It’s one of the most brilliant, controversial and unproven ideas in all of physics: string theory. In many regards, string theory is the best contender for a quantum theory of gravitation, which just happens to unify at the highest-energy scales. A year ago, the top living string theorist, Ed Witten, wrote a piece on what every physicist should know about string theory. So you can get a quantum theory of gravity in spacetime from string theory. The biggest news about string theory is that it can give you a working quantum theory of gravity.

Source: Forbes November 25, 2016 20:45 UTC