Einstein, relativity, and much of 20th-century physics have come under assault from an esoteric but far-reaching experiment. A collaboration of 174 physicists fired bursts of neutrinos from the headquarters of CERN, the European Organization for Nuclear Research, in Geneva, Switzerland, to a detector in Gran Sasso, Italy. They tracked 16,111 of the ghostlike particles and measured how long they took to complete the trip. After three years of experiments and intense analysis, the team reported in September that the neutrinos were arriving one 17-millionth of a second early.
The minuscule discrepancy revealed by the experiment, dubbed OPERA (Oscillation Project with Emulsion-tRacking Apparatus), has staggering implications. It seems to indicate that the neutrinos were traveling faster than light, violating what has long been regarded as an ironclad cosmic law. If neutrinos really can do that, then Einstein’s theory of relativity, the backbone of modern physics, could break down. Time could flow in reverse. Neutrino-based messages could reach recipients before they were sent. An effect could precede its cause, which would explode our entire way of thinking about the universe.