September 24, 2011
What has been discovered?
A fundamental subatomic particle, the neutrino, seems to be capable of travelling faster than the speed of light (that is, the speed of a photon through a vacuum).
Why do physicists believe nothing can go faster than light speed?
At the turn of the 20th century, Albert Einstein used earlier work by the physicist James Clerk Maxwell to show that the speed of light, c, is a fundamental constant and that it is also the maximum speed that anything can travel. In practice, the only things that do travel at this speed are photons (particles of light) moving through a vacuum.
Einstein encapsulated c in his special theory of relativity, which says that the laws of physics are the same regardless of who is observing or experiencing them. To accommodate the invariance of the speed of light, Einstein had to modify Newton’s laws of motion so that time and space became stretchy concepts – as an object moves faster, its size contracts and the time it experiences slows down. Special relativity also leads to Einstein’s most famous equation, E = mc2 (where E is energy and m is mass), which shows that energy and matter are equivalent.