# an overview of string theory

## an overview of string theory

General relativity and quantum mechanics take different approaches at looking at how the universe works. Many physicists feel that there must be a method that unites the two. One contender for such a universal theory is superstring theory, or string theory, for short. Let's take a brief overview of this complex perspective.

One string, no particles

Children in elementary school learn about the existence of protons, neutrons, and electrons, basic subatomic particles that create all matter as we know it. Scientists have studied how these particles move and interact with one another, but the process has raised a number of conflicts.

According to string theory, these subatomic particles do not exist. Instead, tiny pieces of vibrating string too small to be observed by today's instruments replace them. Each string may be closed in a loop, or open. Vibrations from the string correspond with each of the particles and determine the particles' size and mass.

How do strings replace point-like particles? On a subatomic level, there is a relationship between the frequency at which something vibrates and its energy. At the same time, as Einstein's famous equation E=mc2 tells us, there is a relationship between energy and mass. Therefore, a relationship exists between an object's vibrational frequency and its mass. Such a relationship is central to string theory.

Limiting the dimensions of the universe

Einstein's theory of relativity opened up the universe to a multitude of dimensions, because there was no limit on how it functioned. Relativity worked just as well in four dimensions as in forty. But string theory only works in ten or eleven dimensions. If scientists can find evidence supporting string theory, they will have limited the number of dimensions that could exist within the universe.

We only experience four dimensions. Where, then are the missing dimensions predicted by string theory? Scientists have theorized that they are curled up into a...