The Special Theory of Relativity
was the result of developments in physics at the
end of the nineteenth century and the beginning of the twentieth century. It
changed our understanding of older physical theories such as Newtonian Physics
and led to early Quantum Theory and General Relativity.
Special Relativity does not just apply to fast moving objects, it affects the everyday
world directly through "relativistic" effects such as magnetism and the relativistic
inertia that underlies kinetic energy and hence the whole of dynamics.
Special Relativity is now one of the foundation blocks of physics. It is in no sense a
provisional theory and is largely compatible with quantum theory; it not only led to
the idea of matter waves but is the origin of quantum 'spin' and underlies the
existence of the antiparticles. Special Relativity is a theory of exceptional elegance,
Einstein crafted the theory from simple postulates about the constancy of physical
laws and of the speed of light and his work has been refined further so that the laws
of physics themselves and even the constancy of the speed of light are now
understood in terms of the most basic symmetries in a four dimensional universe.