The SETI Institute, the nonprofit that conducts a search for extraterrestrial intelligence by examining radio waves for artefacts that are unlikely to be the result of natural processes, thinks it may have been going about it the wrong way.
As explained in a paper and post published last week, SETI points out that it has focussed its attention on narrowband signals and tries to compensate for interstellar events that might distort signals.
The organization’s new research points out that solar winds or coronal mass ejections may distort signals within aliens’ star systems. SETI therefore hasn’t been looking for likely signals that We Are Not Alone, because it assumed that alien civilizations transmitted narrowband signals.
“If a signal gets broadened by its own star’s environment, it can slip below our detection thresholds, even if it’s there, potentially helping explain some of the radio silence we’ve seen in technosignature searches,” said Dr. Vishal Gajjar, Astronomer at the SETI Institute and lead author of the paper.
SETI’s researchers made that suggestion after studying data describing signals sent by human-made probes and finding signal distortion on many missions – the paper mentions Mariner IV, Pioneers 6, 10, and 11, Helios 1 and 2, Viking missions to Mars, Mars Express, Venus Express, and Rosetta missions.
The researchers concluded that “broadening can exceed 10–100 Hz for most systems” and suggests that’s enough “to shift otherwise detectable technosignatures below the sensitivity thresholds of current search pipelines optimized for sub-Hz channel.”
The authors think their work “may offer a compelling explanation for the apparent absence of detected narrowband radio technosignatures.”
That’s a hopeful view of the universe, and one supported by the many findings of circumstances that may have already been conducive to life right here in our own solar system.
But it also leaves some room for existential angst for those who hoped their participation in the SETI@home distributed data analysis project might have made a difference, because the organization may have been tuned into the wrong cosmic radio station for decades. ®
