The interstellar object 3I/ATLAS has once again defied expectations. After the Hubble Space Telescope captured its unusual “anti-tail” earlier this year, the object has now reversed its orientation — its tail now points away from the Sun.
According to Harvard astrophysicist Avi Loeb, this shift could be more than just a natural phenomenon — it might even hint at “a technological maneuver.”
From Anti-Tail to Classic Tail
Observations from the Nordic Optical Telescope confirmed that the anti-tail seen over the summer disappeared by September, replaced by a standard cometary tail. Scientists attribute this to the varying reactions of dust and ice particles on the comet’s surface to sunlight.
As 3I/ATLAS approached the Sun, rising temperatures caused frozen carbon dioxide and water ice to sublimate, reversing the tail’s direction.
Material Loss and Speculation
Researchers estimate the comet is losing around 150 kilograms of mass per second, mostly carbon dioxide and carbon monoxide. Between July and October 2025, this totaled roughly two million tons — equivalent to just a few centimeters shaved off its outer layer.
Loeb and his colleague Eric Keto developed a model explaining the behavior, but some of their team members suggest that if 3I/ATLAS were an artificial craft, this reversal might represent a deliberate deceleration maneuver.
Divided Opinions
NASA and most astronomers maintain that 3I/ATLAS is a natural comet, but its anti-tail, color anomalies, and gas emissions keep the debate alive. As the object nears its closest approach to the Sun in December 2025, scientists hope the increased solar exposure will reveal clues about its true nature.