In theoretical physics, supergravity (supergravity theory; SUGRA for short) is a modern field theory that combines the principles of supersymmetry and general relativity; this is in contrast to non-gravitational supersymmetric theories such as the Minimal Supersymmetric Standard Model. Supergravity is the gauge theory of local supersymmetry. Since the supersymmetry (SUSY) generators form together with the Poincaré algebra a superalgebra, called the super-Poincaré algebra, supersymmetry as a gauge theory makes gravity arise in a natural way.In simple terms, scientists have identified four basic forces behind everything happening around us. They are electromagnetic force (the source of electricity and magnetism), weak force (which relates to radioactivity), strong force (the force that binds up protons and neutrons within the atom) and gravitational force (the reason why apples fall to the ground and the moon revolves around the Earth). Quantum theory can explain the first three types of forces pertinent to the atomic level, however, for big objects, quantum theory is not applicable. Therefore, the gravitational force is only applied in astronomical science and studies.
These two theories simultaneously may explain all, however, scientists were finding a theory that may explain both quantum theory and theory of gravitation together - a theory of everything. The theory of supergravity revolves around this intention, to establish a theory that is applicable everywhere.