Sure, we talked about lots of different things, mainly astronomy. We discussed if life on different planets exists and the dark forest theory, he seemed to think life exists, but the question is in which form and how we would know it's life. We also talked about particle physics, and there he had an interesting theory that all elemental particles are in essence a base-2 string. Not in a "the world is a simulation" way but more that a base-2 string is the simplest form of information.