Combining these 2 theories could give us an actual 'theory of everything’

Eight decades have passed since physicists realized that the theories of quantum mechanics and gravity don’t fit together, and the puzzle of how to combine the two remains unsolved.

In the last few decades, researchers have pursued the problem in two separate programs — string theory and loop quantum gravity — that are widely considered incompatible by their practitioners.

But now some scientists argue that joining forces is the way forward.

Among the attempts to unify quantum theory and gravity, string theory has attracted the most attention.

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