Welcome to Bedtime Astronomy. Explore the wonders of the cosmos with our soothing Bedtime Astronomy podcast. Each episode offers a gentle journey through the stars, planets, and beyond, perfect for unwinding after a long day. Let's travel through the mysteries of the universe as you drift off into a peaceful slumber under the night sky.
Are we alone? I mean, it's the ultimate cosmic question, isn't it. It really drives so much of our science, our speculation.
It absolutely does. And for generations of this search for extraterrestrial technological civilizations etcs as we call them, it's been fueled by this image of finding something huge.
Right like beings way way beyond us, cosmic architects, maybe galactic empires, wielding you know, unimaginable power, that kind.
Of thing exactly. That's been the dream. Yet despite all our efforts, better telescopes, more sense searches, the universe is just quiet, very quiet.
And that quiet isn't just a letdown. It's a genuine scientific puzzle, a big one.
It truly is one of the most perplexing.
Really yeah, and that's why we're doing this deep dive today. We've got some fascinating sources suggesting a really different take, almost well, almost simple.
A radical idea in its own way.
Totally. We're going to unpack this concept called radical mundanity. The core idea, maybe the reason we haven't found aliens isn't because they're super rare or hiding, but because they're just well ordinary, Yeah, too mundane for us to notice easily.
And we're digging into the work of doctor Robin Corbett here. His research, it was published on the r arcsoof pre print server, offers this theoretical framework. Okay, he basically investigates the chances of finding etcs if we assume this mundanity idea is correct, and it's vital research because it challenges that whole super science bias in SETI.
Right, it might change what we should even be looking for exactly.
And why we're hearing this cosmic silence.
So it all comes back that famous question from doctor Enrico Fermi way back in nineteen fifty the one we still can't answer, where is everybody?
That question just cuts right to the heart of it, doesn't it the Fermi paradox, It really does, and the paradox itself it's the stark clash between what we expect and what we actually see, or rather, what we don't see.
The expectation comes from the sheer numbers, right, billions of galaxies, billions of stars.
In each hundreds of billions. Yeah, and we now know planets are everywhere, almost every star seems to have them, and loads are in that Goldilocks zone, the habitable zone.
So statistically, even if life is incredibly rare, multiply that tiny chance by the gazillions of planets out there.
You should get a galaxy buzzing with life, and a lot of it should be intelligent technological. Given the billions of years the universe has been.
Around, plenty of time for civilizations to pop up, grow, maybe even spread out. We should see sign somewhere.
That's the expectation, but the observation still zero. Absolutely no definitive proof, no giant alien constructions, no obvious signals, no you know, take me to your leader moments.
Nothing.
It's this gap, the high probability versus the stark quiet reality that pushes fields like astrobiology, SETI exoplanet science forward. We have to figure out why our assumptions don't match what we're seeing.
If that assumption of like cosmic grandeur keeps getting shot down, then something fundamental in our thinking must be off.
And for decades, the answers people came up with for the Fermi paradox tended towards while the sources call them extreme scenarios.
Okay, yeah, let's touch on those briefly, because this new idea is supposed to replace them, right exactly.
So, the first big category is that life is just rare, or it destroys itself. This often involves the idea of the great filter.
The great filter like some massive hurdle that's almost impossible for life to get past.
Right, And maybe that filter is behind us. Maybe just getting life started from non life, or jumping from single cells to complex creatures like us, maybe that was the incredibly rare event. If so, hey, maybe we're first or one of the very few.
That's the optimistic few sort of. Yeah, But the filter could be ahead of us.
Too, right, that's the more chilling possibility. Maybe civilizations inevitably hit a wall, runaway climate change, nuclear war, maybe some kind of out of control AI.
They just snuff themselves out before they can really go interstellar.
Pretty much in that case, advanced civilizations might exist, but they're either incredibly rare or they just don't last very long on a cosmic timescale.
Okay, so that's one set of ideas.
What else, then you've got explanations where life is common but they have reasons to stay quiet. The famous one is the dark forest hypothesis.
Ah, yeah, from science fiction, but scientists discuss it seriously, the idea that the universe is dangerous.
