How we closed in on the location of a fast radio burst in a galaxy far, far away

Astronomers have spent the past dozen years hunting for fast radio bursts (FRBs) - flashes of radio waves that come from outer space and last just milliseconds. And after a dozen years of work we still don't know exactly what causes them, only that it must be something very powerful, as they've clearly travelled a long way (billions of light-years).