Special Relativity as a Tool

At speeds close to the speed of light in vacuum c relativistic effects become important to consider. Such speeds are normally not encountered in everyday life. However, special relativity is used by scientists when doing calculations in, e.g., particle kinematics, since the particles often have speeds close to the speed of light in vacuum. Also in space physics, special relativity is an important tool.

In 1928, the brilliant English physicist P.A.M. Dirac unified the quantum theory of W. Heisenberg with special relativity in two papers named "The Quantum Theory of the Electron." He received the Nobel Prize in Physics for his contribution as early as 1933. He shared the prize with the Austrian physicist E. Schrödringer, who played a major role in the development of quantum mechanics. At a conference dedicated to the one-hundredth anniversary of Einstein's birth, Dirac said: "Right from the beginning of quantum mechanics, I was very much concerned with the problem of fitting it in with relativity. This turned out to be very difficult, except in the case of a single particle, where it was possible to make some progress. One could find equations for describing a single particle in accordance with quantum mechanics, in agreement with the principle of special relativity. It turned out that this provided an explanation of the spin of the electron." The equation that Dirac was talking about is today known as the Dirac equation and this is the equation describing the dynamics of particles with spin 1/2. Furthermore, Dirac said: " Also, one could develop the theory a little further and get to the idea of antimatter. The idea of antimatter really follows directly from Einstein's special theory of relativity when it is combined with the quantum mechanics of Heisenberg. There is no escape from it."