Earlier this month, Canadian researchers announced they’d discovered a powerful radio signal, emanating from a distant galaxy in bursts every 16 days.

And Avi Loeb, the chair of Harvard University’s astronomy department, told Futurism this week that he thinks one possibility is that the signals are coming from an alien civilization.

To be clear, Loeb also acknowledged that the signals — “fast radio bursts,” or FRBs — could be generated by young neutron stars called magnetars, or by another, yet-undiscovered natural phenomenon.

“But at the moment we do not have a smoking gun that clearly indicates the nature of FRBs,” he wrote in an email. “So all possibilities should be considered, including an artificial origin.”

One concrete possibility, he said, is an extraterrestrial civilization using a beam of energy to propel cargo through space — and that the Canadian researchers picking up radiation leaking away from it.

Loeb pointed out that he previously examined that concept in a 2017 paper, however, and found that the energy required to move cargo with energy beams would be absolutely staggering. In fact, he said, such a beam would require about as much energy as the entirety of sunlight that hits the Earth.

“This would require a huge engineering project, far more ambitious than we currently have on Earth,” he wrote. “So the main technological challenge is in the huge power that the radio beam need[s] to carry.”

The Canadian researchers themselves acknowledged, in a followup press release about the findings, that “non-professionals have suggested they are messages from aliens.”

Loeb, though, thinks the possibility is worth seriously considering — in addition, of course, to natural causes. He also pointed out that different FRBs could conceivably be caused by different phenomena.

This isn’t the first SETI story Loeb has waded into. In 2018, for instance, he suggested that the interstellar object ‘Oumuama might be an alien probe.

“An advanced technological civilization is a good approximation to God,” he told the New Yorker at the time. “Suppose you took a cell phone and showed it to a caveperson. The caveperson would say it was a nice rock. The caveperson is used to rocks. So now imagine this object — ‘Oumuamua— being the iPhone and us being the cave people.”