Harvard astrophysicist Avi Loeb weighed in on the new observations of mysterious interstellar object 3I/ATLAS gathered by the Nordic Optical Telescope in Spain’s Canary Islands. New findings showed that comet’s unusual anti-solar tail has changed direction, facing away from the Sun.
The mysterious space object with a tail sparked speculation about its possible origin, with the scientist suggesting in his recent paper that this tail could be indicative of a “controlled manoeuvring” alien craft and a high-impact Black Swan event.
3I/ATLAS, believed to have originated from outside our solar system, was first detected in July 2025 by the ATLAS survey telescope. The Nordic Optical Telescope in Spain’s Canary Islands captured its new images in September.
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Previous observations during July and August 2025 confirmed that the space object has a rare “anti-solar tail”. But the new images reveal that the anti-tail turned into a tail in September 2025.
The comet exhibits unusual behaviour, including a gas jet pointed towards the Sun, a lack of a typical cometary tail and emission of nickel tetracarbonyl, which is a compound previously unknown in natural comets.
“My colleague, Adam Hibberd, pointed out that if the object is an alien spacecraft slowing down, and the anti-tail is braking thrust, then this change from anti-tail to tail would be entirely expected near perihelion,” says Loeb.
“In that case, the transition would constitute a technosignature in the form of an unexpected phenomenon indicative of controlled maneuvering, possibly with the intention of achieving a bound heliocentric orbit between Mars’s and Jupiter’s orbits.”
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The comet was supposed to reach its closest point to the Sun on October 29, 2025, at about 1.36 astronomical units (AU) from the Sun. Recent images show materials being removed behind as it travels toward the Sun, and hit by up to 33 gigawatts of solar radiation.
This has led Loeb to speculate about the possibility of a “manoeuvring” alien craft. But the international space agencies have not confirmed such speculations, with NASA earlier saying that the object is expected to make its closest approach to Earth at a safe distance, posing no threat.
Loeb’s speculations have gained attention, but many scientists remain sceptical, suggesting that the object has comet-like properties and behaviour.
Meanwhile, the International Asteroid Warning Network has added 3I/ATLAS to its list of targets for scientific observation, and astronomers are eagerly awaiting further insights into this enigmatic object.
“While it poses no threat, comet 3I/ATLAS present a great opportunity for the IAWN community to perform an observing exercise due to its prolonged observability from Earth and its high interest to the scientific community,” the group wrote on its website.