I have a setting in which there are nine planets in star systems scattered across the galaxy, linked together by some being or intelligence capable of manipulating spacetime. The current inhabitants of these planets have only cursory knowledge of how this came to be, but this arrangement is central to the setting; their technology and spaceflight capabilities are perhaps one or two centuries further along than our own, but they must be able to travel between these planets, even though they are separated by many light years.
The only way this arrangement is possible is through a wormhole network. I considered how wormholes are typically imagined, as spherical regions of space, which would be placed in these planets' star systems. But I'd like to take it a step further; I want the inhabitants to be restricted to the nine planets (and their moons). In other words, the planets will exist (or appear to exist) in the context of their star system and neighboring planets, but when the inhabitants cross a certain threshold (possibly the Hill radius?), they are transported to one of the other linked planets, or more likely a central hub linking all nine nodes. This cannot be achieved by wormholes as they are typically imagined. This is where the dilemma arises.
I have looked into various topics that may have the pieces necessary in explaining my setting, such as:
- Non-orientable wormholes / Alice handles
- Thin-shell wormholes
- Manifolds; embedding; immersion
- Brane cosmology
- "Bubble universes"; multiverse theory
I must admit, however, that these topics quickly become extremely technical, and I have trouble applying them for my purposes.
Could the wormhole connection take a different shape than a sphere that is accessed from the outside? Could it be in the form of a membrane, somehow anchored to a planet's gravity well, that is accessed from inside? Could it somehow be embedded in a more complex topology, possibly a higher-dimensional manifold? I know that any solution will be theoretical, and I don't need a rigorous mathematical formula to explain it for the purposes of my story. But I do want there to be some logic behind it, rather than going the route of a magical portal system.
Is there a wormhole topology that makes sense for the setting I've described, in a way that allows the planets to locally appear to be in orbit around their stars, while being linked to the other planets? Note: If the solution requires that the planets lay in separate parallel universes, or something along those lines, I'm quite willing to accept that.