Harvard Professor Avi Loeb Warns 3I/ATLAS Could Be a Rare 'Black Swan' or a Trojan Horse in Space

Harvard astrophysicist Professor Avi Loeb has issued a stark warning that the interstellar object 3I/ATLAS may not be the benign comet scientists initially claimed, but instead a rare 'Black Swan' or even a Trojan Horse with potential implications for Earth and humanity. For months, Loeb has pressed for a broader investigation into 3I/ATLAS's unusual behaviours and characteristics, challenging conventional interpretations.

He is urging observers not to dismiss the possibility that the object could be artificial, or at least far more complex than a standard icy comet. While most scientific interpretations say 3I/ATLAS exhibits typical cometary features, Loeb contends that several aspects of the object defy simple categorisation and deserve closer attention before being casually dismissed.

Unlikely Visitor From Beyond

3I/ATLAS was first detected on 1 July 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Chile as it entered the Solar System from interstellar space. Its hyperbolic trajectory confirmed it was not bound to the Sun, making it only the third such object ever observed, after 1I/ʻOumuamua and 2I/Borisov.

In most scientific interpretations, 3I/ATLAS exhibits typical cometary features, including the outgassing of water and carbon dioxide. These volatile signatures are consistent with the known physics of comets.

But Loeb contends that several aspects of the object defy simple comet categorisation and deserve closer attention before being fully understood or casually dismissed.

A 'Black Swan' with Suspicious Anomalies

In recent months, Loeb has used scientific writings and media appearances to describe 3I/ATLAS as a potential 'Black Swan' event. He interpreted the CIA's response to a Freedom of Information Act request—which said it could neither confirm nor deny the existence of records on the object—as indicative that intelligence agencies might be assessing unexpected risks privately.

Loeb wrote that the CIA's ambiguous reply suggests some officials may view the discovery through the lens of low-probability, high-impact risks, the very definition of a Black Swan occurrence. This, he insists, deserves serious scientific and policy attention.

He has also repeatedly emphasised that anomalies in the data, such as unusual jet structures, the object's mass and composition, and its orbital alignment, are not yet fully explained by standard comet models.

Challenging the Standard View

NASA and mainstream astronomers maintain that 3I/ATLAS's behaviour falls within expectations for a cometary body. High-resolution images show a diffuse coma and gas emissions consistent with the sublimation of volatile ices.

Loeb, however, has characterised the released imagery as insufficient to rule out anomalies. In public statements and a lengthy Q&A transcript posted on his Medium blog, he criticised the communication strategy of space agencies for downplaying the mysteries associated with 3I/ATLAS.

In that transcript, Loeb argued that the elongated structure around the object and the orientation of observed material relative to the Sun do not match expectations for typical comet outgassing patterns.

The 'Trojan Horse' Analogy

Perhaps most striking has been Loeb's use of the Trojan Horse analogy. He suggests that an object arriving from interstellar space and assumed to be benign might conceal non-obvious complexities or structures, much as the ancient wooden horse concealed soldiers. While Loeb explicitly acknowledges that such scenarios are speculative, he insists that science should not close off investigation simply because the most ordinary explanation is easier.

Loeb's call for vigilance extends to large-scale observation campaigns. He has advocated for continued scrutiny of 3I/ATLAS as it passes near Jupiter in early 2026, where new data might either confirm or dispel his speculations. He has also referenced his proposed 'Loeb Classification Scale' for the threat level of interstellar objects, suggesting that even a 30–40 per cent chance of non-natural origin, as he has informally estimated, merits careful scientific consideration.

Scientific Community Remains Cautious

The scientific community remains sceptical. Many planetary scientists argue that the evidence overwhelmingly supports a natural origin for 3I/ATLAS, with observations of water vapour and carbon dioxide being typical of cometary behaviour.

Critics also highlight that some of the claimed anomalies might stem from limited data quality or incomplete observations, rather than novel physics or engineering. Sceptics argue that extraordinary claims require extraordinary evidence, a standard that Loeb's hypotheses have yet to meet.

Still, Loeb's stance has driven renewed debate not only about 3I/ATLAS but about how scientists handle outliers and rare events in astronomy. The coming months of observation, particularly as the object interacts with Jupiter's gravitational field, may provide crucial data that will either reinforce the mainstream view or deepen the mystery.