The boffins who sent sub-atomic particles on a faster-than-light journey into the past have done another successful experiment that confirms the results.
In the original test, 15,000 beams of neutrinos were fired over three years from CERN near Geneva 720km to Gran Sasso in Italy and the particles arrived at their destination 60 nanoseconds faster than they would have it they'd travelled at the speed of light.
In the scientific brouhaha that followed the results going public in September, critics suggested that the beams of neutrinos were rather long, around ten nanoseconds, so margin for error in measuring the time of arrival was quite high.
The researchers determined to present the world with a new physical reality outside of Einstein's theory of general relativity have now sent shorter pulses to improve measurement accuracy.
The new beams were three nanoseconds long and the test left gaps of 524 nanoseconds between them, but they still confirmed the results of the first experiment.
The OPERA (Oscillation Project with Emulsion-tRacking Apparatus) scientists published their results today on arXiv.org.
"A measurement so delicate and carrying a profound implication on physics requires an extraordinary level of scrutiny," Fernando Ferroni, president of Italian Institute for Nuclear Physics (INFN), said in a release on the results.
"The experiment OPERA, thanks to a specially adapted CERN beam, has made an important test of consistency of its result. The positive outcome of the test makes us more confident in the result, although a final word can only be said by analogous measurements performed elsewhere in the world."
Jacques Martino, director of France's National Institute of Nuclear and Particle Physics (CNRS), said another possible error of the experiment, that the clocks at CERN and Gran Sasso were on an ever so slightly different time due to gravitational time dilation, could also be investigated soon.
"One of the eventual systematic errors is now out of the way, but the search is not over. They are more checks of systematics currently under discussion, one of them could be a synchronisation of the time reference at CERN and Gran Sasso independently from the GPS, using possibly a fibre," he said.
Einstein's theory of general relativity allows for time passing at different rates in regions of different gravitational potential. The differences are small, measured in nanoseconds, but could still account for the faster-than-light results. ®