There is an idea that our visible universe is a small particle, and there are several more around this particle, and together we are an atom of another substance in another world
There are two possibilities: either we are alone in the universe, or we are not.
Both are equally frightening.
An illustrative example, by the way, can be found in our history. For example, the Pioneer record, which was sent along with the Pioneer-10 and Pioneer-11 probes to other civilizations. Many scientists on Earth have failed to decode it back.
And speaking of your question, there is the so-called "Zoo Hypothesis". And a bunch of other hypotheses
And all equally likely to be correct. And this is all due to the fact that the universe has no end