The anomalous behavior of a comet continues to fascinate

Discovered on July 1, 2025, this comet does not follow a classical orbit around the Sun, but a so-called hyperbolic trajectory, suggesting that it could originate from beyond our solar system.

3I/ATLAS, an interstellar comet, has recently attracted the attention of many scientists due to its unusual trajectory.

Described as an interstellar visitor, it is now at the center of scientific debate. Every one of its movements is being closely observed, including its recent non-gravitational acceleration.

What makes 3I/ATLAS particularly enigmatic is its atypical orbital behavior.

Indeed, its trajectory reveals an acceleration that exceeds what gravitational attraction alone could produce, indicating that an additional mechanism is influencing its motion. This mechanism is as yet unexplained by the scientific community.

In normal comets, this kind of anomaly is often caused by jets of gas from evaporating ice, but in this case, the effect seems much more intense than normal, leaving scientists baffled.

More recently, a group of scientists have been investigating the gas clouds observed around the comet and the associated visual changes.

These studies led to an article published last week in arXiv, an open-access repository for scientific prepublications.

The article in question: Rapid Brightening of 3I/ATLAS Ahead of Perihelion by Qicheng Zhang and Karl Battams. They question the appearance of brightness just before perihelion. Perihelion here represents the point on the comet's trajectory closest to the Sun.

3I/ATLAS has a coma (being the envelope of dust/gas around it) or tail that doesn't quite resemble what we usually see in comets approaching the Sun. What's more, a bluer hue was also observed at perihelion.
This reinforces the hypothesis of an emission of matter (ice/gas): this outgassing could act like a natural "rocket", provoking a thrust that slightly modifies the trajectory.

Several hypotheses are currently being debated within the scientific community.

The first suggests that the comet's acceleration is indeed due to the outgassing of matter, as mentioned above, but in unusual proportions or conditions.

Another, more exotic, hypothesis is that this non-gravitational acceleration could be the sign of an internal or artificial mechanism present within the comet - some even going so far as to suggest the possibility of an engine.

This second idea would be supported by the comet's unusual color and unusual trajectory. It should be stressed, however, that this interpretation remains highly speculative, more a matter of conjecture than scientific proof at this stage.

Avi Loeb, physicist at Harvard University, points out that it is essential to observe the comet's size after its passage behind the Sun: if its diameter remains unchanged, this could indeed raise new questions due to the thermal effects likely to alter its structure.

according to scientists, 3I/ATLAS is above all an exceptional interstellar object that could hold essential keys to the formation of solar systems and to those cosmic travelers who wander between the stars.

According to Avi Loeb, its passage through our solar system represents an unprecedented opportunity to directly analyze matter from elsewhere. The challenge becomes even more fascinating if its enigmatic characteristics are evidence of a totally new phenomenon, revolutionizing our vision of celestial objects. These multiple anomalies challenge our established theories and force us to reconsider the extent of our knowledge.