String theory is a theory that attempts to explain and group the four known fundamental interactions of the universe, which are electromagnetism, strong nuclear force, weak nuclear force and gravitation, into one theory. String theory is a model that attempts to elucidate the phenomena of the universe that are incomprehensible under standard models of quantum physics.
At its foundation, string theory utilizes one-dimensional strings with specific frequencies in place of the standard particles of quantum physics. The formulas stemming from string theory predict a multitude of dimensions, which number 10 or 11 in common string theory models but up to 26 in other versions.
These added dimensions, however, “curl up” within the strings. The average size of these strings is roughly a millionth of a billionth of a billionth of a billionth of centimeter, which is much too small to be seen by current or applied particle physics technology. String theory also refers to another fundamental object known as a “brane.” Branes contain multiple dimensions, and, in some theories, the universe exists within a 3-dimensional brane.
String theory is an evolving science; however, all variations of string theory posit the existence of multiple dimensions and attempt to explain the relationship between gravity and quantum physics. String theory was developed in the 1970s to explain the ambiguities associated with physics and the energy behavior of hadrons.