Exactly if resources are limited. Announcing your existence could paint a target on your back. Any new kid on the block might be seen as a threat by older, more established civilizations.
So they practic is extreme radio silence, stay hidden to survive.
Right, which implies they also have the tech to detect others who aren't being quiet and maybe silence them. It suggests a pretty predatory cosmos.
Yikes. Okay, and the last classic.
One, the zoo hypothesis. This one's a bit more benign, but still requires immense technological superiority.
They know we're here, but they're just watching, like we're a cosmic nature preserve sort of.
Yeah, they deliberately avoid contact, maybe following some kind of prime directive not to interfere with our development.
But again that implies. They're so advanced they can enforce this across huge distances. They're essentially galactic zoo keepers.
That's the key point. All these traditional explanations. They rely on extremes, extreme rarity because of a filter, extreme silence, because of danger, extreme power to run a zoo.
They all assume that if a civilization survives past our stage, it becomes some kind of cosmic powerhouse, a super science society, as you said precisely.
But what if that core assumption is wrong. What if the choice isn't just between cosmic gods and total emptiness.
What if most advanced life is well just a bit more advanced than us, not godlike at all.
That's the door radical mundanity opens. But first we need a way to measure advancement, right, ye, a scale.
Right which brings us to Kardashchev.
Exactly to get away from just philosophical handwaving and talk about physics energy. Doctor Corbett's study uses the Kardashev scale. It's a classic model from a Soviet astronomer, Nikolai Kardashchev.
And it basically ranks civilizations by how much energy they can use.
Right, that's the benchmark, that's it purely based on power consumption, which is a fundamental constraint. And it's a logarithmic scale, remember.
Meaning the jumps between levels are enormous. Not just a little bit more power, but orders of magnitude.
More astronomical leaps. So let's start at the bottom room. Type I civilization. This is a civilization that controls all the energy available on its home planet.
So we're talking weather control, tapping all gethermal wind, solar, maybe advanced fusion power, basically managing the entire planet's energy budget.
Total planetary energy management. Yeah, something like ten to the sixteen watts. Humanity, for context, is still climbing towards that. Carl Sagan estimated US around point seven maybe point seventy three. Now we're not quite there yet.
Okay, So Type I is planetary mastery. What's type two?
Type two civilization, Now you take a colossal jump. This civilization harnesses the total energy output of its host star.
It's entire star like our sun.
Yep, for a star like our sun, that's about ten to the twenty six watts. That's ten billion times more energy than a Type I civilization uses. This is where you get into proper superscience man.
The classic image here is the dice in sphere, or maybe a dice and swarm. These massive structures built around the star to capture all its light and heat.
That's the theoretical mechanism. Yes, building something on that scale, it boggles the mind. Structures bigger than planet's completely enclosing a star.
And the crucial point for detection is they couldn't hide this, could they, even if they wanted to.
That's the argument physics demands that energy conversion creates waste heat thermodynamics. Even a super efficient Type two civilization capturing nearly all its stars light.
Would still radiate heat, waste heat exactly.
So instead of seeing a normal star, we'd see something dimmer invisible light, but with this huge unnatural spike in the infrared.
Spectrum, like a giant heat signature where a star should be. Yeah, something that screams.
Artificial, unmistakably artificial, a massive blob of mid infrared radiation. If even one Type two civilization existed in our galaxy and had been around for a while.
We should have spotted that heat signature with our infrared surveys like Wyser Spitzer.
We should have the fact that we've found basically no really convincing candidates for these megastructures. That is the Fermi paradox in action, it deepens the mystery.
Okay, so Type two is stellar mastery, and then there's type three.
Type three civilization. This is almost abstract. They harness the energy of their entire home galaxy.
The whole galaxy, billions of.
Stars, billions of stars, galactic overlords. Essentially, if the type three existed, it wouldn't just be detectable, the entire galaxy would look fundamentally different. Clearly managed or engineers.
In our galaxy doesn't look like that at.
All, not even close. So the clear absence of type two and type three civilizations is what really forces this rethink. If the super powerful aliens aren't there, what's left.
Which brings us back to this idea mundanity.
Right, if the extremes, extreme rarity or extreme power don't fit the observations, maybe we've been aiming too high, overestimating the technological ceiling for most life.
