It's early yet, I know, but another scientist claims to have found the flaw in the OPERA experiment that suggested neutrinos travel faster than light. His take is somewhat different than the critique by another scientist which my Forbes colleague Alex Knapp covered just a few days ago.
What's odd is why the OPERA scientists didn't think of this.
According to Ronald van Elburg at the University of Groningen in the Netherlands, the OPERA scientists failed to take into consideration a basic aspect of special relativity: the GPS satellites they relied on to synchronize their ground based clocks are themselves subject to relativistic effects.
It's easy to think that the motion of the satellites is irrelevant. After all, the radio waves carrying the time signal must travel at the speed of light, regardless of the satellites' speed.
But there is an additional subtlety. Although the speed of light does not depend on the the frame of reference, the time of flight does. In this case, there are two frames of reference: the experiment on the ground and the clocks in orbit. If these are moving relative to each other, then this needs to be factored in.
"From the perspective of the clock [on the GPS satellite], the detector is moving towards the source and consequently the distance travelled by the particles as observed from the clock is shorter," van Elburg told Technology Review. Which is to say: it is shorter than the distance measured in the reference frame on the ground. He believes the OPERA team failed to take this into account--indeed, that they thought of the clocks as on the ground, not in orbit.
Van Elburg argues once you take the changing distances between the GPS clocks and the neutrino detectors into account, it cancels out the 60 nanoseconds by which the neutrinos seemed to exceed the speed of light.
I'm sure there will be more reviews in the coming weeks, but as the Technology Review post makes clear, the OPERA experiment could turn out to be one of the more unusual confirmations of Einstein's relativity--rather than a major challenge.
