory near L'Aquila that appeared to make the trip in about 60 nanoseconds less than light speed. Many other physicists suspected that the result was due to some kind of error, given that it seems at odds with Einstein's special theory of relativity, which says nothing can travel faster than the speed of light. That theory has been vindicated by many experiments over the decades.

According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos' flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis.

Most of us are relieved that the universe still makes sense, although if it had been confirmed, it would have been very cool

Originally posted to science on Wed Feb 22, 2012 at 01:17 PM PST.

Also republished by SciTech and Astro Kos.

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