The interstellar visitor known as 3I/ATLAS has taken a surprising turn in its journey through the Solar System. New images captured after its close pass by the Sun show no cometary tail, a feature scientists expected to see if the object were behaving like a typical comet. The finding has intensified scientific debate surrounding the true nature of the massive, Manhattan-sized traveller and has raised questions about how objects from other star systems form, evolve, and behave.The object, first detected entering the Solar System in June, was predicted to shed dust and gas when heated by the Sun, producing a tail that would be pushed outward by solar radiation. This would have explained the unexpected acceleration observed in its motion last week. However, recent photographs taken at the R. Naves Observatory in Spain revealed no visible stream of gas or debris, even though the object passed close enough to the Sun for substantial heating.Harvard astrophysicist Avi Loeb noted that, based on expected models, around 13 percent of the object’s material should now be visibly dispersed. Instead, the object remains a compact point of light, with no clear signs of shedding or break-up. He said the absence of a tail challenges the assumption that 3I/ATLAS is a normal comet, suggesting instead that the object might be something non-natural or artificial.
What scientists expected from interstellar object 3I/ATLAS
For comets, heating from the Sun typically produces a bright halo of gas, known as a coma, and a long trailing tail. These features are driven by sublimation, where volatile ice changes directly into gas. The absence of these signatures in 3I/ATLAS challenges the assumption that it is a conventional comet.If 3I/ATLAS behaves like a natural comet, researchers say the coming weeks should reveal a noticeable cloud of gas as the viewing angle improves. As the object moves farther away from the Sun and into clearer viewing positions, astronomers will have more opportunities to test this expectation.
Why the discovery matters
3I/ATLAS is only the third confirmed interstellar object to enter our Solar System, following 1I/ʻOumuamua in 2017 and 2I/Borisov in 2019. Its behaviour therefore offers a rare opportunity to learn about objects formed around other stars. While Borisov behaved like a standard comet, ʻOumuamua also sparked scientific debate due to its unusual acceleration and lack of a visible tail.The parallels have not gone unnoticed.Avi Loeb has suggested that the unusual motion and lack of visible outgassing could indicate a non-natural origin. He argues that, if the object continues to show no tail despite ample solar heating, it may represent a new class of interstellar object, or possibly something manufactured rather than formed by natural processes. Other astronomers, however, urge caution and stress that atmospheric angles, dust composition, and observation timing must be carefully analysed before drawing such conclusions.
The next phase of observation
3I/ATLAS is now on its outbound path toward Jupiter, where it will pass closely on 16 March 2026. Both NASA and the European Space Agency are planning observations during this phase, which could offer the most detailed insights yet.Researchers are also awaiting high-resolution images taken by NASA’s Mars Orbiter HiRISE camera, although the release of those images has been delayed due to the ongoing government shutdown in the US.For now, the scientific community is in a state of cautious anticipation.3I/ATLAS may still behave like a comet.Or it may continue to break the rules.Either outcome promises to expand our understanding of what travels between the stars.
