A NASA scientist has proposed an unexpectedly down-to-Earth solution to one of astronomy’s most enduring mysteries: why we’ve never heard from other alien civilisations.
In the study, which was published on the preprint server arXiv and is yet to be peer-reviewed, Dr Robin Corbet of the University of Maryland and NASA’s Goddard Space Flight Centre argues that the answer could simply be “mundane”.
Corbet's theory offers a unique, if somewhat disappointing, answer to the Fermi paradox, which asks why, in a Universe vast enough to host countless potentially habitable worlds, we’ve found no clear evidence of intelligent extraterrestrial life.
Rather than assuming that advanced civilisations are hiding from us, are transcendent beings we can't begin to understand, or have simply gone extinct, Corbet suggested that alien societies might plateau at modest technological levels and even grow bored with exploration.
Applying a theory of what he called 'radical mundanity', Corbet wrote that “the most mundane explanation(s), if physically feasible, is/are are most likely to be correct.”
In this “less terrifying” Universe, there may be a modest number of technological civilisations scattered through the Milky Way, none of which have achieved or desired the galaxy-spanning capabilities imagined by science fiction.
That means no Dyson spheres, no planet-wide laser beacons and no fleets of probes zipping across the vastness of space.
Even if interstellar travel were technically possible, Corbet wrote, “the benefits obtained must outweigh the cost and potential risks.”
Eventually, any civilisation might find that “not much new was found from each encounter” with other alien civilisations and lose motivation to keep searching – a galactic version of scientific burnout.
Corbet likened this to a form of cosmic habituation, where “a creature’s response to a repeated stimulus diminishes”. If most civilisations hit a technological ceiling, they might decide that sending probes or beacons across the Galaxy is simply pointless, not worth the effort or dangerous.
In such a world, humanity’s own radio searches would likely detect only weak “leakage” signals rather than deliberate messages.
“A detection… may not be too far off, historically speaking,” Corbet concluded.
“Although this would have profound implications in many ways, it may not lead to a huge gain in our technology level, and could leave us somewhat disappointed.”
In other words, the Galaxy may be full of life, just not of the kind that finds us very interesting.
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