Make sure that your fiber optic connectors are properly mated, or else this could happen to you: ---------------------------------------------------------- Loose Cable May Unravel Faster-Than-Light Result Science 02 Mar 2012: Vol. 335, Issue 6072, pp. 1027 DOI: 10.1126/science.335.6072.1027 http://science.sciencemag.org/content/335/6072/1027
Anomalous data suggesting that neutrinos can travel faster than light probably resulted from a faulty connection in a GPS timing system, physicists from the OPERA collaboration revealed last week. Scientists who wish not to be identified say a few persistent OPERA researchers spotted the problem during tests the collaboration's leaders at first opposed. OPERA, or Oscillation Project with Emulsion tRacking Apparatus, is a particle detector housed under the Gran Sasso mountain in central Italy. In September 2011, 171 scientists from the international collaboration announced that thousands of measurements made between 2009 and 2011 seemed to show that neutrinos from the CERN laboratory near Geneva, Switzerland, were reaching Gran Sasso some 60 billionths of a second (60 nanoseconds) earlier than light would—a finding at odds with Einstein's special theory of relativity (Science, 30 September 2011, p. 1809). In November, measurements with shorter, easier-to-time pulses confirmed the anomaly, but many physicists remained skeptical (Science, 2 December 2011, p. 1200). That skepticism has grown with the latest announcement. From December 2011 until a couple of weeks ago, a small group of OPERA researchers carefully measured how much time it takes light pulses to travel along an 8-kilometer optical fiber that connects an external GPS receiver to the Gran Sasso laboratory. The “time stamps” encoded by these pulses are also sent to CERN to synchronize timing at the two labs, but the time that the pulses take to travel along the fiber must be added to the time stamp to ensure that the neutrinos' arrival times are recorded accurately. The investigators discovered that the pulses' transit time varied by several tens of nanoseconds depending on how tightly the coaxial fiber cable was plugged into a socket attached to a card inside the experiment's master-clock computer. The card converts the light pulses into electronic signals. Any loose connection was supposed to stop the pulses from being registered, but instead it appears that the card allowed the delayed pulses to get through. So a loose connection during the experiment would have stamped neutrino pulses with arrival times suggesting faster-than-light travel. Although researchers can't be sure the cable was loose during the experiment, the size of the delays involved is highly suggestive. The travel times of pulses along the fiber had been measured in 2008 by collaboration member Dario Autiero of the University of Lyon in France. A source familiar with the experiment says some researchers thought the measurement should have been rechecked before the neutrino velocity results were submitted to a journal in November, but OPERA's scientific management resisted carrying out such a check. https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly#CITEREFCartlidge2012c _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
