It was September 14, 2015, 1.50 a.m. at Hanford in Washington state, US, and 3.50 a.m. at Livingstone in Louisiana state. It was 3:20 p.m. in India. None of us knew that the earth shook. Yes, the earth shook. But it was not an earthquake; it was the ripples in spacetime itself, i.e. gravitational waves, caused by the merger of two black holes some 1.3 billion light years away. We could not feel the tremor, but thankfully two instruments made for this purpose detected the events. Scienti