Well, once material falls in, there's no going back, but the black hole's extreme gravity creates the perfect environment for generating energy just outside its boundary, or horizon. (discovermagazine.com)
This behavior aligns with Albert Einstein's predictions about extreme gravity near rotating black holes, published in his famous theory of general relativity. (sciencedaily.com)
What happens when extreme gravity pierces the fabric of space - time? (newscientist.com)