The Differential Topology of Gravity

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Gravitation acts like an astigmatic lens. If you just go through empty space, then it focuses one way and expands out in the other direction. This is what leads to spaghettification if you fall into a black hole. So I knew about these things by thinking about these focusing effects and so on. And it was using this kind of argument together with topological arguments that you could see if you reached a point of no return and that was a critical point which would make gravitational waves irreversible. Really it gets to a point where you don't know what happens, it sort of stops, space time gives up.

Sir Roger Penrose has had a remarkable life. He has contributed an enormous amount to our understanding of general relativity, perhaps more than anyone since Einstein himself -- Penrose diagrams, singularity theorems, the Penrose process, cosmic censorship, and the list goes on. He has made important contributions to mathematics, including such fun ideas as the Penrose triangle and aperiodic tilings. He has also made bold conjectures in the notoriously contentious areas of quantum mechanics and the study of consciousness. In his spare time he's managed to become an extremely successful author, writing such books as The Emperor's New Mind and The Road to Reality. With far too much that we could have talked about, we decided to concentrate in this discussion on spacetime, black holes, and cosmology, but we made sure to reserve some time to dig into quantum mechanics and the brain by the end. See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.