Astrophysicist Avi Loeb from Harvard University has sparked intrigue regarding the interstellar comet known as 3I/ATLAS. In a recent blog update, he suggested that the comet’s unusual behaviors, including its jets and an unusual ‘anti-tail,’ may indicate a non-natural origin. This speculation aligns with a growing debate in the scientific community about the comet’s characteristics as it traverses the Solar System.
Loeb pointed out that 3I/ATLAS exhibited unexpected traits, such as jets that have continued to emerge even after its perihelion passage—its closest approach to the Sun. He noted that images captured on November 11, 2025, show the comet as a single entity, with no visible signs of disintegration, which is atypical for comets during such close solar proximity. He stated, “Given that the large-scale jets reported recently, the fact that 3I/ATLAS remains a single body is surprising for a natural comet.”
The presence of these jets has led Loeb to propose that they could be indicative of technological thrusters from an extraterrestrial spacecraft. He elaborated, “Technological thrusters which point their exhaust towards the Sun would accelerate away from the Sun. This post-perihelion maneuver might be employed by a spacecraft that aims to gain speed rather than slow down through the gravitational assist from the Sun.” To quantify his observations, Loeb introduced the concept of a “Loeb Scale,” where he currently rates 3I/ATLAS at a 6, suggesting a significant possibility of it being an artificial object.
Contrastingly, Qicheng Zhang, a postdoctoral fellow at the Lowell Observatory, disagrees with Loeb’s assertions. He argues that 3I/ATLAS has not shown signs of breaking apart, stating, “All the images I’ve seen show a fairly ordinary/healthy looking comet. There’s no sign at all that the nucleus broke apart.” Zhang criticized Loeb’s interpretation, suggesting that it is based on flawed calculations of the comet’s orbit.
As 3I/ATLAS continues its journey, it is expected to make its closest approach to Earth on December 19, 2025. The renewed observations of the comet follow a period of invisibility due to its position behind the Sun in late October. The contrasting views of Loeb and Zhang highlight the ongoing fascination and debate surrounding the comet’s nature.
While Loeb’s theories regarding the potential for extraterrestrial life may capture public interest, Zhang’s stance emphasizes the need for scientific rigor and careful analysis in interpreting the behavior of celestial bodies. The upcoming close approach of 3I/ATLAS may provide further opportunities for observation and data collection, potentially clarifying the comet’s enigmatic characteristics.
