Mysterious signals hint that fast radio bursts are more active than we thought.#ScienceAlert

In 2017, astronomers captured a mysterious signal from deep space. For mere milliseconds, it flared brightly in the radio spectrum and fell away, and that seemed to be that. But it wasn't.

Follow-up observations have now revealed the signal repeating, nearly 600 times fainter than that first burst. The repetition suggests these weird radio flares we keep detecting from the cosmos could be more active and more complex than we ever knew.

The flares are called fast radio bursts (FRBs), one of the most bewildering phenomena from deep space. They show up in radio data, huge spikes of electromagnetic energy, as powerful as hundreds of millions of Suns, in a burst only milliseconds in duration.

We don't yet know what causes them, or even where most of them come from; of the over 150 bursts detected, only a handful have been traced back to their galaxies of origin.