Black Holes are among the strangest things in the universe. These cosmic monsters are incredibly massive, but cover only a small region. Classical physics fails to explain what happens inside a black hole.
Einstein’s theory of relativity works well inside a black hole but breaks down at its center. It is commonly believed that a non-rotating black hole has a singularity at its center. Because the singularity is infinitely dense, the known laws of physics cease to exist at this point.
Black Holes commonly form when a really massive star collapses under its own weight. Since stars rotate and the angular momentum must remain conserved, black holes that form through this process must also rotate.
A spinning black hole is different as compared to a non-spinning one in many aspects. A rotating black hole has an additional region surrounding its event horizon known as the ‘ergosphere’. In this region, the space-time rotates abruptly due to the rotational motion of the black hole.
However, since the ergosphere lies outside the event horizon of the black hole, you can still escape this region once you enter it.
A rotating black hole cannot really have a singularity because a point cannot rotate. Instead, rotating black holes have a ringularity. Ringularity or a ring singularity is shaped like a ring and has zero thickness. Thus, a ring singularity is infinitely dense but it can rotate.
Certain theories like the Loop Quantum Gravity theory predict that the center of a black hole could act as a portal to another universe. A non-rotating black hole has a singularity at its center. Anything that reaches the center of a non-rotating black hole would be shredded into pieces by the infinite gravity at that point.
But one can safely reach the center of a rotating black hole as its singularity is in the form of a ring. If the black hole is huge enough, an astronaut or a spaceship can safely enter the event horizon without getting spaghettified and if the black hole is spinning, they can safely reach the center and travel to another dimension or universe.