Disturbed black holes behave exactly as predicted by Albert Einstein’s theory of general relativity. They determined that the two original black holes had a total surface area of 240,000 km2, while the newly formed black hole covered about 400,000 km2. “When two black holes merge to become one, it causes the final, larger black hole to vibrate like a struck bell, ringing out into the cosmos. “By analysing the frequencies of these gravitational waves created by the black hole merger, we have detected the strongest and cleanest black hole ‘note’ we’ve ever heard. Since then, the gravitational-wave-hunting LVK Collaboration has captured a total of about 300 black hole collisions — as well as a handful of binary neutron star and black hole-neutron star mergers — with scientists now detecting a black hole merger roughly once every three days.