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Why might humanity be listening for extraterrestrial signals in the wrong way?

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artist's conception of Kepler-186f — extraterrestrial intelligence An artist's conception depicts Kepler-186f, the first Earth-sized extrasolar planet found in its star's habitable zone.

Humanity’s search for extraterrestrial intelligence, known as SETI, primarily focuses on detecting electromagnetic signals, such as radio or light, because they travel at the speed of light and require relatively modest energy to transmit.1

However, some researchers argue that relying solely on radio waves may be limiting. While radio is efficient for communicating information across vast distances, it tends to disperse over time. In contrast, some engineers have suggested that sending physical artifacts—essentially a "message in a bottle"—could be a more effective technique, as these objects retain information in a compact form and are more likely to remain readable upon arrival, even if they travel significantly slower than light.2

Furthermore, the challenge of SETI lies in the unknown variables of an advanced civilization. We may be looking in the "wrong" way by making anthropocentric assumptions about the frequency, target, or character of messages. Because advanced civilizations might possess sciences and techniques currently unknown to 21st-century humans, our current methods may be too narrow to detect signals that do not conform to our specific technological expectations.2