Are aliens sending signals? Scientists look for radio waves not studied before
This high-stakes quest has yet to yield any evidence of intelligent beings beyond earth
(Web Desk) - For over half a century, astronomers have scoured the cosmos for signs of extraterrestrial life, focusing on the detection of technosignatures — distinct electromagnetic emissions that could indicate the presence of advanced alien technologies.
Despite decades of research and the growing belief that the ingredients for life are widespread throughout the universe, this high-stakes quest has yet to yield any evidence of intelligent beings beyond Earth.
The traditional approach to the Search for Extraterrestrial Intelligence (SETI) has involved scanning the skies with large single-dish telescopes at frequencies above 1 GHz.
However, a new frontier is emerging as scientists turn their attention to the relatively uncharted radio window below 1 GHz.
This shift in focus comes with the understanding that if an extraterrestrial civilisation were trying to make its presence known, it would likely transmit signals that stand out from natural background noise.
Radio frequencies have long been considered a promising avenue for SETI because of their use in human telecommunications and radar.
The logic follows that alien civilisations might similarly employ radio waves to communicate or signal their existence.
Consequently, radio astronomy has been integral to SETI since the 1960s, with numerous surveys seeking narrowband radio emissions that could be either intentional transmissions or inadvertent leaks from extraterrestrial sources.
Now, astronomers are expanding the search to include low-frequency signals in the 110–190 MHz range—a spectrum that has seen limited exploration due to challenges such as ionospheric interference.
This initiative represents a significant departure from previous efforts, which have predominantly targeted higher frequencies.
A recent study led by Professor Evan Keane from Trinity College Dublin, in collaboration with the Breakthrough Listen project and Onsala Space Observatory, has demonstrated the potential of multisite simultaneous observations to filter out human-made signals and hone in on possible technosignatures from afar.
Utilising the Irish and Swedish LOFAR stations, the team conducted a sweeping survey of 1.6 million star systems identified by the Gaia and TESS space missions.
While these searches have not yet detected a definitive signal from intelligent extraterrestrial life, the dedication to probing new segments of the radio spectrum and the upcoming enhancements to the LOFAR array signal a renewed vigor in the SETI community.