Although a complete mathematical formulation of M-theory is not known, the general approach is the leading contender for a universal "Theory of Everything" that unifies gravity with other forces such as electromagnetism.
[1][2][3] In the early years of the 20th century, the atom – long believed to be the smallest building-block of matter – was proven to consist of even smaller components called protons, neutrons and electrons, which are known as subatomic particles.
It showed how all the different subatomic particles known to science could be constructed by hypothetical one-dimensional "strings", infinitesimal building-blocks that have only the dimension of length, but not height or width.
Nevertheless, some physicists are drawn to M-theory because of its degree of uniqueness and rich set of mathematical properties, triggering the hope that it may describe our world within a single framework.
One feature of M-theory that has drawn great interest is that it naturally predicts the existence of the graviton, a spin-2 particle hypothesized to mediate the gravitational force.