Small Particles Raise Big Questions About Foundations of Physics


“May the book bring some one a few happy hours of suggestive thought!!” Albert Einstein wrote that in 1916 at the end of the preface to his groundbreaking book, “Relativity: The Special and General Theory.” Scientists around the globe have since spent countless hours — some perhaps not so happy — thinking about Einstein’s work and the ideas he presented, including the equation E=mc^2, have since served as the bedrock for modern physics.

But the news Friday that a group of European physicists may have discovered that subatomic particles traveled faster than the speed of light (the constant c in Einstein’s equation) could call our fundamental understanding of the universe into question.

“The expected reaction is a healthy skepticism that a result this revolutionary can be happening,” said Rob Plunkett, a physicist at the Fermi National Accelerator Laboratory in Batavia, Ill.

Listen to a conversation with Rob Plunkett:

Researchers at the European Center for Nuclear Research, or CERN, published a paper stating an experiment they conducted demonstrated neutrinos traveled faster than the speed of light.

“Neutrinos are among the weirdest denizens of the weird quantum subatomic world,” wrote Dennis Overbee in The New York Times. They are tiny particles believed to travel at the speed of light and are “electrically neutral,” meaning they can be pass through matter “like wind through a screen door” or “like a bullet passing through a bank of fog.” They come in three varieties, but can change among the three as they travel, something the CERN experiment was intended to detect.

The project, know as Opera, for Oscillation Project with Emulsion-Tracking Apparatus, sent neutrinos from a particle accelerator at CERN outside Geneva, Switzerland, racing some 450 miles to a cavern in Gran Sasso, Italy. The neutrinos arrived roughly 60 nanoseconds faster than light.

“The OPERA measurement is at odds with well-established laws of nature, though science frequently progresses by overthrowing the established paradigms,” CERN said in a statement. “For this reason, many searches have been made for deviations from Einstein’s theory of relativity, so far not finding any such evidence. The strong constraints arising from these observations makes an interpretation of the OPERA measurement in terms of modification of Einstein’s theory unlikely, and give further strong reason to seek new independent measurements.”

“It is rather hard to imagine what it means if it is true,” said Jenny Thomas, a professor at the University College of London who is now working at the Fermi Lab. “The speed of light being a constant and the maximum speed possible is one of the cornerstones of physics, so it would be much more likely it is some mundane explanation to do with the experiment.”

In 2007, scientists at the Fermi Lab also registered neutrinos traveling faster than light, but the difference was within the error rate of the experiment. Their equipment and methods were not as precise then as they are now at CERN. But the scientists at Fermi are now going to try again and see if they can duplicate CERN’s findings.

“I believe it will be months and years of happy investigative thought and quite a bit of head banging as well,” Plunkett said. “As theoretical physicists try to understand how they would deal with such a thing and we being to work out the details of how to make a definitive yes, no check.”

Image courtesy CERN.