A: My understanding is that physicists believe the universe may be infinite. I was just reading recently that the evidence suggests that the universe is, indeed, flat and infinite. If that s true, there can be no beyond the universe, at least not in normal, 3D space-time coordinates. I don t understand how it could be infinite, though, if it all started from a point at the big bang, because that would mean that almost all of the universe moved away from that point at infinite speeds.
Outside of normal, 3D space-time coordinates, perhaps there is something a beyond the universe whether it s infinite or not: other universes. Many physicists these days believe in Many Worlds Theory. It s a popular interpretation of quantum mechanics.
Nothingness is nothing more than a concept; it s the lack of anything. Nothing is merely the opposite of something; for example, if I m not holding anything in my hand, you might say there s nothing in it. Nothing doesn t exist except as a concept, the lack of something where something could be imagined to be there.
Nothingness just adds ness to nothing in an attempt to reify it as an actual substance or field or whatever. In practice, it carries the implication that there is nothing at all anywhere, or at least anywhere near. If the universe is finite, going beyond its limits you should find nothing, but that s just another way of saying you won t find anything it s not a way of saying that nothingness is an actual thing or substance.
If you travel beyond the edge of the universe, that is, beyond the extent of all matter in the universe, you ll be in empty space. Empty space isn t a thing, though. It doesn t exist. Space, or spacetime even, is nothing more than a relationship between extant objects. It characterizes how objects interact with each other based on their respective locational properties. You can t detect or interact with space itself, even in principle. We only infer it based on the behavior of extant objects.
To imagine or see empty space is just to imagine or see the absence of any objects with particular locational properties (such as Cartesian coordinates corresponding to wherever you re looking/imagining) where such objects could be otherwise imagined or seen to exist. What you actually see if you re looking at it isn t empty space, of course, it s blackness, or perhaps the light of whatever exists behind the area you re focused on, i.e., the light of objects with locational properties with a greater difference from your own locational properties than the would-be locational properties of any object that could have existed where you re focused on.
I wrote more about this here:
https://myriachromat.wordpres.com/2020/10/29/space-doesnt-exist/
So to be way beyond the edge of the universe, in empty space merely means to have properties of location that reduce interaction with any other matter or energy in the universe to a minimum.
Note that a lot of scientists will tell you that all of space is full of virtual particles, which appear in particle and anti-particle pairs which quickly cancel each other out. This supposedly applies to any space anywhere, so even way beyond all normal matter and energy in the universe, there are supposedly these virtual particles. That doesn t mean that nothingness exists, though, nor does it mean that space exists it would just imply that tiny bits of matter temporarily exist with locational properties not too different from (i.e. not too far away from ) any locational properties an observer can have or imagine.
However, there are also scientists who will tell you that these virtual particles are merely artifacts of the math used in quantum mechanics and don t necessarily represent anything real. I m inclined to agree with them.
Since you asked about my own theory, I believe, or at least it s my pet theory, that all of physicality whether the universe is finite or infinite, whether there is a multiverse or not is just a relatively tiny, tiny point in an an infinitely large spiritual realm, a more obviously panpsychic/pantheistic realm (I say more obviously because I believe this realm is panpsychic/pantheistic too, it s just less obvious) where that which exists is more beautiful and pleasant and behaves less mechanistically than the physical realms. It s even possible that everything that could possibly exist everything imaginable exists somewhere.
Of course, since there s no end to the largeness or variation of patterns and activities in the spiritual realm, it s likely that there are many, many smaller physical realms within it (an infinite number of them, actually), even if they re very far apart, very different from each other, and created by different beings for likely different purposes.