Interstellar Comet 3I/ATLAS emits rare metal alloy, says Harvard expert

Comet Lemmon (Image: Victor Sabet & Julien De Winter/NASA)

An enigmatic interstellar body, 3I/ATLAS, is again causing intrigue as it passes through our solar system. NASA has assured that the comet is not a threat, but its peculiar characteristics have scientists bewildered.

What Makes 3I/ATLAS So Unusual?

The object was first discovered on July 1, and new observations have revealed surprising data. According to a report by the New York Post, Harvard astrophysicist Dr Avi Loeb said the comet emits a metal alloy never before seen in nature. The discovery was made using the Keck II telescope in Hawaii, which captured new images in August.

Researchers found the comet releases a plume containing about four grams of nickel per second, with no traces of iron. The Keck II data showed distinct nickel and cyanide emissions stretching hundreds of kilometres from the comet’s nucleus. The findings were shared in a study posted on the preprint server arXiv, though not yet peer-reviewed.

Could It Be of Technological Origin?
The study authors noted that the nickel emissions are more concentrated in the comet’s core, hinting at compounds that may form easily dissociated species like metal carbonyls or metal-polycyclic-aromatic-hydrocarbon molecules. What caught scientists’ attention was that nickel emissions without iron are common in industrially made alloys, but never in comets.

“There is only one place where that is known to exist, and that is in industrially produced nickel alloys,” Dr Loeb told The Post. He added, “This was never observed for any other object.” His comments have fuelled speculation that 3I/ATLAS could have a technological origin rather than a natural one.

What Else Have Astronomers Found?
3I/ATLAS is the third known interstellar visitor after 1I/‘Oumuamua and 2I/Borisov. In most comets, nickel and iron appear in similar amounts, but 3I/ATLAS breaks that rule. Astronomers have also observed an unusual “anti-solar tail,” which appears to point towards the Sun instead of away from it.

Dr Loeb said, “We usually see beautiful tails extending from the object away from the Sun, and in this case there was no evidence for such a tail.”

The comet is expected to reach its closest approach to the Sun on 29 October 2025, at about 1.36 astronomical units. As scientists continue to study it, the mystery of 3I/ATLAS deepens—leaving many to wonder whether it is merely a cosmic traveller or something far more advanced.