Okay, but what exactly is a gravitational wave and how could they help us crack the conundrum of the black hole code? A gravitational wave is akin to a ripple in space-time. Albert Einstein predicted that massive bodies changing speed or direction generate these gravitational waves. Picture bodies like a pair of black holes orbiting each other. This then creates a gravitational wave that ripples outwards, like a disturbance in a still pool of water after a leaf has dropped onto its surface and ripples are sent across the surface. Like star-crossed lovers, the black holes of two merging galaxies...