According to one physical hypothesis, our voluminous world might be a projection from a flat surface. From such a Universe, tiny closed bubbles — baby universes — sometimes pinch off. For a long time, they were thought to be empty, devoid of internal diversity.
It turned out that the information inside them is scattered, like shards of a broken mirror. Each external observer sees only the reflection in their own shard — which means the degree of disorder is high, and the full picture is inaccessible to anyone. This explains why no one can peer into a black hole or grasp what's going on in curved spacetime during collapse.
This approach resolves old paradoxes like the disappearance of information. Hawking was the first to ponder these baby universes, while Maldacena and Susskind built a holographic model.
The idea of tiny universes first emerged in Stephen Hawking's work, but was long considered mathematical exotica.
In science fiction, similar ideas play out in the movie 'Interstellar,' where other dimensions opened up behind a bookshelf.