Well that's an indsight bias if I've seen one. This is the first time I ever read that the "bottom" of a black hole could be a entirely new universe. If there ever "always was" a common hypothesis, it was the wormhole.
There wasn't much substance to it back then, but the idea certainly had been circulated in context of singularities where physics break down. So hypothesis is probably an exaggeration.
raxxorraxor|8 months ago