A new study conducted by researchers at the SETI Institute suggests that space weather conditions around stars could be hindering the detection of radio signals from extraterrestrial civilizations.  

Stellar activity and plasma turbulence near a transmitting planet can broaden an originally ultra-narrow signal, scattering its power across a wider range of frequencies and complicating its identification in traditional narrowband searches.

For decades, numerous SETI program experiments have focused on identifying peaks in the frequency spectrum—signals that are unlikely to be generated by natural astrophysical processes. However, this new research highlights a complication that had gone unnoticed until now: even if an extraterrestrial transmitter produces a perfectly defined frequency signal, it may not retain that characteristic once it leaves its planetary system of origin.

In most technosignature searches, scientists take into account the distortions that radio waves experience during their journey through interstellar space. This study focuses on what happens much closer to the emitting source.

SETI searches are usually optimized to detect extremely narrow signals. If a signal broadens due to the environment of its own star, it can fall below our detection thresholds, even when it is present. This phenomenon could help explain part of the radio silence we have observed in technosignature searches, explained Dr. Vishal Gajjar, astronomer at the SETI Institute and lead author of the paper reporting the research findings.


SOURCES

SETI Institute

Vishal Gajjar and Grayce C. Brown, Exo–IPM Scattering as a Hidden Gatekeeper of Narrowband Technosignatures. ApJ 999 210, DOI 10.3847/1538-4357/ae3d33