When it comes to the existence of intelligent life beyond Earth, there’s a big question that remains unanswered: why haven’t we seen any evidence yet? Now, though, a group of scientists are attempting to do just that, with the launch of a groundbreaking, galaxy-spanning search for giant extraterrestrial civilisations.

Researchers from the SETI Institute (Search for Extraterrestrial Intelligence) recently announced the first-ever extragalactic search for alien technosignatures, in collaboration with Berkeley SETI Research Center and the International Centre for Radio Astronomy Research. What that means is that they’re hunting for evidence of alien technologies in galaxies beyond the Milky Way. The idea? That tech like city lights, giant megastructures, and satellites will be much easier to spot than the creatures that created them.

It’s not the first time astronomers have used their telescopes to search for technosignatures in the night sky, but it is the first meaningful search beyond our home galaxy. The innovative study involves looking at wide swathes of space, using a group of telescopes called the Murchison Widefield Array (MWA) to survey around 2,800 galaxies in a single observation, with a focus on low radio frequencies.

The study isn’t just significant because of its size. If it was, in fact, to pick up signs of alien life beyond our galaxy, the signal would need to have been transmitted by beings with technology powerful enough to harness energy from their home star, or even several stars in their galaxy. In other words, they’d be at least a Type II on the Kardashev Scale (we’re not even a Type I yet) and therefore qualify as a “super civilisation”. This study is one of the deepest and most detailed searches for super civilisations to date.

“This work represents a significant step forward in our efforts to detect signals from advanced extraterrestrial civilisations,” says the SETI Institute’s Dr Chenoa Tremblay, who leads the study alongside Prof Steven Tingay of Curtin University. “The large field of view and low-frequency range of the MWA makes it an ideal tool for this kind of research, and the limits we set will guide future studies.”

Tingay, who is also the director of the MWA, adds that the telescope array – which comprises 4,096 spider-like antennae – opens up new ways of hunting for intelligent life in the universe, using the same data used to understand the astrophysics of stars and galaxies. “This work is new and novel,” he says, “but also paves the way for future observations with even more powerful telescopes.”

What have the researchers found so far? Not much, unfortunately. But that doesn’t mean super-civilisations aren’t out there. If and when we stumble across one, we’ll be faced with a whole new set of space exploration questions. For one: is it worth taking the risk of getting in touch with a civilisation far more powerful than our own?