Neutrons, rotating black holes, and a galactic PeVatron at the center of the Milky Way

Galactic black holes are cosmic mitochondria, powerhouses of the universe. Most of the energy these supermassive black holes produce comes from the material surrounding them: superheated plasma in their accretion disks interacting with tremendous magnetic fields. But there is a more direct way to extract energy from a black hole. It's known as the Penrose process, and a new study asks whether we could discover a signature of this process.