M-theory
To understand M-theory one must first have some knowledge of string theory. For hundreds of years, scientists have thought that the simplest objects in the universe are points, like dots. String theory says that this is wrong and that the simplest objects in the universe are shaped like pieces of string. These strings are so small that even when looked at very closely they look like points. Each basic particle is created by the strings vibrating in different patterns. The reason scientists had not thought of this idea for so long is that strings are much harder to work with than points. They seem to break such rules as causality and special relativity, which says that information cannot travel faster than the speed of light.