A wormhole basically connects two points in space through a passage made over space. How exactly is the space “folded” to allow for this faster passage?

Question

I understand the fundamental functioning of a wormhole, just take a sheet of paper representing space time, and then fold it to make a hole with a pencil, so there you go, you have a faster passage to the other side of the sheet. However, what I don’t understand is how exactly space-time folds to allow for this passage. I always thought that space was something flat that has leveling according to the mass of stars and planets, so how exactly is it folded up allowing it to pass through a wormhole?

In: Physics

Answer 1

Wormholes are purely theoretical. The maths works for them, but there’s no evidence that the physics works.

Imagine having to find a path between two points on a piece of apper. There may be a whole number of different paths you could take (an infinite number), but given any two paths you can always turn one into the other by nudging it bit by bit.

The idea behind a wormhole would be that there could be paths where that isn’t possible; say if there is a hole in the middle of the paper; you can’t nudge a path that goes around one side into a path that goes around the other side.

And this leads to some interesting results; there are some maths/physics things that don’t change between paths where you nudge one into the other, but might get a different result if you take a path that goes the other side of a hole.

So with our wormhole, there may be two regions of spacetime that are connected via two separate sets of paths (“normally” and “through the wormhole”) and that could be interesting as it could mess with causality, leading to time travel and so on.

But there is no evidence that spacetime is disjointed in this way. It appears to be more like the piece of paper without the hole.

The problem with the “folding a piece of paper” analogy for wormholes is that the paper is a 2-d surface being folded in a larger 3-d space. Whereas spacetime is a 4-d “surface” that isn’t (as far as we know) embedded in some higher dimensional space. So it doesn’t necessarily make sense to talk about “folding” spacetime and trying to join different bits together.