Okay, let's really unpack this radical mundanity that doctor Corbett proposes. This is where it gets really interesting, kind of flips the script.
The basic idea is surprisingly simple maybe the silence is explained if the galaxy just contains a modest number of technological civilizations, and crucially, their technology level is only modestly highhigher than ours, not Type two or three, maybe Type one, or just a bit past it like Type one point one exactly. Their technological ceiling is just lower than we've often assumed. They never reach the star harnessing stage.
And Corbett breaks this mundanity down into two parts, right, two dimensions.
Yes, two key aspects working together. First is technological mundanity. This is about the physical and practical limits.
So maybe etcs just don't make the breakthroughs needed for type two. Or maybe it's just too expensive or resource intensive.
Precisely, think about building a dice in sphere. The sheer amount of material, the energy investment, the logistical nightmare. Maybe it's just fundamentally beyond the reach of a civilization confined to its home planet's resources, no matter how smart they are.
So achieving Type I planetary mastery, that's achievable. It solves local problems, ensure sustainability on their world.
Right they survive, they thrive, perhaps become stable. But that leap from managing a planet's energy to managing a star's energy. Maybe that gap is just too vast.
Kind of technological cul de sac around TYPEOD.
That's a good way to put it. Maybe there are fundamental physics limitations or material science barriers, or simply the economics are astronomical and make it unfeasible. Stellar engineering stay science fiction for them, so.
Their tech would be recognizable to us in principle, clean fusion, maybe efficient interplanetary travel within their own system, advanced computing, but still planetary.
And scale exactly, still bound by the resources and energy available on one world. And the second dimension is numerical mundanity. This is about how many there are, right, The hypothesis suggests there just aren't that many etcs out there, not millions densely packed, but also not zero, just a modest number, a.
Handful, dozens, maybe scattered across the huge expanse of the galaxy.
Something like that. Enough to exist, but few enough and far enough apart that the chances of us stumbling across them or them finding us become pretty low, especially.
If they're not building giant, flashy megastructure or shouting with powerful beacons.
That's the key connection. If they're only modestly advanced and modestly numerous. We're not looking for cosmic gods beaming signals across thousands of light years. We're looking for effectively Type I planetary engineers quietly managing their infrastructure.
It changes the whole search paradigm completely.
The contrast is stark. We've been searching for galactic scale disruptions, signs of super science. Radical mundanity says we should be looking for quiet.
Competence civilizations that are successful, stable, but ultimately limited by the physics of distance and energy on a galactic scale.
They just don't have the capability or perhaps the motivation to make a huge cosmic splash.
Okay, so if we accept this premise modestly advanced, modestly numerous to the rough, what does that actually mean for their ability to, say, explore the galaxy or for us to detect them. It implies constraints absolutely.
If they're mundane, they're still fundamentally bound by physics and resource limitations, much like us. Their ability to act on a galactic scale is severely curtailed by their Type I maybe type one point one energy budget.
And these constraints are the reason.
For this silent precisely, a civilization that hasn't cracked stellar level energy, can't easily conquer or communicate across the vast interstellar voids.
Let's break down those constraints. Corvett talks about constraint one galactic conquest via robotics, even if they wanted to expand, maybe for science or survival.
The sheer scale of the galaxy is a killer app basically, even for a civilization a bit ahead of us, say type one point one or one point.
Two, sending probes out like von Neumann, probes that replicate themselves.
That's often proposed as a solution to the Fermi paradox. Why haven't self replicating probes filled the galaxy? But launching and sustaining such a program requires unbelievable amounts of energy and resources, far beyond a planetary budget.
Think about our own Voyager probes, huge effort decades later, they've barely left the Solar System in galactic.
Terms exactly, and talk about maybe sending a probe to Alpha Centauri just over four light years away, and the engineering challenges are already immense. The energy costs are huge.
Now scale that up. Trying to explore thousands, maybe millions of star systems with robotic.
Probes, the cumulative energy needed to build them, launch them, accelerate them to reasonable speeds, maybe decelerate them, ensure they work for centuries or millennia. It just likely exceeds the energy income of a planet bound civilization.
So the sheer vastness of space remains a fundamental barrier. Interstellar travel is hard even for them.
