The hunt for alien tech

Can scientists tune in to Radio Alien? Govert Schilling investigates the cosmic clues that might reveal intelligent life through its technology

- Govert Schilling

When comet 3I/ATLAS was discovered in July, on a one-way interstellar journey through our Solar System, Harvard astronomer Avi Loeb suggested it might be an alien spacecraft paying us a visit. Back in 2017, he made similar claims about the very first known interstellar object, the asteroid 1I/'Oumuamua. In fact, despite their somewhat unusual properties, both celestial bodies appear to be completely natural, and most astronomers dismiss Loeb's speculative assertions.

But what if he was right? What if we really did find a piece of alien hardware?

"Proof of the existence of extraterrestrial intelligence would be the most important discovery in human history," says Andrew Siemion, principal investigator at the privately funded Breakthrough Listen programme.

And while Breakthrough Listen uses radio telescopes around the world to search for possible interstellar broadcasts – an approach known as SETI (Search for Extra-Terrestrial Intelligence) – astronomers are now thinking seriously about how to broaden the search by looking for ‘technosignatures’, other telltale traces of alien technology. Spaceships, for instance.

The idea isn't new. In his 1973 science-fiction novel Rendezvous with Rama, Arthur C Clarke described the discovery and subsequent exploration of a huge alien craft that happened to pass through our Solar System. Five years earlier, in 2001: A Space Odyssey, Clarke and director Stanley Kubrick imagined how mysterious beings left huge monoliths behind in the Solar System to guide the slow progress of human evolution.

What alien tech might look like