An experiment using beams of protons to probe how plasma and magnetic fields interact may have just solved the mystery of how quasars and other active supermassive black holes unleash their relativistic jets.
Let's picture the scene at the heart of a quasar. A supermassive black hole, perhaps hundreds of millions — or even billions — of times the mass of our sun, is ravenously devouring matter that is streaming into its maw from a spiraling, ultra-hot disk. That charged matter is called plasma, and it gets gravitationally drawn into the black hole's surroundings — however, not all of the plasma, which is made from ionized, or electrified, atoms shorn of electrons, is swallowed by the black hole. Indeed, the black hole bites off more than it can chew, and some of the plasma is spat out in jets collimated by the black hole's powerful magnetic field before that plasma gets anywhere near the event horizon, which is basically the point of no return.
