CERN's experiment accelerated neutrinos to the speed of light and fired them from Geneva to a detector at Italy's Gran Sasso National Laboratory, located 450 miles (724 kilometers) away. According to the project Web site, the goal of OPERA -- Oscillation Project with Emulsion-tRacking Apparatus -- was to detect the appearance of tau neutrinos from the oscillation of muon neutrinos. When the accelerated particles seemingly traveled faster than the speed of light, the OPERA project received a great deal of attention in the media and scientific community.
Most scientists were appropriately skeptical. After all, if these neutrinos were actually traveling faster than the speed of light, a principle theory of physics would no longer be reliable. According to a CERN press release from September 2011, the OPERA scientists spent several months cross-checking their experiments and found no instrumental anomalies that could explain the results.
Using GPS systems and atomic clocks, the OPERA project could determine the speed of its neutrinos down to an accuracy of 10 nanoseconds or less. The science community naturally decided to perform their own tests. The February 2012 meeting of the AAAS, or the American Association for the Advancement of Science, indicated that five similar experiments were gearing up to test out OPERA's claims, but they weren't completely necessary: On Feb. 23, 2012, CERN announced that two elements of their system could've caused the faster-than-light readings.