At a Glance
- 3I/ATLAS, the third interstellar object, was searched for alien radio signals.
- The Breakthrough Listen program found no credible technosignatures.
- The object is confirmed as a comet, older, larger, and faster than previous interstellar visitors.
- Why it matters: It rules out a technological origin for 3I/ATLAS and deepens our understanding of interstellar comets.
When astronomers first spotted 3I/ATLAS, the question was whether it was a natural comet or a potential alien probe. A recent technosignature search using the Green Bank Telescope found no evidence of artificial radio signals, confirming its cometary nature.
Technosignature Search
The Breakthrough Listen team scanned 3I/ATLAS with the 100-meter Robert C. Byrd Green Bank Telescope on its closest approach to Earth on December 18. They observed four radio frequency bands from a distance of about 167 million miles (269 million kilometers).
- 470,000 potential signals were initially flagged.
- All but nine candidates were discarded because they also appeared when the telescope pointed away from 3I/ATLAS.
- The remaining nine were later identified as human-made radio interference.
Results and Interpretation
The study authors wrote that there is currently no evidence to suggest that interstellar objects are anything other than natural astrophysical objects. They noted that, given the small number of known objects, a thorough study is warranted.
Study authors
> “There is currently no evidence to suggest that [interstellar objects] are anything other than natural astrophysical objects.”
Study authors
> “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.”
Study authors
> “no credible detections of narrowband radio technosignatures originating from 3I/ATLAS.”
Two other research groups also searched for technosignatures at different frequencies and found no credible artificial radio signals.
Why 3I/ATLAS Matters
Although the comet’s natural origin may disappoint SETI enthusiasts, 3I/ATLAS remains one of the most intriguing discoveries. It is older, larger, and faster than its predecessors and displays unique chemical and physical properties.
| Property | Detail |
|---|---|
| Size | Larger than previous interstellar objects |
| Speed | Faster than previous interstellar objects |
| Age | Older than previous interstellar objects |
| Chemistry | Unique chemical composition |
Key Takeaways
- 3I/ATLAS is confirmed as a comet with no detectable technosignatures.
- The Breakthrough Listen search ruled out artificial radio signals at four frequency bands.
- The object’s unique properties make it a valuable target for studying distant star systems.
As 3I/ATLAS returns to interstellar space, scientists will continue to mine the data, enriching our knowledge of distant star systems.
