i just started "Black Holes and Time Warps" by Kip Thorne and also have Hyperspace but havent read it yet. hopefully they will help, thanks

: FWIW, I am reading a book called Hyperspace by Michio Kaku (co-founder of string theory) that proposes just this scenario. Kaku claims space time is actually 10 dimensional and a lot of the "problems" with General Relativity and Quantum Mechanics are solved if you use 10 dimensions. As a result, Black Holes can form bridges into other "dimensions", Einstein-Rosen bridges IIRC.

: Kip Thorne in "Black Holes and Time Warps, Einsteins outrageous legacy" also favours this solution as well.

: This is not to say it is the answer, just that some people are looking at it and proposing novel solutions.

: Yelmalio