ITC Colloquium: Avi Loeb - Searching for Extraterrestrial Technological Artifacts Near Earth

In person for CfA members and available to watch on YouTube.

Searching for Extraterrestrial Technological Artifacts Near Earth

Over the past decade, the first interstellar objects were discovered. They include several interstellar meteors including IM1, detected on January 8, 2014, 1I/`Oumuamua detected on October 19, 2017, 2I/Borisov detected on August 29, 2019 and 3I/ATLAS detected on July 1, 2025. Among these, the second and fourth appeared anomalous relative to known solar-system rocks whereas the third appeared to be a familiar comet. IM1 exhibited the highest material strength among all meteorites in the CNEOS catalog of NASA. In June 2023 we recovered 850 spherules from the Pacific Ocean site IM1. A tenth of these submillimeter meteoritic spherules displayed a unique chemical composition, different from familiar solar system materials. 1I/`Oumuamua featured a flat shape and non-gravitational acceleration with no detectable cometary evaporation.  3I/ATLAS has chemical and geometric anomalies, including a trajectory aligned to within 5 degrees of the ecliptic plane. Currently, new Galileo Project Observatories are monitoring millions of objects near Earth in the infrared, optical, radio and audio and analyzing their nature with machine-learning software. Forthcoming data from the Rubin Observatory in Chile will offer additional clues on the nature of interstellar objects. Are products from extraterrestrial technological civilizations lurking among the natural interstellar rocks?