It was rumored that only three people in the world have understood Einstein’s Theory of Relativity. “Anyone who is not shocked by quantum theory has not understood it,” physicist Niels Bohr once said. Quantum theory is now recognized as the most significant advancement in physics of the last century, yet recent experiments in Europe suggest that neutrinos can travel faster than light, in seeming violation of quantum theory and Einstein’s equations.
When Newton first introduced his Law of Gravitation, no time was required for a gravitational interaction to take place. If the sun were to explode, the Earth would instantly “know” and veer off-course, according to Newton. Theoretically, then, it would be possible to send information instantaneously across the universe. But in the early twentieth century, Einstein proposed a new theory. Experiments had recently confirmed that whether the observer was moving or not, light appeared to travel at the same speed. Einstein thus inferred that, for observers in motion, distances must shorten and time must slow down. Moreover, he proposed that objects require more and more energy to increase their speed as they near the speed of light (except for photons, the massless particles of light), and objects would need an infinite amount of energy to accelerate to light speed. Hence, nothing except light would be able to travel at light speed.
While scientists were slow to accept his radical proposals (Einstein’s Nobel Prize was actually for his work on the photoelectric effect, not for his Theory of Relativity), they eventually became the dominant form of physics, and were confirmed when laboratories showed that protons and electrons could not be accelerated to light speed.
This last September, however, Switzerland-based European science consortium CERN measured the time it took neutrinos emitted from its large hadron collider to travel to Italy. According to the New York Times, their results were about 58 nanoseconds faster than light would have travelled. Moreover, a second experiment, designed to rule out a potential problem involving the bursts of neutrinos emitted, produced a time 62 nanoseconds shorter than that of light, seemingly confirming the previous result.
While testing still remains to be done, this experiment could have a far-reaching effect. NASA, for example, is working on sending astronauts to Mars and satellites to Alpha Centauri, the nearest star to earth. If particles can travel faster than light, then Einstein’s equations might be mere approximations of a more general law of physics, just as Newton’s equations are approximations of Einstein’s laws. NASA may need to use more precise equations when calculating the trajectories of their spacecrafts.
If traveling faster than light is possible, space travel may be easier because there would no longer be a speed limit on objects sent into space. Additionally, information might be able to travel faster than light. Today, cell phones, the internet, and GPS devices use photon exchange to send data, so information travels at light speed. Future technology, however, could use neutrinos to exchange this information. While the difference in speed may not be noticeable on earth, communications with satellites and distant space probes could be greatly expedited.
As exciting as this discovery is, much of the news hype is mere speculation. In fact, one laboratory has disputed the experiment’s results because the neutrinos had the same energy when they left CERN as when they arrived in Italy. If they were indeed traveling faster than light, they should have emitted energy en route and arrived in Italy with less energy than they had when they departed. So, while it may be too early to throw out Einstein’s laws, scientific discovery occurs when data is uncovered that contradicts accepted theory. The experiments at CERN may very well usher in the next revolution in theoretical physics, just as Einstein’s equations did a century ago.
