An international team led by the SETI Institute has found no evidence of alien technology in interstellar comet 3I/ATLAS after conducting radio scans from a telescope in California, scientists confirmed on Wednesday.
PBS reported that the analysis focused on signals picked up from the object as it passed through the Solar System, with researchers concluding that the readings were consistent with natural space activity rather than artificial transmission.
The findings come after months of scientific interest in 3I/ATLAS, only the third known interstellar object ever detected entering our Solar System. First identified last summer, the comet quickly drew attention not just for its unusual origin outside our star system, but also for the speculation—unsupported by evidence—that it could carry signs of intelligent design.
Comet 3I/ATLAS After SETI Observations
For context, 3I/ATLAS was tracked as it passed deep through the inner Solar System, including a close swing past Mars at a distance of around 19 million miles, before reaching its nearest point to Earth in December at roughly 167 million miles away. While close in astronomical terms, scientists emphasise that it posed no risk to Earth at any stage.
The SETI Institute carried out more than seven hours of observations shortly after the comet's discovery, using a radio telescope in Northern California to scan for any structured or repeating signals that might indicate technological origin. According to the team, the system recorded nearly 74 million narrow-band signals during the search.
However, the vast majority of those signals were quickly ruled out as interference from Earth-based systems or satellites in orbit. After filtering, only just over 200 signals remained under review—and even those were traced back to human-made technology rather than anything originating from the comet itself.
The results have now been published in the Astronomical Journal, reinforcing the scientific consensus that 3I/ATLAS is a natural object, most likely an ancient comet formed in another star system before drifting into interstellar space.
No Signs Of Artificial Origin
SETI researchers said the findings highlight both the sensitivity and limitations of current detection methods. Valeria Garcia Lopez of Furman University, a co-author of the study, noted that the data show how easily modern instruments can pick up signals that initially appear unusual but ultimately trace back to known sources.
'That is why it is important to keep searching for technosignatures, even from objects we might not expect to have signals,' she said in a statement.
The lead author, SETI scientist Sofia Sheikh, also pointed out that human-made spacecraft such as NASA's Voyager probes will one day leave the Solar System and become interstellar objects themselves, drifting into other star systems. The implication, researchers say, is that the idea of technological debris moving between stars is not impossible, but simply not evidenced in this case.
Voyager 1 and Voyager 2, launched in the 1970s, are currently the most distant human-made objects in space, continuing their slow journey beyond the reach of the Sun's influence.
What is 3I/ATLAS Made of?
At its estimated size, between 1,444 feet and 3.5 miles across, 3I/ATLAS is thought to be a frozen relic possibly more than 11 billion years old, predating the formation of the Sun itself. Scientists believe it is now heading back into interstellar space, never to return.
NASA spacecraft observed the comet as it passed Mars, while SETI's analysis focused specifically on whether any unusual radio emissions could suggest something beyond natural comet activity. None were found.
While occasional speculation has followed interstellar objects since their discovery, researchers emphasise that every confirmed case so far has pointed firmly to natural origins. 3I/ATLAS now joins that short list, closing another brief chapter in the search for possible extraterrestrial technology, at least for now.
