Researchers from Harvard University, led by astrophysicist Avi Loeb, have published a study suggesting that the interstellar object known as 3I/ATLAS, detected in July 2025, may not be a naturally occurring celestial body. This investigation, conducted in collaboration with scientists from London, explores the notion that 3I/ATLAS could be a technological artifact from an extraterrestrial civilization, based on unusual anomalies noted in its trajectory.
The timing of this analysis coincides with the object”s perihelion, which is projected to occur on October 29, 2025, when 3I/ATLAS will be at a distance of 203 million kilometers from the Sun. The impetus for this research stems from a desire to explore hypotheses regarding cosmic signals, aiming to address the Fermi paradox, which questions why we have not yet encountered evidence of extraterrestrial life.
3I/ATLAS is the third confirmed interstellar object, following “Oumuamua and Borisov, and it travels at a speed of 60 kilometers per second. Its characteristics challenge standard models of asteroids and comets, leading the authors to suggest a potential engineered origin. They highlight that the object”s orbital path exhibits precise alignments with various planets in our Solar System, a scenario Loeb describes as an improbable coincidence.
In September 2025, 3I/ATLAS will pass near Venus, followed by Mars in October and Jupiter in December, with an estimated probability of only 0.005%. This alignment could imply an optimized trajectory, reminiscent of human space missions. The study references the “dark forest hypothesis,” a concept from science fiction that interprets the silence of the cosmos as a survival tactic, where advanced civilizations refrain from making detectable emissions to evade potential threats.
Loeb likens the investigation to “Pascal”s wager,” arguing that ignoring existential risks is less sensible than actively exploring them. The paper, which was initially posted on arXiv in July 2025 and updated in October, employs interplanetary trajectory software to simulate different scenarios. Observations from the Hubble Space Telescope in July 2025 revealed a diffuse glow surrounding 3I/ATLAS, initially thought to be an anti-tail, but which transformed into a typical tail by September.
Photographs taken by the European Space Agency on October 7 show a bright coma near Mars, with estimates indicating a mass loss of around 2 million tons by October. However, the object”s unique composition, rich in nickel but poor in iron, poses challenges to conventional models for natural interstellar comets. At the time of perihelion, the surface will be subjected to 33 gigawatts of solar radiation, possibly triggering reactions that could distinguish between natural and artificial objects.
The authors propose that if a non-gravitational acceleration were to divert 3I/ATLAS into a trajectory heading towards the Sun, it would allow for extended observation. This maneuver, referred to as reverse Oberth, optimizes propulsion in strong gravitational fields and could be feasible for interstellar spacecraft. Loeb assesses the likelihood of 3I/ATLAS having a non-natural origin at 30-40%, based on eight anomalies identified since its discovery on July 1, 2025, by the ATLAS system in Chile.
This object is believed to originate from the thick disk of the Milky Way and aligns with the direction of the famous “Wow!” signal detected in 1977, with a probability of occurrence at 0.6%. While NASA has confirmed that there is no threat to Earth, they continue to monitor the object through the Center for Near-Earth Object Studies.
The upcoming Vera C. Rubin Observatory, expected to be fully operational in 2026, aims to enhance the detection of interstellar objects by up to one hundred annually, aiding in the search for technosignals. Proposed initiatives include rapid intercept missions to collect samples, drawing inspiration from the lessons learned from “Oumuamua. Loeb advocates for observations post-perihelion, particularly during the object”s close approach to Earth on December 19, 2025, to facilitate detailed spectroscopic analyses.
These efforts are directed at classifying 3I/ATLAS on what Loeb terms the “Loeb scale,” which ranks anomalies from 1 to 10, with the object currently positioned at level 4. The study underscores the urgent need for protocols regarding interstellar visitors, encouraging collaboration among NASA, the European Space Agency, and independent research institutions.
