The question of what is beyond the universe is a complicated one, and there are many theories but no definitive answer. Here are some of the most popular theories:

• There is nothing beyond the universe: By definition, the universe is everything, so there is nothing external to it for it to expand into. If you take the universe to mean literally all the things that could possibly exist in all of space and time, then there cant be anything outside the universe.

• The universe is infinite: If the universe is infinite, there is nothing beyond it, by definition. Some astronomers think space outside of the observable universe might be an infinite expanse of what we see in the cosmos around us, distributed pretty much the same as it is in the observable universe.

• The universe is part of a multiverse: Some believe that the whole of our universe could exist in a small “bubble” in the midst of a vast array of other bubbles. Theorists call this a “multiverse.” These universes can come into contact with one another—gravity can flow between these parallel universes, and when they connect, a Big Bang like the one that created our universe could occur.

• The universe is expanding into something: Another theory is that we are creating space as our universe expands. Outside this expansion lies a higher dimensional space-time universe which we are unfolding into. Since it is higher dimension, we cannot see, detect it, or comprehend it.

• We cannot know: Finally, it is possible that we simply cannot know what lies beyond the universe. Our view is so small and the universe is so vast that we may never be able to answer this question.

In conclusion, the question of what is beyond the universe is a complex one, and there are many theories but no definitive answer.