Avi Loeb

Avi Loeb is a professor of astrophysics at Harvard University, former chair of its astronomy department, and arguably the most prominent mainstream scientist to treat the search for alien technology near Earth as legitimate observational science. He founded the Galileo Project to do it with telescopes rather than testimony.

Loeb's conventional career spans hundreds of papers on black holes, the early universe, and the first stars, plus leadership of the Breakthrough Starshot initiative. His public turn began with the 2017 interstellar object 'Oumuamua.

Loeb argued in peer-reviewed and popular writing that 'Oumuamua's anomalies, its extreme shape and non-gravitational acceleration without visible outgassing, permitted an artificial-origin hypothesis, expanded in his bestseller Extraterrestrial (2021). He founded the Galileo Project that year to build instrumented observatories that survey the sky for anomalous objects with calibrated sensors, publishing methods papers and commissioning stations. His 2023 Pacific expedition recovered millimeter spherules from the seafloor near the 2014 IM1 meteor's path, publishing analyses of unusual composition; critics dispute both the meteor's interstellar classification and the spherules' provenance. He co-wrote a physical-constraints paper with AARO's Sean Kirkpatrick, and has commented throughout the 2025-2026 interstellar-object news cycles, including 3I/ATLAS.

Loeb's claim is a posture: artificial origin is a hypothesis to test, not a taboo. His contribution is instrumentation and publication, dragging the question into observational astronomy, plus a public-communication engine his critics consider its own phenomenon.

Many astronomers say he overclaims against consensus explanations (a nitrogen-ice or hydrogen-rich body for 'Oumuamua, ordinary ablation debris for the spherules) and that his media volume distorts science communication. Loeb answers that his critics prefer ridicule to data collection. The dispute is now a standing feature of the field.

Loeb continues at Harvard and the Galileo Project, publishing prolifically through the current interstellar-object era.