In physics, the fifth dimension is a hypothetical extra dimension beyond the usual three spatial and one-time dimensions. Some scientists have speculated that the graviton, a particle thought to carry the force of gravity, may leak into the fifth or higher dimensions, which would explain how gravity is significantly weaker than the other three fundamental forces. M-theory (the mother of all theories underlying string theories) suggests that space-time has eleven dimensions, seven of which are ‘rolled up’ to below sub-atomic level. Scientist Hooft speculated that the fifth dimension is really the space-time fabric. It has occasionally been stated that the fifth dimension refers to probability, meaning that it is the full amount of possibilities that could happen or, in other words, alternative realities.