A recent scan of the interstellar comet 3I/ATLAS by the Breakthrough Listen project revealed no signs of radio-transmitting technology. Utilizing the highly sensitive 100-meter Green Bank Telescope, researchers monitored the comet for several hours just before it reached its closest approach to Earth on December 19, 2025. Despite detecting numerous signals, none were linked to the comet, confirming its classification as a typical comet without any artificial signals.
3I/ATLAS was first discovered on July 1, 2025, and its trajectory indicated it originated from beyond the Solar System. The comet made its closest approach to the Sun, known as perihelion, in late October, before nearing Earth, or perigee, approximately two months later. At perigee, 3I/ATLAS was situated about 270 million kilometers (or 168 million miles) from our planet, which, while nearly twice the distance from the Earth to the Sun, was still close enough for detailed observations.
Search for Technosignatures
On December 18, a team led by astronomer Ben Jacobson-Bell from the University of California, Berkeley employed the Green Bank Telescope to listen for potential radio signals from 3I/ATLAS. During a five-hour observation window, the team aimed to identify any artificial technosignatures. To ensure the signals detected were indeed from the comet, the team alternated observations between the comet and other regions of the sky in a fractal pattern known as an ABACAD arrangement, switching locations every five minutes.
After filtering out signals originating from other areas, researchers identified nine candidate signals. However, closer examination revealed that these signals were merely radio-frequency interference from human technology on Earth, rather than evidence of extraterrestrial communication.
While the lack of signals from 3I/ATLAS does not categorically eliminate the possibility of alien technology, it aligns with existing evidence. 3I/ATLAS exhibits characteristics consistent with a comet, leading NASA Associate Administrator Amit Kshatriya to state, “This object is a comet. It looks and behaves like a comet, and all evidence points to it being a comet.” He emphasized the significance of this comet, noting its origin from beyond our Solar System.
The Importance of Scientific Inquiry
Despite the absence of evidence pointing to alien technology, the search itself is an integral part of scientific exploration. As Kshatriya noted, even negative results can contribute valuable insights. The absence of signals from 3I/ATLAS reinforces the understanding that it is not an alien beacon broadcasting messages across the Solar System.
Looking for potential signals from 3I/ATLAS underscores the scientific principle of inquiry. The possibility of missing a significant discovery due to preconceived notions highlights the need for thorough investigation. Physicist Paul Ginsparg of Cornell University remarked on the broader implications of such research, explaining that discussions surrounding these observations engage the public and inspire future scientific advancements.
The findings from this observational campaign are available on the preprint server arXiv, contributing to the ongoing dialogue in the scientific community regarding the search for extraterrestrial life. While 3I/ATLAS has not yielded evidence of alien technology, its study continues to fuel curiosity and exploration in the field of astronomy.
