In the middle of the 1800′s the first successful (classical)  field theory was developed by James Clerk Maxwell .
In 1820 Hans Christian Ørsted discovered that electric currents exerted forces on magnets.
While in 1831, Michael Faraday made the observation that time-varying magnetic fields could induce electric currents.

Until then, electricity and magnetism had been thought of as unrelated phenomena.

First Field Theory – 1800′s – James Clerk Maxwell proposed for electromagnetism,
Second Field Early – 20th century – Albert Einstein’s proposed general theory of relativity – dealing with gravitation.

The term unified field theory was coined by Einstein, who was attempting to prove that
electromagnetism and gravity were different manifestations of a single fundamental field thus The Unified Field Theory.

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When quantum theory entered the picture, the puzzle became more complex.

The theory of relativity explains the nature and behavior of all phenomena on the macroscopic level (things that are visible to the naked eye);

Quantum theory explains the nature and behavior of all phenomena on the microscopic (atomic and subatomic) level.
Perplexingly, however, the two theories are incompatible. Unconvinced that nature would prescribe totally different modes of behavior for phenomena that were simply scaled differently, Einstein sought a theory that would reconcile the two apparently irreconcilable theories that form the basis of modern physics.

Although electromagnetism and the strong and weak nuclear forces have long been explained by a single theory known as the standard model, gravitation does not fit into the equation.

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Gravitational interaction: a long-range attractive interaction that acts on all particles with mass. The postulated exchange particle has been named the graviton.

Gravitational Anomaly

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