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"The race is not always to the swift nor the battle to the strong, but that's the way to bet."  - Damon Runyon

Randall Munroe of xkcd sums up my opinion of yesterday's announcement that physicists at the OPERA detector in Italy had discovered that some neutrinos from the CERN accelerator had apparently travelled faster than the speed of light. For those interested, you can read the paper here. I haven't had a chance to review the paper yet, but I plan to. If it's true, it means that relativity's prediction that the speed of light in a vacuum is the "speed limit" for the universe is false. That would mean having to do a substantial rewrite of some portions of physics.

But don't throw away your copy of A Brief History of Time just yet. The fact of the matter is, this isn't the first time that there was an initial announcement that neutrinos were travelling faster-than-light. Another similar announcement was made in 2007 by a different group, but the results turned out after further review to show that neutrinos travelled slightly slower than the speed of light.

Additionally, as Phil Plait notes, we have good reason to believe that neutrinos don't travel faster than the speed of light. It's not just because relativity has been extensively demonstrated through experimentation. It's also based on our observation of supernovas.

The distance from the detector in Italy to the source in Geneva is about 730 km. The travel time at the speed of light is about 2.43 milliseconds, and the neutrinos appear to have outraced that speed by 60 nanoseconds. If true, that means they were traveling just a scosh faster than light, by about 1 part in 40,000. The neutrinos from SN1987A traveled so far that had they been moving that much faster than light, they would’ve arrived here almost four years before the light did. However, we saw the light from the supernova at roughly the same time as the neutrinos (actually the light did get here later, but it takes a little while for the explosion to eat its way out of the star’s core to its surface, and that delay completely accounts for the lag seen).

But I wouldn’t use that argument too strongly; perhaps this experiment creates neutrinos in a different way, or the neutrinos from this new experiment have different energies than ones created in the cores of supernovae (a good bet). Still, it’s enough to make me even more skeptical of this FTL claim.

All of this remains to be seen, of course. It may well be that neutrinos do travel (slightly) faster than light! But I'm going to hold on to my skepticism until the OPERA observations are repeated by another team of scientists. If the results are verified, though, don't think I'll be upset - it would be awesome! But I wouldn't put any money on the claim being true at this point in time.
