E=mc2, arguably the world’s best-known scientific equation, may have suffered a mortal blow last month at the hands of European researchers. The scientists, based at CERN, the main European high-energy physics laboratory, in Switzerland, shot a beam of neutrinos that traveled underground, faster than the speed of light, to their detector in Italy. That had been considered impossible, of course; Albert Einstein’s iconic formula has long decreed that any matter moving faster than the speed of light changes into energy.
Marvin L. Marshak, a professor of physics at the University of Minnesota-Twin Cities, looks forward to testing the CERN result. He runs the world’s only bigger system for exploring neutrinos, a class of extremely tiny particles with properties still not fully understood. Known as the Minos (for Main Injector Neutrino Oscillation Search) project, the system collects neutrinos fired underground from the Fermi National Accelerator Laboratory, near Chicago, to a detector at the former Soudan iron-ore mine, in northern Minnesota. Mr. Marshak wants to see American universities complete an even longer neutrino beam, from Fermilab to a proposed $875-million Deep Underground Science and Engineering Laboratory, known as Dusel, in South Dakota.
Q. Could Einstein and his immensely famous ratio, E=mc2, really be wrong?
A. I’ve convinced myself that this could actually be real. If it’s real, I don’t think it overthrows relativity completely. It could be basically telling us that the constant that Einstein proposed—namely, the speed of light—is not actually the right constant. In other words, when light goes through material, it slows down, and so it could be that what we think is a vacuum is not actually empty. And that’s not that shocking, because for the last 10 years or so we’ve been talking about dark energy. We’ve been talking even longer than 10 years about the Higgs field. So the possibility is that a vacuum is not empty, and therefore, just like light going through glass, light is slowed down relative to neutrinos, which don’t have electromagnetic interactions, and therefore could possibly go a little faster.
Q. But there’s still some ultimate speed limit at which matter converts into energy?
A. Right. There’s still some point. And in any event, for us here, the exciting thing is that we have the only other experiment that could really check this result, and that’s the neutrino beam that goes from Fermilab to northern Minnesota. This is an existing experiment that actually published a result four years ago on this topic, but not with sufficient accuracy to detect the effect at the level that the people at CERN are claiming exists. So now our plan is to improve our timing and go back and look at this with a different setup.
Q. So what does this mean for Einstein and relativity?
A. I don’t want to minimize the impact on physics of this, but personally, I think it could fit into Einstein’s basic framework with some relatively small modifications. What the implications of those modifications are, that would be still significant.
Q. Could this, in a year or five or 10, make a difference on who is studying what at universities?
A. There are a whole bunch of universities involved in the Minos experiment, and all of them are excited. And, of course, it will attract students and interest and all of that kind of good stuff.
Q. Would the new Dusel project help answer any of these questions?
A. The proposed new neutrino beam would be longer, have a higher neutrino intensity and larger detectors. All of these factors mean that Dusel would be even more capable of investigating neutrino-timing effects than any existing experiment.
Q. How worrisome is the prospect of its now falling victim to federal budget cuts?
A. Our political discourse seems focused on immediate solutions to immediate problems. Recent advances in technology have vastly improved the lives of many people worldwide, but current technology is derived from basic science of past decades. My fear is that by thinking short-term in science, we are undercutting advances in technology for future generations.