Just something which puzzles me till now.
How does one defines the edge of our universe?
What's considered inside and what's considered outside?
If there is a outside, what does this outside contains? Vacuum?
If vacuum is outside of our universe, why should it be considered not part of our universe then?
If the vacuum outside of our universe is considered part of our universe, then what's truly outside? Nothing, not even vacuum? Or is vacuum not truly empty?
Anyway, just some rhetorical questions that boggled my mind.