In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other.

String theory is one of the most famous ideas in modern physics, but it is also one of the most confusing. At its heart is the idea that the fundamental particles we observe are not point-like dots, but rather tiny strings that are so small that our best instruments cannot tell that they are not points.

String theory is a framework that physicists use to describe how forces usually conceptualized on a gigantic level, like gravity, could affect tiny objects like electrons and protons.

String theory replaces all matter and force particles with vibrating strings that twist and turn in complicated ways and which look like particles from our perspective.

The theory envisions that a string undergoing a particular mode of vibration corresponds to a particle with definite properties such as mass and charge.