Seeking aliens? Watch out for tech more than biosignatures

Aliens have still eluded us no matter where we look. Are we really alone in the universe, or could it be we haven’t been searching for the right signs of an intelligent species beyond Earth?

Maybe we need to shift our focus from biosignatures to technosignatures. Whatever extraterrestrial technology is like, it’s probably much more advanced than the “radio” Resident Alien's Harry Vanderspiegle comes up with to transmit signals to his home planet, though he only hears from a random pizza place. Any civilization that has survived that long without self-destructing can probably do better than a hodgepodge of office equipment set up on a tripod.

The thing is that biosignatures can be ambiguous. What look like fossils from another world can turn out to have been formed by chemical processes, and organic substances on or around a body in space don’t necessarily mean something is actually living there. Maybe the biological signatures of alien life-forms are not even remotely close to life as we know it. Researcher Jason Wright of Penn State University, who led a study recently published in The Astrophysical Journal Letters, thinks that we have a better chance of finding aliens through technosignatures.

“Communicative signals are the most unambiguous,” he told SYFY WIRE. “If we saw a narrowband radio or laser transmission, there's just no way it could be natural. Then, the only ambiguity is if it has somehow come from our own technology.”

It took 4 billion years after life emerged on Earth for an intelligent species to evolve. We are the only one we know of in the universe — for now. That makes it seem like alien hunters would be much more likely to find biological signs of life, which may still be eons away from morphing into anything intelligent, but then the ambiguity of biosignatures gets in the way again. It is already obvious that organics can be deceiving. Earthlings also aren’t going to recognize the biology of life as we never knew it.

Enter the Drake equation. Spawned by the ongoing search for extraterrestrial radio signals, it is supposed to give us an idea of how many detectable alien societies, at least those able to transmit messages, could be out there. This remains an unsolvable equation and runs into some issues when it sometimes ends up favoring biosignatures over technosignatures. The way it is set up suggests that we are more likely to find biosignatures, even if the life that gives them off is not intelligent.

But wait. Technosignatures don’t have to stay grounded. They can be found far from any planet or moon or floating space habitat, just like the Voyagers. Alien technology could also potentially self-replicate. It doesn’t have to be in probe form like a von Neumann probe. Hypothetically, if there were aliens exploiting the resources of the asteroid belt, they could mine just about every viable asteroid with self-replicating technology that would keep multiplying over and over again.

“A set of machines can mine things like asteroids for materials, with another set refining those raw materials into the components of the machines, and another set crafting a new set of machines, with a final set bringing those machines to a new asteroid,” said Wright.

By updating the Drake equation, which first came into being when physically and observationally searching for biosignatures was next to impossible, Wright and his team were able to show that the search for technosignatures is worth putting more effort into. Technology can outlive its creators, even destroy the biosphere they came from, but would still be detectable. If the human civilization on Earth were to be extinguished by an astroid right now, the Voyager probes that have made it to interstellar space would still be beaming signals that are definitely artificial.

You also have to consider a civilization that managed to survive much longer than we have without collapsing in on itself. Such aliens would probably want to start expanding their presence in the cosmos, taking their gadgets along for the ride, which could actually result in more technospheres than biospheres. It isn’t that far off from the off-Earth cities that space tech moguls like Elon Musk and Jeff Bezos want to build. Humans are just in the conception phase, while (hypothetical) aliens that have millions of years on us might be spreading out.

So how detectable could alien technosignatures be if you factor out the noise? There is one thing they do have in common with biosignatures here. We can go off what we already know from Earth, but we don’t know exactly what extraterrestrial technology would manifest as.

"Technosignatures will probably be very challenging to detect, and since they represent products of alien forms of life, we aren't exactly sure what we are looking for,” Wright said. “This means when we find one, it may be ambiguous.”

Still, the James Webb Telescope can see further than any space telescope before it, and upcoming ground and space telescopes may be able to pick up something if someone is phoning home.

Resident Alien's first season, as well as the first half of Season 2, is streaming now on Peacock. New episodes return this summer on SYFY.