|World's First Observed Neutrino In A Hydrogen Bubble Chamber|
A neutrino is a subatomic particle that does not carry electrical charge and do not readily interact with matter. Scientists say billions of neutrinos pass through our bodies every second, never to colloid with another atom in our bodies. Neutrinos had been theorized to exist in 1930, but were not detected until 1956. The first detection of neutrinos won the scientists a Noble Prize. So why care about neutrinos? Scientists say without neutrinos the sun wouldn't shine. For something that is hard to detect and doesn't interact easily with matter, it is a pretty important particle.
So back to the question who cares if a neutrino went faster than the speed of light? The answer to this is more philosophical, perhaps even theological, than scientific. The short and simple answer is that according to Einstein's Theory of Relativity, the speed of light is the ultimate speed limit in order to protect causality. According to Einstein, if something travels faster than the speed of light, it does not just arrive some place faster than light, it in fact time travels into the past. If Einstein's theory is held to be true or to represent reality, the implication of a neutrino traveling faster than the speed of light is that the neutrino arrived at the detector before it was sent -- time travel. A neutrino traveling faster than the speed of light is akin to seeing a window shatter from a brick passing through it, while the brick is still in your hand unthrown -- at least if Einstein's Theory of Relativity is accepted.
This also explains why so many scientists are certain that there must be a mistake in the measurements. Causality must be protected -- something cannot happen before an action that causes it occurs (the brick cannot break the window before it is thrown). Therefore, it is impossible for the neutrino to go faster than the speed of light. At the heart of the issue, which at first appears to be "scientific," is a deep philosophical (and theological) discussion on causality and the nature of time. These are both philosophical ideas that have been debated at least since the ancient Greek philosophers (if not earlier). While physicists are good at mathematics and detecting subatomic particles, physicists usually are not known for their study of philosophy or theology. Questions related to the nature of time or causality might be better left to philosophers and theologians than to physicists who excel at measuring the physical world but do not necessarily excel at describing the nature of a thing, or its essence.
Science in the late 19th and throughout the 20th century has assumed that the measuring of a thing gets at its essential nature. For instance, before the late 19th century, philosophers discussed the nature of time. At the end of the 19th century and throughout the 20th century, scientists became very skilled at building machines to measure time. For instance, in August of 2011, British scientists that they had developed the most accurate atomic clock in the world, one that would loose a billionth of a second every two months. Einstein's Theory of Relativity predicted and experiments of particles traveling near the speed of light and of atomic clocks in earth's orbit (the GPS system) have demonstrated that these atomic oscillations slow down as an object speed increases. In essence, the faster the clock is traveling, the slower it runs. Scientists have assumed that the slowing of the clock is in fact a slowing of time. According to Einstein's Theory of Relativity, if the "clock" were to hit the speed of light, the clock, that is the atomic oscillations, would stop. Hence, time stops. Once again, the assumption is that the movement of the clock corresponds to time itself. Rather, Einstein predicts that time itself is relative and that there is no universal time that governs the entire universe. These big questions are more philosophical than scientific.
Have no fear. If the faster than light neutrino experiment results are upheld, causality will be protected and there will be no time travel. Physicists will simply redefine the cosmic speed limit as the newly discovered faster than light neutrino, or develop other theories to explain how the neutrino travelled faster than light could -- such as jumping through another dimension we did not previously know to exist.
This raises the larger question are scientists actually measuring what they think they are? Does the speed of light in fact protect causality? Does faster than light travel equal time travel? These are really philosophical and theological questions rather than scientific questions. So let's have physicists do physics and leave metaphysics alone.
In any case, the paper published by the OPERA scientists on faster than light neutrinos is given below.