Black Holes

For the third time in less than two years, physicists have detected billion-year-old ripples in the fabric of space-time. The new recording, like the two others before it, was made using the Laser Interferometer Gravitational-Wave Observatory (LIGO)...

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...