Science News - March 24, 2012

Regarding “Hints of a flaw in special relativity” (SN: 10/22/11, p. 18), there could be a simple explanation for neutrinos being measured as traveling faster than the speed of light in a vacuum. While a vacuum is typically defined as a space entirely devoid of matter, in fact a vacuum is a busy medium with virtual particles continually being created and destroyed. Light passing through a vacuum is affected by such activity.

Neutrinos have such low interactions that they can pass through a lead wall several hundred light-years thick without slowing down. The ultimate speed in the universe is, therefore, that of neutrinos, not photons in a vacuum. It isn’t so much that neutrinos are faster than light in a vacuum, rather that light is slower than neutrinos whether or not the neutrinos are in a vacuum.

As for special relativity, it relies on the
constancy of the speed of light, not on any
particular speed of light. Substituting
the burden of outlier data accumulates
enough that someone questions existing
paradigms. So while the editorial “With
scientific puzzles, all the pieces have to fit”
(SN: 1/28/12, p. 2) was mostly excellent, I
object strongly to the final phrase, “if it
doesn’t fit, you must omit.” Rather, “if it
doesn’t fit, you must understand why.”
Even if the outlier data were in error,
understanding the cause will improve
future experiments. And you never know,
maybe it really shouldn’t have fit!
Al Bogart, Framingham, Mass.

I am in complete agreement with the
reader. I should have stressed that “if it
doesn’t fit, you must omit” is just a gen-
eral rule. The rare exceptions are the
source of exciting scientific advances,
requiring the creation of a whole new
puzzle. — Tom Siegfried
the speed of neutrinos would not affect
the measurable results.

Robert Berliner, Los Angeles, Calif.

Such interactions in a vacuum do slow light down, a phenomenon called the Scharnhorst effect. But this effect is much too insignificant to explain how neutrinos could arrive at a detector 60 nanoseconds earlier than light in a race covering only 730 kilometers. That 60 nanoseconds corresponds to a margin of victory in that race of about 18 meters. A photon slowed by the Scharnhorst effect would lag behind a photon without such a slowdown by only about the width of an atom — after racing for the current age of the universe. — Tom Siegfried

While it seems unlikely the faster-than-light neutrinos are really that fast, it is important to find the cause of the experimental error (if there was an error). Scientific revolutions are the result of years of ignoring data that “don’t fit” until finally

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