The European Organization for Nuclear Research (CERN) has reconfirmed the revolutionary September results of its historic experiment that detected neutrinos, a type of uncharged particle, moving faster than the speed of light, according to an announcement from the agency on Friday.
“One key test was to repeat the measurement with very short beam pulses from CERN,” the agency noted in a press release on its website. “This allowed the extraction time of the protons, that ultimately lead to the neutrino beam, to be measured more precisely…The new measurements do not change the initial conclusion.”
The initial experiment, carried out using CERN’s OPERA instrument in Gran Sasso, Italy, involved firing longer beams of neutrinos from CERN’s facility near Geneva, Switzerland, which each lasted 10 microseconds (10 millionths of a second) some 454 miles away to the facility in Gran Sasso.
The new experiment altered this model by firing 20 new, shorter pulses, each lasting 3 nanoseconds (3 billionths of a second), separated by intervals of 524 nanoseconds, in an effort to overcome the margin of error in the first experiment.
That experiment, the original one, detected neutrinos traveling at a speed of 2.39994 milliseconds (0.00239994 seconds) 60 nanoseconds (60 billionths of a second, 0.00000006) faster than the speed of light (2.4 milliseconds in this experiment, or 0.0024 seconds). This diagram from the BBC helpfully illustrates the degree to which the particles moved faster than the speed of light, an unimaginably small but significant amount.
Put another way: The original results recorded the particles traveling faster than light, but only very slightly faster, far shorter than actual length of time that the beams themselves lasted. But the new experiment shortened the length of time that the beams lasted so that the time was shorter than the gap between the recorded beam arrival time and the speed of light.
Additionally, the new experiment lengthened the interval between the separate beams, allowing CERN researchers to escape the question that arose in the first experiment as to whether it was the start or the end of the beam that was being recorded hitting the detector in Gran Sasso.
The results of the initial OPERA experiment, announced September 23, sent shockwaves throughout the particle physics community and wider scientific circle, as the result was thought impossible under Albert Einstein’s Theory of Special Relativity, one of the pillars of modern physics.
“The OPERA measurement is at odds with well-established laws of nature, though science frequently progresses by overthrowing the established paradigms,” CERN reported in its initial finding.
A barrage of skepticism and criticism of the experiment from other scientists within and outside of CERN followed.
Arguably the most compelling counter theory was proposed by Ronald A.J. van Elburg, a professor and artificial intelligence researcher at the University of Groningen in the Netherlands, who noted that the timing recorded in the original OPERA experiment might have been affected by the fact that CERN used satellites to synchronize the clocks in Gran Sasso and Geneva in order to measure the time it took the particles to travel between the two laboratories.
Elburg argued persuasively in a scientific paper published online in October that the satellites’ timing was affected by their motion in orbit relative to the neutrino beams and the two particle laboratories down on Earth. From the perspective of the satellites, the neutrinos were moving away from one laboratory and toward the other, but the laboratories were also moving, with the receiving laboratory in Grand Sasso appearing to move toward and into the neutrino stream fired by the laboratory in Geneva, thus accounting for the faster-than-light result.
CERN writes in its press release that “This test confirms the accuracy of OPERA’s timing measurement, ruling out one potential source of systematic error,” however, it leaves the door opent to the fact that GPS relativistic timing could produce an error. As such, CERN may test OPERA again without relying GPS for timing.
“There are more checks of systematics currently under discussion, one of them could be a synchronisation of the time reference at CERN and Gran Sasso independently from the GPS (Global Positioning System), using possibly a fiber” optic cable, said Jacques Martino, head of the National Institute of Nuclear and Particle Physics at the National Centre of Scientific Research (CNRS), the Telegraph reported.
In addition, the results also need to be re-run independently by other particle physics laboratories, and plans are currently underway for this to occur at the only other two institutions in the world capable of performing the experiment: Japan’s T2K laboratory and America’s Fermilab MINOS experiment in Minnesota. Fermilab previously told TPM that its results were expected in early 2012.
Until then, the truth of the faster-than-light neutrinos will remain an open question. But the new OPERA results certainly don’t help Einstein’s case.
