Avi Loeb, a renowned Israeli‑American astrophysicist and Harvard professor, has become one of the most provocative voices in the search for extraterrestrial life. Director of the Institute for Theory and Computation at Harvard since 2007, Loeb has authored over a thousand scientific papers and multiple bestselling books, including Extraterrestrial and Interstellar. He has consistently challenged mainstream astronomy, suggesting that some interstellar objects entering our solar system might not be natural. Loeb recently sparked global attention by proposing that 3I/ATLAS, an interstellar object discovered in July 2025, could, at least hypothetically, be a technological artifact from an alien civilization, rather than a conventional comet.
Avi Loeb’s claim: Could 3I/ATLAS be alien technology
When 3I/ATLAS was first observed by the Asteroid Terrestrial-impact Last Alert System (ATLAS), Loeb and colleagues immediately noted several unusual features. Its hyperbolic orbit indicates it originated outside our solar system, yet its trajectory aligns unusually well with the planetary orbital plane. The object is massive, possibly tens of kilometers across, and emits water vapor far from the Sun, behavior atypical for comets. It also lacks a typical cometary dust tail, prompting Loeb to speculate whether some of its glow could arise from artificial rather than natural processes. Loeb frames this as a low-probability, “black swan” scenario, encouraging observational follow-ups to explore the hypothesis.
Who is Avi Loeb? His work and achievements
Avi Loeb (Abraham Loeb) is the Frank B. Baird Jr. Professor of Science at Harvard University and has served as Chair of Harvard’s Department of Astronomy from 2011 to 2020. He is the founding director of Harvard’s Black Hole Initiative and leads the Galileo Project, aimed at systematically searching for evidence of extraterrestrial technological signatures. Loeb has worked extensively on black holes, the first stars, the early universe, and interstellar objects. He has published over a thousand scientific papers and several bestselling books, often blending cutting-edge physics with bold, provocative ideas about life beyond Earth.
Mainstream scientific views about 3I/ATLAS
Most astronomers and agencies, including NASA and ESA, have rejected the notion that 3I/ATLAS is alien. Observations indicate its chemical composition, including water ice and carbon dioxide, is consistent with naturally formed interstellar comets. Its hyperbolic trajectory confirms its extrasolar origin, but nothing in its observed behavior necessitates an artificial explanation. SETI and other research institutions have noted that Loeb’s suggestion is largely pedagogical, it is a theoretical exploration rather than a confirmed finding. Scientists emphasize that while entertaining, the alien spacecraft hypothesis is far less probable than conventional cometary origins.
Recent discovery: Water emission far from the Sun
One of the most intriguing findings about 3I/ATLAS is its unexpected water activity. Detected using NASA’s Swift Observatory, the object emits around 40 kilograms of water per second from at least 8% of its surface, much further from the Sun than standard cometary sublimation would. allowed. This anomalous behavior challenges models of interstellar comet activity, offering new insights into how icy bodies evolve in the cold depths of space. Multiple observatories, including Mars orbiters, have confirmed this water emission, making 3I/ATLAS a unique subject for studying the distribution of water and organic compounds in extrasolar. systems.
Context of discovery and ATLAS project
3I/ATLAS was discovered on 1 July 2025 by ATLAS, roughly 675 million kilometers from the Sun. It is the third confirmed interstellar object to enter our solar system, after ‘Oumuamua in 2017 and Borisov in 2019. Scientists continue to study its trajectory, composition, and activity to better understand. interstellar objects and their origins. Despite its extraordinary features, 3I/ATLAS poses no threat to Earth, never approaching closer than 1.8 astronomical units. Its study offers unprecedented opportunities to learn about extrasolar planetary systems and the chemistry of distant protoplanetary discs.
