Why 3I/ATLAS' Sunward Jet Holds Clues to Its True Nature

Interstellar object 3I/ATLAS Interstellar object 3I/ATLAS has been a topic in the news of astronomers around the world since it was accidentally discovered in July 2025 by the ATLAS telescope in Chile.

The object, which is estimated at 20-40 kilometres, is moving on a hyperbolic orbit at over 50 kilometres per second to confirm its extrasolar system origin.

This is also the third known interstellar probing of 3I/ATLAS, following 1I/'Oumuamua in 2017 and 2I/Borisov in 2019. However, unlike its predecessors, 3I/ATLAS is showing a phenomenon that has baffled scientists: a jet pointing towards the sun.

The Mystery Of The Sunward Jet

Typical comets have tails, which are emitted away from the Sun by the solar radiation and the solar wind. By contrast, 3I/ATLAS observations indicate a small jet pointing towards the Sun, with its nucleus about 6,000 kilometres away.

Harvard astrophysicist Avi Loeb has questioned this behaviour, arguing that it is inconsistent with standard cometary physics. Loeb examined the data and, in the analysis, observed that, assuming 3I/ATLAS were a typical comet, the comet's antitail jet could not have streaming gas beyond 5,000 kilometres.

Scientific Discussion And Hypothesis

The occurrence of a jet towards the sun has been a subject of controversy in the scientific community. Other scientists point to the possibility of the anomaly being caused by unusual outgassing patterns, perhaps due to the object's composition. Some people claim that the orientation and magnitude of the jet can refer to the new processes in interstellar comets that have been hitherto unobservable.

Loeb has reported eight anomalies in the 3I/ATLAS, including the jet, its trajectory, and spectral signatures. Although he has raised the hypothetical possibilities, mainstream astronomers point out that it is necessary to be careful and wait for more data before concluding.

Observational Evidence

The jet was visible in images taken by the Two-Meter Twin Telescope in August 2025 in the Canary Islands. A combination of 159 images revealed the purple jet stretching towards the sun, and the yellow line was a sign of where a normal comet tail was supposed to be.

More information from the ESA XMM-Newton spacecraft revealed the emission of low-energy X-rays when gases flowing out of 3I/ATLAS interact with the solar wind. These observations strengthen the view that the object is actively outgassing, but in a manner not fully understood by current models.

Implications For Astronomy

The anomalies reported by 3I/ATLAS highlight the challenges of researching interstellar objects. Every visitor provides an infrequent opportunity to test hypotheses about the formation of planetary systems and the behaviour of bodies in icy outer space.

The sunward jet, specifically, raises questions about the constitution and internal structure of 3I/ATLAS. Provided that the jet is propelled by other substances that are not typical of the solar system comets, it may give information about the diversity of the interstellar matter. Alternatively, when the jet's direction is affected by rotational processes or other forces, it can further our understanding of the physics of comets.

A Neutral Perspective

Although there have been speculations as to a non-natural origin, the mainstream scientific approach is sceptical. Astronomers emphasise that abnormal behaviour does not always denote extraordinary explanations. Instead, the emphasis is on collecting more data, since 3I/ATLAS is moving closer to perihelion and farther from the solar system.

According to Loeb himself, since 3I/ATLAS is a comet, the jet and anti-tail should not contain streaming gas beyond 5,000 kilometres. This remark underscores the importance of comparing old models with new evidence rather than rushing to conclude.

The example of 3I/ATLAS indicates that interstellar visitors can disrupt existing astronomical structures. Its jet towards the sun is an apparent oddity that can help clarify its true nature, either as a comet with peculiar characteristics or as a representative of a larger group of interstellar objects that have not yet been fully understood.

At least at present, the scientific community is still witnessing and studying, understanding that every single interstellar landing is an opportunity to improve our understanding of the universe.