As recently as two years ago, SETI began picking up a different kind of signal — one that scientists can’t explain but believe that it isn’t born out of an attempt to communicate: fast radio bursts (FRBs). These FRBs are massively powerful; so powerful, in fact, that the leading natural explanation scientists can come up with is that they’re from “highly magnetized neutron stars, blasted by gas streams near to a supermassive black hole.” The problem with that explanation is that the bursts aren’t all coming from one specific place, but they are all coming from one specific region of...