Physicians have been dreaming about an equation that unifies the four fundamental interactions in nature in only one “unified field theory”, a single framework for our physics.
Electromagnetic, strong nuclear and weak nuclear forces had already been unified by James Clerk Maxwell’s theories. With his theory of relativity Einstein went even deeper, but he was not able to connect gravity with the other three interactions. Gravity is the weakest interaction in nature – when you hold a pencil, you do it against a whole planet. It almost seems to disappear.
In the beginning of the 1920s, the mavericks Theodor Kaluza and Oskar Klein kept the world in suspense: They extended Maxwell’s and Einstein’s theories by simply adding a fifth dimension. And it worked. Suddenly, the equations worked with the beauty and elegance of mathematics.
They sent a letter to Einstein and he was amazed. Did these unknown guys win the race of the unified field theory?
There was one problem though: Where is this fifth dimension? Could it be that it may exist, but does not influence our perception of space and time? This is why the Kaluza-Klein theory could not supersede the Einstein’s and Maxwell’s theories.
The Kaluza-Klein theory was praised as “beautiful and impressive” by Albert Einstein. Although remaining obscure, it still influences theoretical physics down to the present day.
