When (three) worlds collide

George Mason University professor Shobita Satyapal and PhD student Ryan Pfeifle discuss their discovery of three galaxies with supermassive black holes at their centers that, when they collide, could shake apart matter and light up gravitational wave detectors on earth. It is a fascinating detective story that was reported in the New York Times and on CNN and was aided by the use of several major observatories.