Scientists Scanned 3I/ATLAS for Alien Signals. Here’s What They Found
As this interstellar object approached its closest point to Earth, a massive radio telescope attempted to sniff out a technosignature.
From the moment astronomers discovered interstellar object 3I/ATLAS, they became fixated on one question: What is it? Months of research have led to overwhelming scientific consensus that it is a comet from beyond our solar system, yet some still speculate that this cosmic visitor isn’t natural at all.
In July, shortly after the discovery, Harvard astronomer Avi Loeb and colleagues proposed that 3I/ATLAS could be an alien spacecraft. Even as studies have contradicted this hypothesis, Loeb has continued to suggest that 3I/ATLAS may be technological. To set the record straight, astronomers recently conducted a “technosignature search” of the interstellar object, essentially scanning it for artificial radio signals.
The study, which has yet to be peer reviewed, found “no credible detections of narrowband radio technosignatures originating from 3I/ATLAS.” In other words, the chances of this object being anything other than a comet are slim to none.
Silence from 3I/ATLAS
The Breakthrough Listen program conducted its technosignature search as 3I/ATLAS neared its closest point to Earth on December 18. Breakthrough Listen claims to be the largest ever scientific research program aimed at finding evidence of civilizations beyond Earth.
For this search, researchers used the Robert C. Byrd Green Bank Telescope (GBT) in Green Bank, West Virginia. This 328-foot (100-meter) steerable radio telescope is the largest moving structure on land. It’s a key asset to SETI (Search for Extraterrestrial Intelligence) research, using its extreme sensitivity to scan distant celestial objects for artificial radio signals.
“There is currently no evidence to suggest that [interstellar objects] are anything other than natural astrophysical objects,” the study authors wrote. “However, given the small number of such objects known (only three to date), and the plausibility of interstellar probes as a technosignature, thorough study is warranted.”
GBT scanned 3I/ATLAS from a distance of about 167 million miles (269 million kilometers), making observations that spanned four bands of the radio spectrum. At first, their search yielded 470,000 potentially artificial signals, but the researchers eliminated all but nine because they also appeared when the telescope pointed away from 3I/ATLAS. Those remaining candidates were later ruled out as human-made radio interference.