Edge of the Universe – Assume that somehow humans are able to escape the confines of our galaxy, and continue moving in the same direction for an infinite amount of time, at a large fraction of the speed of light. At some point they would reach the end (ignore the cosmic inflation). But as far as we know, there is nothing after the end. Yet continuing, logically, there must be some point where we reach the “edge of the universe.” Scientifically, it is impossible for anything to be infinite (except for irrational numbers and certain mathematical constructs), so what would happen if we reach the edge?

⊕ Three main types of multiverse theories: I – a single space so large that it contains many universe-sized regions, II – a single space containing universe-sized regions with each kind of space, and III – implied by the bare-bones theory of quantum mechanics free from so-called wave-function collapse.

Duplicate Universe – Assume you duplicate our universe exactly, and that there are multiple identical copies of our universe, simultaneously existing. When those other universes were created, would that creation have any effect on our universe, just by merely existing? If that universe did not exist, would our actions/choices be influenced in any way (see Butterfly effect)? If the other copies were in completely different planes that have no way to affect our universe, but we knew about them, would we behave any differently? Even if the universes were identical, would our actions differ between the different alternate universes?

See also:

• https://www.scientificamerican.com/article/multiverse-the-case-for-parallel-universe/
• https://blogs.scientificamerican.com/guest-blog/are-parallel-universes-unscientific-nonsense-insider-tips-for-criticizing-the-multiverse/