3IATLAS confirmed natural comet, no alien signals

Scientists have confirmed that the third known interstellar object to visit our solar system is a natural comet, finding no evidence of alien technology after an extensive radio scan. The object, designated 3IATLAS, was discovered in July 2025 and has since been studied by astronomers worldwide.

Researchers at the SETI Institute conducted more than seven hours of observations using the Allen Telescope Array in Northern California shortly after the comet's discovery. They searched for narrowband radio signals, known as technosignatures, which could indicate the presence of artificial technology. The team identified nearly 74 million such signals but, after filtering out human interference and artifacts caused by the comet's motion, only about 200 remained. All of those were ultimately traced back to terrestrial sources or Earth-orbiting satellites.

The findings, published in The Astronomical Journal, reinforce that 3IATLAS is a natural object. The observations place upper limits on the power of any potential radio transmitter on or near the comet, ruling out signals stronger than approximately 10 watts over the detected frequencies.

Scientists had previously determined the object...