Radio scans find no alien tech from the latest interstellar comet

This image provided by NASA shows the interstellar comet 3I/Atlas captured by the Hubble Space Telescope on Nov. 30, 2025. (NASA, ESA, STScI, D. Jewitt (UCLA), M.-T. Hui (Shanghai Astronomical Observatory), J. DePasquale (STScI) via AP, File)

CAPE CANAVERAL, Fla. — The group leading the charge in the search for extraterrestrial life has given the all clear: An interstellar comet looks to be completely natural and free of any alien tech.

The SETI Institute said Wednesday that extensive radio scans by its telescope in Northern California found no signs of otherworldly technology from our solar system’s latest interstellar visitor.

The object labeled 3I/Atlas was discovered last summer sweeping through our neck of the cosmic woods. Scientists quickly identified it as a comet that migrated from another star, although a few insisted without evidence it might be associated with intelligent life.

• READ MORE: New images of mysterious interstellar object 3I/Atlas released by Europe’s space agency
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It’s only the third known object from a faraway star — all deemed of natural origin — to venture into the sun’s turf.

Several NASA spacecraft observed the celestial iceball as it swung past Mars last October, venturing within 19 million miles (30 million kilometres) of the red planet. The closest it ever got to Earth was in December at a whopping 167 million miles (269 million kilometres) away.

SETI said it conducted more than seven hours of observations in July soon after the comet was discovered, searching through a wide range of radio signals. The team identified nearly 74 million narrow-band radio signals.

After accounting for human interference or signals matching the object’s movement, only slightly more than 200 signals remained, all of which “traced back to technology on the surface of the Earth or our own Earth-orbiting satellites,” according to SETI.

Results were published in the Astronomical Journal.

These results “show how realistic it is to detect a signal with the technology we have today,” co-author Valeria Garcia Lopez of Furman University said a statement. “That is why it is important to keep searching for technosignatures, even from objects we might not expect to have signals.”

SETI’s Sofia Sheikh, the lead author, and her team pointed out that NASA’s Voyager spacecraft will one day become extraterrestrial objects in neighboring star systems. Launched in the 1970s, the twin probes are the most distant spacecraft from Earth, drifting in the space between stars.

“Voyager and similar probes will eventually become interstellar objects in other stellar systems. We thus know that no extrapolation is needed for the idea of interstellar technological objects, as we have a proof by existence,” they wrote.

Almost 1 billion miles away now (1.3 billion kilometres) as it makes its way back to interstellar space — never to return — the comet is estimated to be within 1,444 feet (440 metres) and 3.5 miles (5.6 kilometres) in size. Scientists suspect it could be as old as 11 billion years, twice as old as the sun.

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Marcia Dunn, The Associated Press