According to some theories, the universe we experience is just a four-dimensional surface in a ten- or eleven-dimensional space. The movie Interstellar gives some idea of what this would be like. We wouldn’t see these extra dimensions because light wouldn’t propagate through them, but only through the four dimensions of our universe. Gravity, however, would affect the extra dimensions and would be much stronger there than in our universe. This would make it much easier for a little black hole to form in the extra dimensions.
