For the ancient Greeks, there was an indivisible element they called the atom. Later, we discovered that atoms are composed of subatomic particles and that these, in turn, are also composed of even smaller elements. These discoveries, revealing that “the indivisible was divisible,” continued until String Theory proposed that the particles making up the Universe might take the form of vibrating strings, with each vibration determining the characteristics of a particular particle.

According to astrophysicist Stephen Hawking, the different oscillations of a string give rise to various masses and force charges, which are interpreted as fundamental particles. String Theory led scientists to imagine that Einstein's long-held dream of unifying all theories was now within reach. Learn more in the theory below.