Binary black hole signal probes event horizon region for first time

If, in space, no one can hear you scream, it seems that you can actually hear the sound of a crash when two black holes collide. Using the loudest gravitational wave ever heard, two Australian scientists and colleagues have been the first to witness the previously elusive "event horizon" at the actual moment of collision, right before all light and sound are swallowed by the newly formed black hole for eternity.