String theory envisions a multiverse in which our universe is one slice of bread in a big cosmic loaf. The other slices would be displaced from ours in some extra dimension of space.

Energy is the ultimate convertable currency.

Most scientists like to operate in the context of economy. If you don't need an explanatory principle, don't invoke it.

When I give this talk to a physics audience, I remove the quotes from my 'Theorem'.

Black holes provide theoreticians with an important theoretical laboratory to test ideas. Conditions within a black hole are so extreme, that by analyzing aspects of black holes we see space and time in an exotic environment, one that has shed important, and sometimes perplexing, new light on their fundamental nature.

There may be many Big Bangs that happened at various and far-flung locations, each creating its own swelling, spatial expanse, each creating a universe - our universe being the result of only one of those Big Bangs.

But if you think about a practical implication of enriching your life and giving you a sense of being part of a larger cosmos and possibly being able to use this [gravitational waves] as a tool in the future maybe to listen not just to black holes colliding, but maybe listen to the big bang itself, those kind of applications may happen in the not too distant future.