How quasars shut down star formation in the early universe

Supermassive black holes lurk at the centers of massive galaxies, including our own Milky Way. Puzzlingly, supermassive black holes more than a billion times the mass of the sun appear to exist just a few hundred million years after the Big Bang, when the universe was less than 5% of its current age. As interstellar gas spirals towards such black holes, it accelerates to extreme speeds, heats up, and emits intense radiation across the electromagnetic spectrum, creating a "quasar."