To add to my previous question. Can a black hole be a wormhole or can a wormhole exist within a black hole? The result I want to get is this:

* *You enter a black hole in one part of space and exit from a white hole in a very different part of space. So you travel through space and time across the universe.*

If somebody knows or has any idea of how this could be explained and could work theoretically or better scientifically, please aid me.

Edit: I've noticed in cosmos adventures authors use some kind of vortexes to travel extremely large distances between galaxies. What is this vertex? I couldn't find information about it.