In September last year, 15,000 neutrino beams were fired from CERN in Switzerland to the Gran Sasso laboratory, an underground Italian laboratory near Rome, 720km away. Physicists on the OPERA experiment said that despite checking and rechecking results, they believed that the neutrinos had travelled at a velocity of 20 parts per million faster than the speed of light – a theory that challenged the law of physics and put into question Einstein's theory of relativity. The findings were met with much scepticism by the scientific community, but a second test in November 2011 appeared to provide further evidence that neutrinos can indeed travel faster than the speed of light.
"Although this result isn't as exciting as some would have liked," said CERN research director Sergio Bertolucci, "it is what we all expected deep down. The story captured the public imagination, and has given people the opportunity to see the scientific method in action – an unexpected result was put up for scrutiny, thoroughly investigated and resolved in part thanks to collaboration between normally competing experiments. That's how science moves forward."