During the close approach of comet 3I/ATLAS, researchers took the chance to look for signs of alien life. The Breakthrough Listen project aimed to detect technosignatures, or signals that might suggest intelligent life is out there. They used powerful radio telescopes to scan for anything unusual.
3I/ATLAS was first spotted by the Asteroid Terrestrial-impact Last Alert System on July 1, 2025. It’s an interstellar object, meaning it comes from a different region of our galaxy. Scientists quickly identified it as a comet because of its classic features. This comet is likely older than our Solar System and might not have visited our neighborhood for around 10 million years.
The speculation around the possibility of it being an alien spacecraft has intrigued many. Harvard astrophysicist Avi Loeb believes that, while such ideas are exciting, 3I/ATLAS is probably just a regular comet. Still, the curiosity led scientists to perform a check.
On December 19, 2025, when the comet was about 167 million miles away from Earth, scientists employed the Green Bank Telescope, one of the largest steerable radio telescopes, to seek out signals. They scanned various frequency ranges, aiming to find anything that suggested communication from extraterrestrial sources.
Despite their efforts, the team found nothing. They documented nine “events” that seemed interesting but later ruled them out as interference from known radio sources. This lack of findings reinforces the idea that there’s no evidence suggesting 3I/ATLAS is anything other than a natural object.
In a separate study, researchers looked into the size of the comet by examining its non-gravitational acceleration. This acceleration occurs when gas and dust are expelled from the comet as it approaches the Sun, causing it to change speed without any external forces. By combining data collected from Earth-based telescopes and space missions, scientists estimate that the nucleus, or core, of 3I/ATLAS is about 1 kilometer across.
As comets heat up, they lose material, affecting their speed and movement. Understanding this helps scientists gauge the size and behavior of these celestial visitors. The recent data suggests that 3I/ATLAS behaves similarly to comets from our own Solar System.
This research contributes to our knowledge of interstellar objects, as only a few have been discovered. Each new object like 3I/ATLAS can inform scientists about different parts of the galaxy and the types of materials and conditions that exist.
In summary, while the search for alien life remains a hot topic, the evidence points to 3I/ATLAS being just another fascinating comet, providing important insights into our universe.
For those interested in the detailed findings, the papers are available on arXiv here and here.
