New theory could finally make ‘quantum gravity' a reality... and prove Einstein wrong

A united Theory of Everything is the 'Holy Grail of physics'

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The difficulty in creating a theory of 'quantum gravity' is that the two ideas look at the Universe at completely different scales.

Quantum mechanics looks at the smallest scales of the particles that make up atoms. Physicists have used it to create the Standard Model, which gels together three of the fundamental forces that govern our Universe: electromagnetism, the strong force (which holds protons and neutrons together) and the weak force (responsible for radioactive decay).

The fourth fundamental force is gravity, as laid down by the laws of General Relativity written by Albert Einstein. This thinks of gravity as the warping of spacetime. Large masses and highenergy objects distort spacetime as they move through it, and affect the objects around them. It controls everything that happens in our Universe, from planets to stars and galaxies. And it refuses to play nicely with the laws of quantum mechanics.

A TALE OF TWO THEORIES

One of the biggest problems is that gravity is a 'deterministic classical' theory. Its laws state with certainty what the consequences of an action will be. Drop a ball, and gravity means it will definitely fall to the ground.

Quantum theory, however, is probabilistic in nature. It doesn't predict the precise outcome of a situation, only the likelihood of it happening.

“These are challenging to combine,” Dr Mikko Partanen, lead author of a study published in Reports on Progress in Physics told BBC Science Focus. “Attempts to apply quantum theory in the presence of gravitational interaction have led to many nonsensible results.”