Space travel. Right now we are on the cusp of having incredible new launch capabilities. SpaceX’s Starship is the most well developed example, but there are others maybe a few years behind. But when you listen to people talk about the opportunities that will open up they don’t really seem to get it. They’ll talk about satellite constellations, or space tourism, or even mining asteroids, but that’s just small potatoes. Once we have a little experience with industry in space you’ll be looking at exponential growth with practically unlimited resources in an environment where energy is free and space is limitless. Will governments be able to enforce laws in a theater a quadrillion times the size of the earth? What politics or institutions would or could govern such an environment. There are so many questions about how things will unfold and nobody is an expert. Nobody has anything but almost baseless guesses. I can’t even tell you if humans will play a major role or if it will be almost entirely robotics. Musk might be thinking about Mars colonies, but what actually comes next isn’t up to him. It’s going to be driven by economic forces, technological ability, and quite possibly geo political interests that nobody fully understands. It’s gonna be wild.