Welcome, dear readers of FreeAstroScience. Here’s our central question: if life is out there, why haven’t we noticed it yet? Today we explore a striking proposal—“radical mundanity”—that reframes the Fermi paradox. The idea is simple and a little humbling: perhaps the Galaxy holds only a modest number of technological civilizations, and none have built galaxy-spanning megastructures or timeless beacons. We’ll unpack the new paper behind this idea, pressure-test its logic with quick math, and sketch what observatories could find next. This article is written by FreeAstroScience only for you—stick with us for the full picture and a couple of ‘aha’ moments.
What is “radical mundanity,” and why should we care?
A new preprint by Robin H. D. Corbet (UMBC / NASA GSFC) argues that the most non-extreme, physically plausible explanations deserve priority: the Milky Way likely hosts a non-zero but modest number of technological civilizations (ETCs), each capped by down-to-earth technology—advanced beyond us, yes, but far from “super-science.” That would neatly explain the Great Silence: no Dyson spheres, no omnipotent probes, no eternal beacons—just faint “leakage” signals that are hard to catch.
Universe Today covered the study on October 31, 2025, highlighting its practical implications for SETI and quoting Corbet’s forecast: with facilities like the Square Kilometre Array (SKA), a detection via leakage radiation might be “not too far off, historically speaking.”
How do we even measure “advanced”—power, brains, or something else?
Is the Kardashev scale still useful?
The Kardashev scale tracks energy use: Type I (planetary), Type II (stellar), Type III (galactic). Corbet notes it’s crude yet serviceable; alternatives exist (information capacity, manipulation scale, machine intelligence) but are harder to pin down. Crucially, mundanity says no one achieves the extreme ends—no sweeping Type II/III feats we’d easily see.
| Scale | What it measures | Mundanity takeaway |
|---|---|---|
| Kardashev | Power usage (Type I–III) | ETCs stay below obvious mega-engineering |
| Sagan/Info | Stored/processed information | Hard to infer remotely |
| Barrow/Nano | Minimum scale of manipulation | Invisible at interstellar distances |
If tech plateaus, what projects vanish—and which signals remain?
Could megastructures be impossible, pointless, or both?
Mundanity pairs two constraints: limited means and limited motive. Even if a Dyson sphere were technically feasible (a huge “if”), a civilization might not need star-level power or might find the risk/cost unacceptable. So our surveys shouldn’t expect bright, durable infrared excesses from galaxy-wide Dysonization. That aligns with mixed and contested Dyson-candidate lists so far.
Where are the loud, long-lived beacons?
Maintaining a millions-year beacon co-located with a civilization is economically and politically hard to justify. The power bill is enormous, and if you’re patient enough to transmit for a galactic crossing time, why not send probes instead? Mundanity predicts no long-duration, high-power beacons at home bases—at best, occasional or remote transmitters.
So what’s left to find?
Leakage: unintentional radio emission from ordinary activities. Corbet argues SKA-class facilities could detect an Earth-analog out to ~200 pc under favorable assumptions. That’s our most promising near-term win. Cue the aha moment: the first signal we catch may be underwhelming—prosaic radio “hum,” not a grand hello—but still epoch-making.
Wouldn’t self-replicating robots colonize everything anyway?
Mundanity pushes back: motive matters. If visiting thousands of similar M-dwarf systems yields diminishing scientific returns, expansion stalls—especially if people worry about “Berserker” risks from autonomous probes. Corbet formalizes this with a toy model that stops exploration once you’ve met Nennui other ETCs.
Quick, transparent math (yes, we checked the units)
Let the Milky Way’s habitable “slab” have radius (r_{\rm MW}) and height (h_{\rm MW}). If there are (N_{\rm MW}) plateau-level ETCs, the mean number density is:
If probes expand at speed (s_p) for time (T) (including replication cadence), then the expected number of ETCs encountered inside the expansion volume is approximately:
A worked example from the paper’s scaling: with (N_{\rm MW}=10^5), (s_p=10^{-3}c), and (T\sim10^6) years, you meet only a few ETCs. Hitting (N_{\rm ennui}\sim100) takes ~Myr at sub-relativistic speeds, and you still explore only a tiny Galactic fraction. This is fast astronomically, yet limited sociologically.
| Symbol | Meaning | Illustrative value | Consequence |
|---|---|---|---|
| NMW | Number of ETCs in Milky Way | 104–105 | Average spacing large; leaks are faint |
| sp | Probe expansion speed | 10−3c | Myr timescales to meet ~100 ETCs |
| Nennui | “We’re bored/it’s risky” threshold | ~100 | Exploration halts; no full colonization |
What does mundanity predict we’ll (not) see?
- No confirmed Dyson spheres; astrophysical explanations win.
- No long-duration, co-located beacons; any “hello” is sporadic or remote.
- Rare or absent galaxy-wide probe waves; localized exploration at best.
- Best bet: detect leakage radio with SKA or the next generation after it.
Where do famous puzzles land under mundanity?
Corbet’s review situates well-known candidates—radio “Wow,” Tabby’s Star dimmings, ‘Oumuamua, and UAP claims—within ordinary astrophysics and sociology. None, so far, demand super-advanced engineering or visiting craft. That is exactly what mundanity expects: intriguing false alarms and natural phenomena at scale.
Which grand narratives does the data actually favor?
| Civilizations | Tech level | Prediction | Status vs. observations |
|---|---|---|---|
| Many | Very high | Megastructures, beacons, probes everywhere | Not seen → tension |
| Few | Very high | Eager outreach; detectable artifacts | Not seen → tension |
| Many | Mundane | No megastructures; possible nearby leaks | Consistent so far |
| Few | Mundane | Silence very likely | Also consistent, but violates mediocrity |
What should we try next—this decade?
- Go deep for leakage: SKA and ngVLA push sensitivities where ordinary emissions at 100–200 pc become marginally visible. That’s where a first hit may lurk.
- Keep calm on megastructures: scrutinize IR excesses, but expect mundane astrophysics to dominate.
- Biosignature telescopes: HWO/LIFE-class missions could show that life is common even if tech is modest—another mundanity signal.
So…is a less terrifying Universe actually more interesting?
Here’s the twist. A “mundane” Galaxy might be teeming with life yet quiet in technosignatures. We may find neighbors who are clever but not omnipotent, curious but cautious. That picture isn’t bleak; it’s relatable. It says we matter, because our choices and telescopes change what we learn next. The first detection might be a whisper, not a trumpet—but it would still redefine our place in the cosmos.
Conclusion
We asked whether a mundane Universe could solve the Fermi paradox. The answer we explored is yes, plausibly: a modest number of ETCs, each at a modest tech plateau, yields few beacons, no clear megastructures, and a realistic chance to detect leakage with SKA-class instruments. That scenario respects the data, sidesteps extreme stories, and keeps discovery on the table. Before we chase monsters, we should master murmurs.
This post was written for you by FreeAstroScience.com, where we explain complex science simply and spark curiosity—because the sleep of reason breeds monsters.
Sources and further reading
- Corbet, R. H. D. “A Less Terrifying Universe? Mundanity as an Explanation for the Fermi Paradox” (arXiv:2509.22878v1, Sept 26, 2025).
- Universe Today coverage by Laurence Tognetti (Oct 31, 2025).
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