Has the speed of light been broken?

The OPERA1 team based at the CERN particle physics laboratory has held up a startling discovery for scrutiny by the scientific community. Neutrinos - electrically neutral particles produced as a by-product in nuclear fission from stars, so small that they were only recently found to have mass - could travel faster than the speed of light. If verified this could have a profound effect on the scientific community’s understanding of physics, reshaping the last one hundred years of thought.

Scientists at CERN blasted a beam of billions of neutrinos from their location, near Geneva, to the Gran Sasso laboratory around 453 miles away. The particles appeared to travel at a velocity twenty parts per million above the speed of light. "We have established synchronization between CERN and Gran Sasso that gives us nanosecond accuracy, and we’ve measured the distance between the two sites to 20 centimetres,” said Dario Autiero, a CNRS researcher. The neutrinos’ time of flight was determined with an accuracy of less than 10 nanoseconds by using sophisticated instruments including advanced GPS systems and atomic clocks.

The team have spent the last six months trying to eradicate error from the process and establish a reason for the surprising result. Autiero stated, “Although our measurements have low systematic uncertainty and high statistical accuracy, and we place great confidence in our results, we’re looking forward to comparing them with those from other experiments."

Einstein’s theory of relativity is one of the fundamental pillars of physics, and it depends on the concept that the universe has a ‘speed limit’ – no physical object can travel faster than the speed of light in a vacuum. It is unlikely that, if these findings are verified, his theory could still be considered valid in the same way. Although some parts would still stand, extensions and modifications would be required to match these results. In the past, the disqualifying of previous thought has been a common feature of scientific progression, but naturally scientist are cautious to test and approve this discovery before such radical changes occur.

Some scientists have suggested that the particle may have ‘taken a shortcut’ through another dimension, although this is not a mainstream theory. For the moment, the scientists at CERN are just keen for independent verification.

“When an experiment finds an apparently unbelievable result and can find no artefact of the measurement to account for it, it’s normal procedure to invite broader scrutiny, and this is exactly what the OPERA collaboration is doing, it’s good scientific practice,” said CERN Research Director Sergio Bertolucci. “If this measurement is confirmed, it might change our view of physics, but we need to be sure that there are no other, more mundane, explanations.

An OPERA spokesperson, Antonio Ereditato of the University of Bern said, “The potential impact on science is too large to draw immediate conclusions or attempt physics interpretations. My first reaction is that the neutrino is still surprising us with its mysteries.”

Click here to access the collaboration’s result on the preprint server arxiv.org.

Published: Tuesday, 27th September 2011 by Ellen Haggan