A team of atomic scientists may have observed matter traveling faster than the speed of light. If true, that finding changes everything.
LOGO of CERN, the European Organization for Nuclear Research
The team at the European Organization for Nuclear Research (CERN) ran a joint experiment with the Gran Sasso laboratory in Italy. The CERN team fired 15,000 beams of neutrinos toward Gran Sasso, 500 miles away. The neutrinos reached Gran Sasso 60 nanoseconds faster than they should have.
To put that in perspective, 500 miles is about 2.4 light-milliseconds away. Compared to this, 60 nanoseconds is one part in 250 thousand.
That might not seem significant. To prove this finding, the ones measuring the time must be exquisitely precise. Scientists who ran an earlier experiment of that kind at Fermilab in Chicago got a finding like this—but had to reject it. The reason? They could not measure time precisely enough, so the finding was well within the margin for error. The Fermilab team will now repeat their experiment, with clocks precise enough to measure time differences on the order of one part in 250 thousand—or less.
If that experiment—and another experiment in Japan—yield the same result, it would mean that the neutrino—a particle of matter—exceeds the speed of light.
Definition of the speed of light
The speed of light in a vacuum is the speed of any electromagnetic wave. James Clerk Maxwell first worked out the equation that gives the speed of light. The problem: that speed depends only on two other constants that describe the electrical and magnetic properties of a vacuum (or of whatever other medium light might travel through). That speed does not depend on the frame of reference of the light.
For decades since Maxwell wrote his paper, scientists wondered what frame of reference was appropriate for the speed of light. Would it be the lamp? The eye of the beholder? Or some absolute medium in space—the aether, as men once called it? In 1905, Albert Einstein said that if the speed of light did not depend on frames of reference, then it was the same in all frames of reference. So Einstein gave the speed of light its trademark symbol: c, for constant.
What a constant speed of light means
This implies that whether the lamp is keeping the same distance from the beholder, or moving toward or away from him, does not matter. The speed of light is the same. That makes little difference on the scale of ordinary events. But if, say, a train moved toward a grade crossing at an impossible speed, then the light from its headlight would move at the same speed as the light from any track signal that it passed. That would be equally true for the engineer as for anyone walking along the track.
So if the speed of light is the same, then time, length and mass are not the same, at least not along the way that the train is moving. To any stationmaster that the train passed, the train would be shorter when in motion than when stopped. The engineer’s clock would also run more slowly than the stationmaster’s clock, and the train would also be noticeably heavier. If the train were ever to run at the speed of light, then it would be flatter than a pancake, the engineer’s clock would stop completely, and it would be infinitely heavy.
Einstein, in working out his Special Theory of Relativity, looked at it another way. The only thing that could travel at the speed of light would be an object with no proper mass, something that could never exist at rest. Only light, and maybe neutrinos, would qualify.
Neutrinos are the fastest particles of matter known to man. No one has ever seen a neutrino seeming to approach with a left-handed spin. That’s because nothing can ever catch up to a neutrino. So if any particle could fly at the speed of light, neutrinos would.
The CERN/Gran Sasso finding means that neutrinos have flown faster than light. So in theory, the neutrinos have reached their targets before anyone standing near them could watch anyone fire the guns that sent the neutrinos on their way. And this assumes that the space between the guns and the targets were a vacuum!
What faster-than-light travel means
If the CERN findings are correct, then either:
- Neutrinos do not slow down in a gravity field, as light does. (Einstein predicted that later, and other scientists confirmed it.) Or:
- Mankind’s understanding of the universe is incomplete.
The Special and General Theories of Relativity have held up too well for scientists to throw them out completely now. But they might have to regard relativity as a special case, one that works well only on the scale of experience on earth, and in the solar system. (The finding might have a practical use: a new form of communication that would let rocket-probe controllers send orders out to their probes, and get data back, faster. Even an interstellar mission would be more feasible than before.)
This could mean that every model of the cosmos, and its origin, is more flawed even than creation scientists have long suspected. This goes beyond the invention of the concepts “dark matter” and “dark energy” to save the Big Bang theory. If neutrinos in particular fly faster than light, then astronomers must start now to observe of incoming neutrinos, to make more accurate maps of the far reaches of space. Even that will not stop a career-breaking controversy perhaps as bitter as the trial of Galileo.