Scientists have observed fast radio bursts coming from somewhere deep in space, in what is only the second time repeated blasts of signals like this have been recorded, according to a study published in the journal Nature.

The finding was presented in Seattle earlier this month at the 233rd meeting of the American Astronomical Society.

The recent observation is sure to deepen the mystery of deep space but may also offer an opportunity to actually understand the signals and where they may be coming from. Speculation on the origins of the signals range anywhere from exploding stars to communication from extraterrestrial civilizations.

The bursts, which last a mere milisecond and are thrust into space using the same amount of energy the sun takes 12 months to produce, are mysterious but not exactly unusual. The unusual thing is that at least one signal in the newest batch was observed repeating six times and came from the exact some location, 1.5 billion light-years away, each time.

This is only the second time a signal has been observed repeating.

Until now, there was only one known repeating FRB. Knowing that there is another suggests that there could be more out there. And with more repeaters and more sources available for study, we may be able to understand these cosmic puzzles—where they’re from and what causes them,” said Ingrid Stairs, member of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) team and an astrophysicist at the University of British Columbia.

The new radio telescope used wasn’t even operating at full capacity during the summer of 2018 when it detected the radio signals. The fact that humans have observed two instances of repeating signals means there is a strong likelihood that a “substantial population” of repeating signals exists in space, the researchers noted in Nature.

Having observed and recorded two sets of repeating bursts may help scientists better understand what makes them different from single bursts. While recording these bursts doesn’t shine any more light on what they are or where they come from, their recent observation may help scientists know where and how to look for repeating signals in the future.

According to CNN:

One hypothesis is that powerful astrophysical phenomena are causing them. The first repeating fast radio burst was recorded at a frequency of 700 megahertz, but some of the bursts CHIME recorded were as low as 400 megahertz.

Whatever the source of these radio waves is, it’s interesting to see how wide a range of frequencies it can produce,” said team member Arun Naidu.

Researchers are confident that the CHIME telescope, once no longer operating in its pre-commissioning phase, will soon find additional repeating fast radio bursts, potentially adding more to both the mystery and understanding of deep space.