The recent discovery of the third known interstellar object (ISO), 3I/ATLAS, has brought about another round of debate on whether these objects could potentially be technological in origin. Everything from random YouTube channels to tenured Harvard professors have thoughts about whether ISOs might actually be spaceships, but the general consensus of the scientific community is that they aren’t. Overturning that consensus would require a lot of “extraordinary evidence”, and a new paper led by James Davenport at the DiRAC Institute at the University of Washington lays out some of the ways that astronomers could collect that evidence for either the current ISO or any new ones we might find.

That evidence, known in the search for extraterrestrial intelligence (SETI) circles as “technosignatures”, implies that a technological civilization crafted the objects making their way through our solar system. Technosignature searches don’t just happen for ISOs though - there are branches of SETI that look at everything from Dyson swarms around other stars to trying to find a hidden Monolith like that from 2001: A Space Odyssey somewhere on a moon in our solar system.

Since ISOs are still a relatively new discovery, despite their theorized existence for years, they are at the forefront of technosignature research. And the paper posits four different types of technosignatures astronomers might be able to find on one of them.