What is the "Unified Field Theory"?

Albert Einstein is best known for his many great accomplishments in physics. He became a household name after publishing "Special theory of relativity" and "General theory of relativity". Most people know him because of that. But only a few knew about him because of his unfinished theory. A theory that would describe the behavior of our entire universe. Now, I am going to tell you what it is.

Four fundamental forces of nature control the behavior of our Universe.

The most commonly known force is Gravity. It keeps us safely attached to the surface of the Earth. Without it, we would be tossed to the outer space by Earth’s rotation and its traveling speed of 30km/s.
It keeps the Moon in orbit around the Earth, the Earth around the Sun, and the Sun around the Milky Way galaxy.

The second most commonly known force is the Electromagnetic force, which is responsible for the electricity we use, and the huge magnet field of the earth. Also, it holds the electrons in orbit around the nucleus, which interacts with other atoms to produce matter.

Electricity and Magnetism are the same. They are just different manifestations of the same force. Thus calling it the Electromagnetic force.

The third force is the Strong Nuclear Force(strongest of the four), which tightly holds the protons and neutrons in place.

The fourth fundamental force is the Weak Nuclear Force which is responsible for the radioactive decay of atoms.

To describe these forces, physicists around the world worked too hard to discover the field equations.

In the 19th Century, a British-born scientist named Michael Faraday introduced fields to the community of physics. by conducting numerous experiments on electricity and magnetism.

In his laboratory, he would visualize a magnet and an electric charge emitting lines of force in all directions, which fills up all the space around it.

To measure the strength and magnitude of these lines of force, he assigned a set of numbers to a particular point. To describe the electric field at that point he assigned another set of numbers. He discovered that a collection of these sets of numbers would completely describe a force at any point in space. Hence, the field was found.

Using Michael Faraday’s theory, James Clerk Maxwell wrote the field equations for electromagnetism in 1860.

In 1915, Albert Einstein wrote the field equations for gravity and published “General Relativity”.

Chinese physicist C.N. Yang and his student R.L. Mills discovered the field equations for the subatomic forces(strong and weak nuclear forces). Yang-Mills field was named after them.

The Unified field theory could explain the nature of all the four fundamental forces as manifestations of the same force.

Einstein spent the last 30 years of his life working on a theory to describe all the four fundamental forces in a single equation. Just like he wrote E=MC² to show that matter and energy are the same, he attempted to prove that all the forces of nature are the same.

But the field equations of the subatomic forces are very different from that of gravitational force. This difference made many scientists argue that the unified theory is impossible.

However, Einstein was confident that it is possible. He worked too hard for it. Unfortunately, he died before finishing the theory. His greatest discovery, the so-called Theory of Everything, was incomplete.

Physicists today are still working consistently to complete the theory. Currently, the Superstring theory appears to be the “Theory of Everything”. But there is no experiment devised to prove it.

We hope that someday in the future someone smart like him (Maybe you) will dedicate their time to complete the theory.