If you’re reading this article, you probably have some knowledge about particles on a molecular level. To recap, there are atoms, and inside atoms are electrons, protons, and neutrons -- the three elementary particles. You’ve been taught in school that these are particles that can’t be changed; that they will always exist everywhere no matter what. Although in essence this may be true, there are other conjectures which have recently sparked interest in the world of science.
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What if everything you thought you knew about the nature of the universe was false?

Here we introduce String theory.

Essentially, String theory is the idea that point-like (0-dimensional) particles (of particle physics) are completely replaced by a one-dimensional “string”. These strings are supposedly what everything in the universe is composed of.

You may be wondering, if we already have a solid understanding of particle physics, why does String theory exist?

Over 100 years ago, humans thought that the atom was the smallest unit of matter. We were (and still are) able to observe atoms in their true form, using technology. As time passed we were able to discover even smaller, subatomic particles (protons, neutrons and electrons). The problem was, we aren’t able to directly see these particles.

The process of seeing an object requires light. This light hits the surface of the object, and gets reflected into your eyes. With elementary particles, the electromagnetic waves that we use to see, are too big to touch them. We could try to manipulate these waves to have more and much shorter wavelengths, but more wavelengths means more energy, and when this amount of energy comes into contact with elementary particles, we alter them. So, we currently cannot precisely see or measure any particle smaller than an atom.

String theory describes the notion that the universe is made of one-dimensional strings which vibrate and interact with each other. On a larger scale, a string would just look like a particle, with a charge, mass, and other properties, determined by the vibrational state of the string, a concept that is theoretically much easier to emulate than particle physics is.

This is the reason behind why String theory exists.
However, this theory itself does have many flaws and debatable logic behind it too -- to be discussed in another article.