Harvard astrophysicist Avi Loeb has raised questions about the interstellar comet known as 3I/ATLAS, suggesting that its behavior might not be entirely natural. His observations, made public on his blog, center around peculiar features of the comet, including the presence of jets and what he describes as an ‘anti-tail.’ These characteristics have sparked speculation about the possibility of extraterrestrial technology involved.
Loeb noted that 3I/ATLAS has not exhibited the expected breakup after its close approach to the Sun, which is typically observed with comets. He stated, “Images taken of 3I/ATLAS on November 11, 2025, show a single body, with no evidence for breakup following the perihelion passage two weeks earlier.” This observation has led him to consider that the jets emanating from the comet could be indicative of a spacecraft rather than a natural phenomenon.
Unusual Characteristics Raise Eyebrows
One of the more intriguing aspects of 3I/ATLAS is its jets, which continue to emit material even after the comet’s perihelion, or closest approach to the Sun. Loeb posited that “technological thrusters which point their exhaust towards the Sun would accelerate away from the Sun.” This mechanism could potentially explain the observed behavior if the comet were indeed a spacecraft aimed at maximizing its speed.
To assess the nature of interstellar objects, Loeb proposed a “Loeb Scale,” where “0” represents a confirmed natural object and “10” indicates a clearly technological one. He currently rates 3I/ATLAS at a 6 on this scale, suggesting that further observations might clarify its nature as it approaches Earth.
The comet is set to make its closest approach to our planet on December 19, 2025, which has heightened interest among astronomers and the public alike.
Contrasting Opinions from Astronomers
Despite Loeb’s assertions, other astronomers are skeptical of his conclusions. Qicheng Zhang, a postdoctoral fellow at the Lowell Observatory, expressed doubt regarding the notion that 3I/ATLAS could be anything other than a typical comet. Zhang stated, “All the images I’ve seen show a fairly ordinary/healthy looking comet. There’s no sign at all that the nucleus broke apart.” He criticized Loeb’s interpretation, suggesting it is based on a miscalculation of the comet’s orbital parameters.
As 3I/ATLAS re-emerges from behind the Sun, astronomers are eager to gather more data. Loeb’s hypothesis, while controversial, has reignited the discussion about the nature of interstellar objects and the potential for extraterrestrial life. The anticipation surrounding the upcoming close approach may provide the necessary observations to either support or refute these claims.
As the scientific community continues to analyze the data, the debate surrounding 3I/ATLAS is set to deepen, emphasizing the fine line between scientific inquiry and speculation in the field of astrophysics.
