Scientists Suggest Dark Matter May Be Made Up Of Primordial Black Holes

Could dark matter consist of primordial black holes, as numerous as the stars? It’s an old, improbable idea, but it made a Lazarus-like comeback a year ago, when the discovery of gravitational waves suggested that the cosmos abounds with unexpectedly heavy black holes.

With decades-long searches failing to find the hypothetical dark matter particles that theorists have favored, physicists are turning to more radical ways of explaining the universe’s missing mass. “It’s a nutty idea,” says Marc Kamionkowski, a theorist at Johns Hopkins University in Baltimore, Maryland, whose team made the case for black hole dark matter here last week at a meeting of the American Physical Society.