It consists of a definitive theory, a unique equation that answers all the fundamental questions of the Universe.
The Theory of Everything or Unified Theory was Einstein's unfulfilled dream. To this he dedicated with passion the last 30 years of his life. He did not succeed, and today he continues without discovering.
The theory of everything must explain all the forces of Nature, and all the characteristics of energy and matter. It must solve the cosmological question, that is, give a convincing explanation to the origin of the Universe. It must unify relativity and quantum, something so far not achieved. And also, it must integrate other universes in case there are any.
It does not seem easy task. It is not even known if there is a theory at all in Nature. And, if it exists, if it is accessible to our understanding and our technological limitations to discover it.
Einstein believed that such a theory exists or should exist. For him, the Universe is something harmonic and orderly, in which everything is related and has a purpose. He believed in the beauty of mathematics and the Universe. It followed the traditional vision of ancient Greek mathematicians and philosophers. That is why he did not accept the chaos of quantum, newly discovered at that time. For Einstein, "God does not play dice." Einstein was left alone in his search for a theory at all. During the last years of his life he distanced himself from his colleagues so much that they ridiculed him and took him as crazy.
Previously, other laws of Nature were unified. In the 19th century, Maxwell unified the electric and magnetic forces in electromagnetism. At the beginning of the 20th century, Einstein's relativity unified space and time, and later the space time with gravity.
What no one has been able to unify yet is relativity with quantum. Relativity is the law of the very great, of the stars and galaxies. Quantum rules in the smallest, in subatomic particles. But sometimes they appear together, as in black holes or in the Big Bang, and physics has not yet been able to reconcile them.
The standard model, which dominates physics today, managed to unify three of the four fundamental forces of Nature: electromagnetism, strong nuclear force and weak nuclear force. All three adapt to both relativity and quantum. The problem is in the fourth fundamental force: gravity, which remains incompatible with quantum.
Today, string theory seeks to fulfill Einstein's dream. It is the main candidate for a theory of everything. A variant of string theory, the M theory, believes that it can unify gravity. For the M theory, gravity would not be a force but a type of particle caused by a special vibration of the strings. This elementary particle would be a boson called graviton. But to date it is just an unproven theory.
If there is a theory at all, or not, it remains one of the greatest mysteries of the Universe. Will we have to wait much longer?
|◄ Previous||Next ►|
|Schrödinger's cat paradox||Quantum principles|