Last month, astronomers made an exciting discovery, observing an interstellar object — only the third ever observed — hurtling toward the center of the solar system.

The object, dubbed 3I/ATLAS, has caught the attention of Harvard astronomer Avi Loeb, who has a long track record of making controversial predictions about previous interstellar objects being relics from an extraterrestrial civilization.

While there's been a growing consensus among astronomers that the latest object is a comet, Loeb has continued to entertain the idea that it may have been sent to us by an intelligent species from outside of the solar system — and he's far from backing down.

In a blog post over the weekend, Loeb pointed to observations by NASA's Hubble Space Telescope, which showed a "glow of light, likely from a coma, ahead of the motion of 3I/ATLAS towards the Sun."

A coma is the hazy and luminous cloud that surrounds the nucleus of a comet.

However, there's "no evidence for a bright cometary tail in the opposite direction," he wrote, with scientists suggesting it was evidence that dust was evaporating from the object's Sun-facing side.

The observations led Loeb and his colleagues to an intriguing, albeit far-fetched possibility: is the mysterious space object generating "its own light?"

After deliberations with his colleague and Harvard astrophysicist Eric Keto, Loeb suggested that the "simplest interpretation" of 3I/ATLAS' observed "steep brightness profile" is that its nucleus "produces most of the light."

That would also mean that its actual size is much smaller than currently thought, roughly in line with the size of the first two interstellar objects we've observed, 'Oumuamua and 2I/Borisov.

The Harvard astronomer suggested two possibilities: either 3I/ATLAS is naturally emitting radiation because its a "rare fragment from the core of a nearby supernova that is rich in radioactive material" — or it's a "spacecraft powered by nuclear energy, and the dust emitted from its frontal surface might be from dirt that accumulated on its surface during its interstellar travel."

Loeb deemed the former explanation "highly unlikely," and the latter as requiring "better evidence to be viable."

Loeb previously argued that the object's unusual trajectory — which includes suspiciously close flybys of both Earth and Jupiter — and its lack of a visible tail both undermine the theory that it's a comet.

Intriguingly, 3I/ATLAS will come within spitting distance — at least in astronomical terms — of Mars this fall, giving us a tantalizing opportunity to have a first-hand look. Loeb suggested using NASA's Mars Reconnaissance Orbiter to point its scientific instruments at the rare visitor.

Best of all, scientists at the space agency appear to be game.

"This morning, I encouraged the HiRISE team to use their camera during the first week of October 2025 in order to gather new data on 3I/ATLAS," Loeb wrote. "They responded favorably."

More on the object: Astronomer Suggests New Interstellar Object Could be Advanced Aliens Testing Our Intelligence


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