Has LIGO Actually Proved Einstein Wrong – and Found Signs of Quantum Gravity?

Three physicists have predicted that finding ‘echoes’ of gravitational waves coming from blackhole mergers might be signs of a theory that finally unifies quantum mechanics and general relativity.

Vasudevan Mukunth in The Wire:

Your high-school physics teacher would’ve likely taught you to think about the smallest constituents of nature by asking you to start with a large object – like a chair – and then keep breaking it down into smaller bits. For the purposes of making sense of your syllabus, you probably stopped at protons, electrons and neutrons. That’s a pity because, if you’d kept going, you’d have stumbled upon some of the biggest mysteries of the universe. At some point, you’d have hit the Planck scale: the smallest region of space, the shortest span of time. This is the smallest scale that quantum mechanics can make sense of, and this is where many physicists expect to find the fundamental particles that make up space itself.

If this region – or some phenomena that are thought to belong exclusively to this region – are found, then physicists will have made a stunning discovery. Apart from finding the ‘atoms’ of space, they’d have opened the doors to marrying the two biggest theories of physics: quantum mechanics and the theory of general relativity (GR). The former’s demesne is the small and smaller particles you passed along the way to the Planck scale. The latter’s is the largest distances and spans of time in the universe. And the discovery would be stunning because GR, created by Albert Einstein 101 years ago, doesn’t allow space to have any constituent ‘atoms’. For GR, space is smooth. And it is this fundamental conflict that has prevented the theories from being reconciled into a single ‘quantum gravity’ theory.

But the first signs of change might be here.

More here.