Astronomers have detected their fourth gravitational wave from the merger of two black holes, but this one marks a new milestone.
It’s the first wave picked up by the Virgo gravitational-wave detector in Italy — and the first opportunity to triangulate on its location with the twin detectors of the Laser Interferometer Gravitational-wave Observatory, or LIGO, in Louisiana and Washington state.
The Aug. 14 event, known as GW170814, showed that the ripples in spacetime were emitted by the smash-up of two black holes about 31 times and 25 times as massive as the sun, located about 1.8 billion light-years away. The merger created a single black hole about 53 times the sun’s mass.
Three solar masses were converted directly into gravitational-wave energy, in accordance with Albert Einstein’s famous equation E=mc2.
All that follows the model set by LIGO with its three previous detections since September 2015. The new twist involves folding in the data from Virgo, which started its first full-fledged advanced run in league with LIGO on Aug. 1.
