Exploring the Scale of the Universe and Atomic Structures

Stephen Wolfram answers general questions from his viewers about science and technology as part of an unscripted livestream series, also available on YouTube here: https://wolfr.am/youtube-sw-qa

Questions include: In class, we learned that light behaves like both a wave and a particle. How is that even possible? - My teacher said there's no "up" or "down" in space. Why is that, and how do astronauts navigate? - Is the universe as small as it is big? - When will we reach the physical computer chip size limit? I heard in two, three years. I also heard that quantum computer chips are still far away. Is this true? Can you elaborate on it? - How do you expect propagation of light in your model to work out? Will you get frequency-dependent propagation like in a normal elastic solid or independent propagation? - If light has no mass, how can gravity, like from a black hole, pull it in? Doesn't that break the rules?