The existence of a multiverse

One of the topics Hawking tinkered with towards the end of his life was multiverse theory – the idea that our universe, with its beginning in the Big Bang, is just one of an infinite number of coexisting bubble universes. Hawking wasn’t happy with the suggestion made by some scientists that any ludicrous situation you can imagine must be happening right now somewhere in that infinite ensemble.

In his very last paper in 2018, Hawking sought, in his own words, to “try to tame the multiverse”. He proposed a novel mathematical framework that, while not dispensing with the multiverse altogether, rendered it finite rather than infinite. But as with any speculation concerning parallel universes, we have no idea if his ideas are right. And it seems unlikely that scientists will be able to test his idea any time soon.

“Hawking sought to try to tame the multiverse”