Imagine an alien civilization with advanced technologies like city-size starships or planet-wide mines. Over time, erosion in space wears down these infrastructures, releasing microscopic debris that could drift across the galaxy. If such civilizations collapsed, their remains might be even more widespread, potentially sprinkling particles across countless worlds—including the moon. A team of scientists from the SETI Institute proposes searching for these microscopic remnants in lunar soil to answer whether we are alone in the universe.

"If any other technological civilization has ever existed in our galaxy, it's not an unreasonable hypothesis to think that particles of them are on the moon in some quantity," said Lewis Pinault, an affiliate scientist at the SETI Institute in Mountain View, Calif., and researcher at Birkbeck College, University of London, who led the study.

The team modeled how alien infrastructure might erode into tiny particles and how they could travel through the galaxy, potentially intersecting with our solar system. Sofia Sheikh, a scientist at the SETI Institute, called the idea "a creative and worthwhile avenue," especially amid renewed lunar interest from NASA's Artemis program. Ian Crawford, a professor of planetary science at Birkbeck College, argued that searching for technological artifacts is as valid as listening for radio signals.

The concept draws inspiration from Ukrainian researcher Alexey V. Arkhipov, who in the 1990s suggested the moon could collect alien artifacts. The team revived this idea, focusing on micron-scale particles named "Arkhipov particles" in his honor.