The waves are produced by mass accelerating through spacetime, so in theory everything produces them—you, me, a black hole, a neutron star. As physicists learn to tune their instruments, more sources of the waves will be within reach. But you&#x27;re right: the odds of detecting a signal this strong and clear right off the bat were low. If LIGO hadn&#x27;t happened to be on when the waves reached it, after 1.3 billion years of traveling through the cosmos, they would&#x27;ve been missed completely. So this was a mix of extraordinary science and extraordinary good luck.