February 23, 2012
Faulty Wire To Blame For OPERA’s Speed Of Light Experiment Results
A claim by scientists working at CERN that neutrinos had traveled faster than light in a September experiment has been proved untrue, after further investigation led them to find a faulty wire connection between a timer and a computer.
The US journal Science reported on Wednesday that the 60-nanosecond discrepancy that led physicists to believe neutrinos were traveling faster than the speed of light was in fact the conclusion of a bad connection in a fiber optic cable connecting a GPS receiver -- used to correct the timing of the neutrinos´ flight -- and a computer.
“After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed,” according to the Science report, citing people familiar with the experiment. “Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis.”
“We have high confidence in our results. We have checked and rechecked for anything that could have distorted our measurements but we found nothing,” said Antonio Ereditato, a spokesman for the researchers.
The September experiment blasted a beam of billions and billions of neutrinos from CERN on the French-Swiss border near Geneva to the Gran Sasso Lab in Italy more than 450 miles away. The scientists recorded the neutrinos arriving at Gran Sasso 60 nanoseconds earlier than the 2.3 milliseconds it takes light to travel the same distance.
The very thought of neutrinos traveling faster than the speed of light threatened to undermine Einstein´s longstanding principles of the Theory of Special Relativity, which states that nothing can travel faster than the speed of light.
Scientists around the world agreed if the results from the September experiment were confirmed, it would force a fundamental rethink of the laws of physics.
In November, a team of physicists from Italy conducted a study using the same beam of neutrinos at Gran Sasso claiming their findings “refute a superluminal (faster than light) interpretation.”
But instead of measuring the time it took the neutrinos to make the journey from CERN to Gran Sasso, the new experiment, known as ICARUS (http://new.www.redorbit.com/news/science/1112426755/fast-than-the-speed-of-light-not-so-fast-scientists-say/), monitored how much energy they had when they arrived.
Tomasso Dorigo, a CERN physicist, wrote on the Scientific Blogging website that the ICARUS paper was “very simple and definitive.” The ICARUS project showed “that the difference between the speed of neutrinos and the speed of light cannot be as large as that seen by OPERA, and is certainly smaller than that by three orders of magnitude, and compatible with zero,” he added.
“Usually we see this effect when particles go faster than light through transparent media like water, when light is considerably slowed down,” said University of Surrey Professor Jim Al-Khalili, who said he would eat his boxer shorts if the original experiment was proved right.
“So these neutrinos should have been spraying out particles like electrons and photons in a similar way if they were going superluminal — and in the process would be losing energy,” he said. “But they seemed to have kept the energy they started from, which rules out faster-than-light travel.”
The original experiment leaders acknowledged that their findings were due to a faulty wire connection.
On the Net:
- European Center for Nuclear Research (CERN)
- Oscillation Project with Emulsion-tRacking Apparatus (OPERA)