What is String Theory?

By Ryan L.


What does String Theory mean? Is it some sort of complicated system that requires heavy math? Will it create a black hole and destroy us all? Is it a ball of yarn controlling the universe? Well, it does require some math but as far as the basics are concerned, it is fairly simple. On a guitar, the musical note that is produced by plucking a string varies by how the string is plucked and how much tension is in the string. Similarly, the subatomic particles observed in particle accelerators can be thought of as “excitation modes” of the elementary strings. In string theory, like a guitar, the string must be very tight to become excited. Elementary strings are floating in spacetime, but they are tightened by forces that require lots of math, so I won’t go into details. If string theory is to be quantum gravity, the strings’ length should be around a millionth of a billionth of a billionth of a billionth of a centimeter. This means that such strings cannot, unfortunately, be seen with today’s technology. There are many different kinds of string theory; each one has a different theory of the strings’ shape. Some theories say that the strings are closed loops, others say they float free; some include elemental fermions, subatomic particles smaller than a proton, neutron, or electron. There are 24 different kinds of elemental fermions. There are six quarks, six anti-quarks, six leptons, and six anti-leptons. In order for string theories to include fermions, there needs to be super-symmetry, which means that for every particle that transmits force (a boson), there has to be a fermion (a particle that makes up matter). Currently, super-symmetric particles have not been seen in particle accelerators because they are too large, but in the next ten years, evidence may be found that would make string theory much more realistic.