Unified Field Theory

           In 1928, Einstein began work on a Unified Field Theory.   Unified Field Theory seeks to unify the four known forces (strong, weak, electromagnetic, and gravitational)  by a set of general laws.  These four forces are known to control all matter interactions.  Gravitation, electromagnetism, the holding together of atomic nuclei (strong force) and slow nuclear changes (weak force).  Unified Field Theory sought to prove that all phenomena were caused by an underlying unity.

            Upon completion of his Theory of Relativity, Einstein was led to the assumption that a unifying theory could be found to link the gravitational and electromagnetic forces.  During the final 30 years of his life, Einstein tried, without success to develop a theory that would represent forces and particles with fields (particles, in Einstein’s view, would have been regions of high field density).

            Some progress has been made in the creation of a Unified Field Theory since Einstein’s death.  In 1968, Steven Weinberg and Abdus Salam succeeded in unifying the weak force and the electromagnetic force.   According to the theory, the particles exchanged in the electromagnetic and weak interactions belong to the same family of particles.   Physicists are trying to combine this electroweak theory with the strong force to make a Grand Unification Theory.  Efforts to combine all four forces into what is called a Supersymmetry Theory have thus far fallen short.