Interstellar object 3I/ATLAS baffles scientists after passing the Sun

Interstellar object 3I/ATLAS baffles scientists after passing the Sun

The interstellar object known as 3I/ATLAS has once again puzzled astronomers after new images taken on November 5 showed no sign of a cometary tail. The observations, captured by the R. Naves Observatory in Spain, contradict what scientists expected to see after the object passed close to the Sun last week, according to a report in the New York Post.

Typically, a comet that swings near the Sun sheds gas and dust that form a bright, sweeping tail. According to Harvard astrophysicist Avi Loeb, the encounter should have stripped away a significant portion of the object’s nucleus. Loeb estimated that roughly 13 percent of its mass should have been visible as debris trailing behind the core as it reappeared in Earth’s view.

Instead, the latest image shows a compact, featureless glow with no visible tail. Loeb said that such behaviour is unusual for a comet and added that the absence of expelled material revives questions about why 3I/ATLAS exhibited non-gravitational acceleration during its approach to the Sun. That unexplained push is one of the reasons some theorists have suggested the object may not be a typical comet at all.

Loeb cautioned that the current viewing angle may be too narrow to reveal a tail if one exists. The object was photographed about ten degrees from the Sun in the sky, a position that can scatter or hide fainter features. As 3I/ATLAS continues to travel outward, the viewing angle will widen and allow more precise measurements. Loeb said this offers a clean test of the object’s true nature. If it behaves like a natural comet, it should soon be surrounded by a large cloud of gas and dust.

For comparison, the same observatory captured an image on November 3 of comet Lemmon, which displayed a prominent, unmistakable tail as it passed through the Solar System. The contrast has further heightened interest in the behaviour of 3I/ATLAS.

The object is now moving away from Earth and is headed toward a close pass by Jupiter on March 16. It entered the Solar System on June 14 and is only the third confirmed interstellar object to visit our neighbourhood. Both NASA and the European Space Agency have orbiters positioned to observe it during this last phase of its journey, though some of the most anticipated images from NASA’s Mars orbiter remain delayed due to the U.S. government shutdown.

If you want a more explanatory version, or a headline aimed at non-science readers, happy to shape it.