My first Magazine Sky & Telescope - 01.2019 | Page 25

MAKING WAVES This artist’s concept shows two black holes en route to merg- ing. Their inspiral creates ripples in the fabric of spacetime that propagate out from their location at the speed of light. Astronomers are watching dozens of cosmic timepieces for signs of spacetime ripples passing through. sk yandtele scope.com • JA N UA RY 2 019 23