Astronomers accepted that they had detected a real event, but they still thought FRBs were one-offs. The flashes were so intense, even after crossing unfathomable distances in space, that whatever had produced them seemed unlikely to survive the cataclysm. But then astronomers found a repeater, a source of FRBs capable of erupting again and again, sometimes several times in less than a minute.

When astronomers managed to trace an FRB to its home galaxy for the first time, they found a small, lively galaxy, where new stars blinked into existence more than 100 times faster than in our own Milky Way. So FRBs must come from these kinds of environments, they thought. But then astronomers found that some FRBs originated in larger, mellower galaxies too.

“It seems like every time the scientific community converges on a possibility of what FRBs might be, some other observation happens that throws all these speculations out the window,” Kaitlyn Shin, an astrophysics graduate student at MIT who worked on the discovery of the pattern-bearing FRB, told me. “Now all the other theories going forward have to find a way to account for this periodicity.”