Fundamental Forces The fundamental interactions , also known as fundamental forces , are the interactions that do not appear to be reducible to more basic interactions. There are four fundamental interactions known to exist: the gravitational and electromagnetic interactions, which produce significant long-range forces whose effects can be seen directly in everyday life, and the strong and weak interactions , which produce forces at minuscule, subatomic distances and govern nuclear interactions. Some scientists hypothesize that a fifth force might exist, but these hypotheses remain speculative. Each of the known fundamental interactions can be described mathematically as a field . The gravitational force is attributed to the curvature of spacetime , described by Einstein's general theory of relativity . The other three are discrete quantum fields , and their i...