What if we’ve been picturing extraterrestrial civilizations all wrong?
Three of the video posters from IAUS404: Advancing the Search for Technosignatures each chipped away at a different assumption baked into the modern search for alien technology.
Robin Corbet asks whether the galaxy might simply hold a modest number of civilizations with fairly ordinary technology, rather than godlike engineers. Milton de Souza Mendonça, Jr. wonders whether truly advanced societies would look less like empire-builders and more like restoration ecologists, quietly undoing their own damage. And Mark A. Schneegurt proposes that the most advanced civilizations might not leave a physical trace at all, if their most important activity has moved somewhere science can’t yet measure.
Different disciplines, same nagging question, and that’s part of what these three researchers presented at IAUS404: Advancing the Search for Technosignatures in March 2026.
Robin Corbet: A Less Terrifying Universe?
Robin Corbet is a senior research scientist at the University of Maryland, Baltimore County’s Center for Space Sciences and Technology, with a joint appointment in the X-ray Astrophysics Laboratory at NASA’s Goddard Space Flight Center. His talk built on a paper he published in The Open Journal of Astrophysics, applying what he calls a principle of “radical mundanity” to the Fermi paradox: the puzzle of why, given how many stars and how much time the galaxy has had, we haven’t found any sign of other technological civilizations.
Rather than reaching for exotic explanations, Corbet’s mundanity principle borrows from the Copernican idea that humanity isn’t special, and asks what the least dramatic answer might be. His conclusion is that the galaxy likely holds a modest number of civilizations, on the order of 10,000 to 100,000, none of which has broken through to a fundamentally new tier of technology the way humans once broke through with electricity. Self-replicating probes, he argues, would still be sent out to explore, but interest and funding would fade as returns diminish and each newly discovered civilization looks more and more like the last one. Long-duration, high-power beacons and Dyson spheres are unlikely; leaked radio and light “leakage” from ordinary activity is the more plausible signature, and current instruments should already have caught some of it if it exists in the way we’ve assumed. That absence, Corbet suggests, is itself informative.
Milton de Souza Mendonça, Jr.: Restoration Ecology and “Hippie Aliens”
Milton de Souza Mendonça, Jr. is a full professor in the Department of Ecology at the Federal University of Rio Grande do Sul (UFRGS) in Brazil, with a PhD from Imperial College London and postdoctoral stints at the University of South Florida and, more recently, a sabbatical at UCLA. His primary research is in invertebrate ecology and insect biodiversity, with astrobiology as what he describes as a side interest, or as he put it in his talk, “in the spare time.”
That side interest produced a talk built on restoration ecology, the applied science of nudging degraded ecosystems back toward their pre-disturbance state.
Mendonça’s argument is that any civilization advanced enough to avoid environmental collapse, a leading candidate for a “Great Filter” that wipes out young technological species, would likely have to become skilled at exactly this kind of ecological repair. If so, we should expect “hippie aliens”: civilizations that trend toward preserving and restoring their home biospheres rather than paving over them. He drew on a 2025 scenario-modeling study by Jacob Haqq-Misra, George Profitiliotis, and Ravi Kopparapu, which mapped ten possible thousand-year futures for Earth’s technosphere, to argue that environmental factors deserve more explicit weight in that kind of forecasting. One consequence for technosignature hunters: pollution and other planetary technosignatures could be short-lived, cleaned up quickly by societies motivated to survive, leaving a narrow window for detection and shifting the more durable signs of a civilization’s presence out into space rather than on the planet’s surface.
Mark A. Schneegurt: Detecting a Technosphere by Its Emergent Pneumasphere
Mark A. Schneegurt is a professor in the Department of Biological Sciences at Wichita State University, where his research centers on microbiology and astrobiology, including work on how microbes survive in the extremely salty, low-water environments that may resemble conditions on Mars and other ocean worlds. He has collaborated for years with NASA’s Jet Propulsion Laboratory on questions of habitability at the edges of life.
His IAUS404 poster took a considerably more speculative turn. Building on the biologist and geochemist Vladimir Vernadsky’s century-old model of the geosphere giving rise to the biosphere, which in turn gives rise to the noösphere (the realm of reasoned human thought), Schneegurt proposed a further layer he calls the pneumasphere: a domain of creative, intuitive, and “extraphysical” experience that he argues sits beyond logic and isn’t bound by the rules of physics as science currently understands them. His premise is that a mature technosphere frees up the time and stability for a civilization to explore this inner space, and that as it becomes a planetary-scale phenomenon, it might open an entirely different channel for detecting, or even communicating with, other worlds. It’s a framework built explicitly outside the conventional bounds of the scientific method, and it remains a personal, exploratory hypothesis rather than an established or testable model. Since the talk, Schneegurt’s own published list of works in progress includes a manuscript on the concept submitted to the journal Fundamentals of Science, not yet peer-reviewed or published as of this writing.
Key Takeaways
Robin Corbet’s “radical mundanity” principle suggests the Fermi paradox may not need an exotic solution: a modest number of civilizations with ordinary, plateaued technology could explain the silence just as well as a lonely galaxy would.
Corbet’s framework predicts no long-duration alien beacons and no Dyson spheres, but holds out a real, if bittersweet, chance of catching faint “leakage” signals within a few generations.
Milton de Souza Mendonça, Jr.’s “hippie aliens” hypothesis flips a common assumption: civilizations that survive long-term may be defined by ecological restraint and repair, not unchecked expansion.
That same hypothesis implies planetary technosignatures like pollution could be short-lived and hard to catch, pushing the search toward off-world technosignatures instead.
Mark A. Schneegurt’s “pneumasphere” concept is a frankly speculative proposal that some technosignatures might not be physical at all, a reminder that not every idea presented at a symposium like this is meant to be settled science.
Together, these three posters push at the edges of a search that usually runs on radio telescopes and spectrometers: one recalibrating how many civilizations we should expect and how visible they’d be, one asking whether survival itself might look ecologically humble rather than expansive, and one wondering aloud whether some signs of intelligence might sit outside what any instrument can register. Readers curious to go deeper could start with Corbet’s own paper in The Open Journal of Astrophysics or the Haqq-Misra, Profitiliotis, and Kopparapu technosphere scenarios Mendonça cited, both freely available.
These videos were included in the proceedings of the International Astronomical Union (IAU) symposium #404, Advancing the Search for Technosignatures, hosted by Blue Marble Space.
Thanks for joining us here with Planetary Perspectives, an editorial endeavor and science communication project from Blue Marble Space.
M. Schneegurt's speculation is interesting. It's a shame that one of his papers, titled “The Pneumasphere as an Emerging Property of the Noosphere and Its Implications for Astrobiology,” is no longer available on the Wichita State University website.