For 10 years now, astronomers have been picking-up unusual blasts of high-energy radio waves from distant parts of the cosmos. Each transmission of these “fast radio bursts” has the energy of millions of stars for a fleeting moment, before they disappear in just a fraction of a second. Yet, the source of these powerful signals has scientists baffled.

“We don’t know what type of object is making them,” admits Keith Bannister, an astronomer at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Sydney, Australia. “We don’t have a clue – you click your fingers and they’ve come and gone.”

Astronomers first detected fast radio bursts in 2007, using data from the Parkes radio telescope in Australia, and, so far, more than 20 bursts have been discovered. The mystery of what they are has become one of the hottest topics in astronomy.

This week, research published in the journal Nature has, for the first time, identified where one of these bursts came from. The international team used the giant Arecibo radio telescope in Puerto Rico, along with radio telescopes in Mexico and Europe, to hone in on the source of the signal: a small galaxy 2.5 billion light years away.