Wikipedia says

It appears that space was created in the Big Bang, 13.8 billion years ago

This seems a little off to me: can we say something has been created if there was no before it had already been created?

The visualizations often seen of the Universe growing as a bubble into nothingness are misleading in that respect. There is no reason to believe there is anything "outside" of the expanding universe into which the Universe expands.

Neither do I understand this on wikipedia either: it assumes that nothingness is something outside what exists. Nothing is not a ham sandwich.

Anyway my actual question is: can space be created and destroyed - or does an expansion or crunch leave the extent "space" itself the same?


Can space be destroyed?

I can only give an opinion here, not some authoritative answer. But my opinion is based on Big-Bang cosmology and general relativity, so hopefully it isn't total junk.

We have evidence that the universe is expanding, and this evidence looks pretty good. When we project backwards by 13.8 billion years, we surmise that all the galaxies and the space they're in, was as the same place. You can even read how the universe was the size of a grapefruit. Now, I'm not sure that the universe was ever the size of a grapefruit, but I am sure that space expands. Not just because of big bang cosmology, but because of the nature of space. See the stress-energy-momentum tensor? See this picture?

enter image description herePublic domain image by Maschen, based on an image by created by Bamse see Wikipedia

See that shear stress? Einstein's stress-energy-momentum tensor treats space like some kind of gin-clear ghostly elastic! And see that energy-pressure diagonal? A gravitational field is something like a region of space where there's an energy-pressure gradient, where we say spacetime is curved and refer to the rubber-sheet analogy. And get this: if you took away all the gravitational fields from all of space, you'd take away all the pressure gradients. But not the pressure. So space has this innate energy-pressure, so it expands like a stress ball when you open your fist. Now think about this: the stress ball is made out of rubber. Is rubber created when you open your fist? No. And nor is energy. Energy is the one thing we can neither create nor destroy, and it seems to be intimately related to what space is. But nevertheless the stress-ball does get bigger as the pressure reduces, so it's reasonable to say space is "created". Therefore I think it's reasonable to assert that you can reverse this. How do you do it? By increasing pressure, any way you wish, at any scale you like. So how do you "destroy" space?

Just squeeze a stress-ball.

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