For many years, a mysterious signal beamed from deep space has puzzled scientists. First detected in 2007, fast radio bursts or FRBs were thought by some (like physicist Avi Loeb) to be the product of powerful alien civilisations, a signal beamed to Earth from billions of light years away. Others were more sceptical. Now, a team of researchers claims to have figured out the enigmatic emissions once and for all.

Scientists from the Massachusetts Institute of Technology recently published an investigation of FRBs in the scientific journal Nature. In the paper, they say that the explosive radio waves – which last mere milliseconds at most, but contain massive amounts of energy – are likely to come from collapsed stars, AKA neutron stars, or maybe even black holes.

The team focused on one FRB in particular, FRB 20221022A, for the study. This radio signal comes from a galaxy about 200 million light years away. By analysing the way it twinkles, they managed to pinpoint its exact location, and realised that the burst originated no more than 10,000 kilometres away from a rotating neutron star (which is very, very close in outer space terms). As a result, they say it’s likely that it was formed in the neutron star’s magnetosphere, a highly magnetic area that surrounds such ultracompact objects, which can fit the mass of our Sun into a space the size of a single city.

This isn’t great news for alien lovers, given the origins of FRBs were already so hotly contested. But there’s still something to get excited about, says Kiyoshi Masui, associate professor of physics at MIT, who worked on the paper. “Around these highly magnetic neutron stars, also known as magnetars, atoms can’t exist – they would just get torn apart by the magnetic fields,” says Masui. “The exciting thing here is, we find that the energy stored in those magnetic fields, close to the source, is twisting and reconfiguring such that it can be released as radio waves that we can see halfway across the universe.”

What does it all mean? Well, it means scientists are bumping up against “the limits of what the universe can produce,” explains lead author Kenzie Nimmo, of MIT’s Kavli Institute for Astrophysics and Space Research. It also gets us closer to understanding some of the fundamental physics at the heart of our universe. She adds: “There’s been a lot of debate about whether this bright radio emission could even escape from that extreme plasma.”

Presumably, scientists who have devoted their lives to finding evidence of extraterrestrial intelligence will be less pleased with the study’s results. For a long time, the mystery of FRBs has served as a vehicle for various theories, including alien military exercises or “light sails” – spacecraft used to haul cargo at close to the speed of light. For now, we’ll just have to make do with plain old stellar fireworks.