What Is the Universe Occupying as It Expands?

The universe was a tiny, infinitesimally small point like singularity. We have no idea of what came before the big bang. What is the universe occupying as it expands? How do we know? We don't have any observationa evidence. And beyond the universe, what lies we have absolutely no idea. You can ask any scientist you want, you can ask noble prese wingers. There is no way for us to know.