The Penrose process is a theoretical method for extracting energy from a rotating (Kerr) black hole. It takes advantage of the unusual physics within the ergosphere, a region outside the event horizon where spacetime is dragged by the black hole’s spin.
In this process, a particle enters the ergosphere and splits into two fragments. One fragment falls into the black hole with negative energy (relative to an observer at infinity), effectively reducing the black hole’s rotational energy. The other fragment escapes the ergosphere with more energy than the original particle had, making it possible to extract usable energy.
Although it’s not currently practical for real-world energy harvesting, the Penrose process is important in theoretical physics. It demonstrates that black holes are not entirely “black”—their rotation can, in principle, be tapped as an energy source, and it helps explain how high-energy astrophysical jets might be powered near spinning black holes.