Why we might be looking for aliens in the wrong places

Space · Published 21 October 2026 Swipe more like this →

In short: For decades, our search for extraterrestrial intelligence has focused on a specific 'quiet' zone of the radio spectrum. However, new research suggests that by ignoring higher frequencies, we may be missing signals from advanced civilizations simply because we haven't looked in the right places yet.

For years, the Search for Extraterrestrial Intelligence (SETI) has primarily targeted the 'water hole'—a region of the radio spectrum between 1.42 and 1.66 GHz. This area is considered a logical meeting point for interstellar communication because it sits between the natural radio emissions of hydrogen and hydroxyl, the two elements that combine to form water. The assumption is that an advanced civilization would recognize these natural markers and choose this quiet corridor to transmit data. This specific frequency range is often described as a relatively narrow slice of the radio spectrum. Scientists have long viewed this quiet zone as a potentially logical meeting place for interstellar communication.

Louisa Mason, a University of Manchester PhD student, questions this restricted perspective in her latest study. Mason performed the initial SETI search for the Chilean Atacama Large Millimeter/submillimeter Array (ALMA) by employing stored records. Rather than requesting new telescope time, she analyzed existing observations originally collected for unrelated astronomy research. Her goal was to explore the millimeter and submillimeter radio bands, which remain almost completely unexplored for SETI purposes. Mason focused on two narrow frequency ranges within the observatory's Band 3 observations. She specifically looked for narrowband radio signals, which are more consistent with artificial technology than natural space processes.

While the survey—which examined only four archived observations—did not identify any candidate technosignatures, it proved a vital point: even a small number of telescope observations can include millions of stars. The study suggests that searching beyond the 'water hole' opens up a massive new area of parameter space. It highlights that while we haven't found a signal yet, our current search parameters may be far too limited to capture the full scope of potential technological signatures in the universe. During Birmingham's National Astronomy Meeting, the Royal Astronomical Society hosted a presentation of these results. These results indicate that high-frequency telescopes could become useful tools for future SETI efforts.

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