It seems plausible, yes, the logistics, the energy cost. It acts like a natural break on galactic expansion for any civilization that hasn't achieved type two power levels.
Okay, so widespread physical travel or colonization is probably out for mundane civilizations. What about communication that brings us to constraint too high powered beacons?
Yeah, this is a big one for SETI. For decades, the hope was we'd detect a deliberate, powerful signal, a beacon.
Something designed to be noticed across the galaxy shouting we are here, like the Wow signal. Maybe, though that wasn't confirmed, right.
But think about the energy needed to run such a beacon. To make it powerful enough to cross hundreds or thousands of light years and still be detectable above the background noise, I have to.
Keep it running for a long time right, millennia, millions of years. You don't know when someone might be listening exactly.
The total energy expenditure would be astronomical. We're talking about potentially diverting a significant fraction of a type by civilization's entire energy budget just to maintain this speculative shout into the void.
Would a mundane civilization see that as a sensible use of resources.
Probably not. It seems inefficient, wasteful. Even they'd likely have very efficient communication within their own solar system, focused laser beams, maybe tight microwave links, perhaps even quantum communication if they've cracked that stuff.
That doesn't spray energy wastefully across.
The galaxy exactly. So, the lack of obvious powerful beacons isn't necessarily proof no one's out there. It might just be a sign of their well, they're mundanity, their practicality. They don't have the energy to spare for galactic vanity projects.
Okay, So if they're not physically exploring widely and they're not shouting with powerful beacons, how could we possibly detect them? That leads to constraint three weak techno signatures.
This is really the crux of it for future searches. If mundane etcs exist, the only signs were likely to detect are their unintentional signals.
Their leakage radiation, like the accidental electromagnetic noise from their technology, is leaking out into.
Space precisely the hum of their civilization, Their equivalent of our old TV broadcasts, radar signals, maybe planetary defense grids, power transmission, whatever em noiser daily lives generate that isn't perfectly contained.
But you mentioned earlier, even our leakage is getting weaker, isn't it as technology gets more efficient?
It is, And that's a critical point in Corvette's argument. Are our early radio and TV was broadcast omnidirectionally, very leaky, relatively strong signals. But now we use fiber optics, which keeps the signal contained. We use focus satellite beams, low power, We're moving to spread spectrum techniques.
Laser comms all much harder to detect from light years.
Away, much harder so in etc. That's even just say a century or two ahead of us. Technologically, they've likely already transitioned to these highly efficient, very low leakage methods.
They've managed your data with incredible sophistication. Maybe using technologies we haven't even thought of yet, But the result is less accidental noise escaping.
Almost certainly, their whisper would be incredibly faint by the time it crossed interstellar distances to reach us.
So detecting that faint leakage that's a whole different ballgame compared to searching for a beacon.
Hugely different. It needs incredibly sensitive instruments, massive collecting areas, sophisticated signal processing to dig that tiny artificial noise out from the natural cosmic status. And you need to stare at individual star systems for a long time.
So the silence we hear now might not be an empty universe. It might just be the sound of our own current technological limitations. We can't hear the whispers yet.
That's the essence of the radical mundanity explanation for the silence. It's a problem of signal strength and detection threshold, not necessarily absence.
Okay, So Corbett took this principle, these constraints and use them to test the different possibilities for what the galaxy might actually look like.
Right, He set up a kind of logical framework based on those two variables. Number of civilizations many are few and their tech level high Type three or mundane Type I ish. That gives four possible scenarios.
And by applying the constraints no obvious megastructures, the difficulty of beacons, the faintness of leakage, he could basically rule out three of them exactly.
Let's walk through the eliminations. The first two are fairly straightforward, based on the lack of super science evidence. Hypothesis one many civilizations AMD very high technological level false. If there were many Type two or three civilizations, the galaxy would be obviously teeming with astro engineering projects and their heat signatures.
It isn't simple enough. What's next.
Hypothesis two very few civilizations A and D very high technological level also seems false. Even just one or two Type two civilizations, if they've been around for millions of years, should have had enough time and power to become detectable. They're waste heat, maybe probes, something should be visible somewhere. The silence argues against this too, right.
No supercivilizations, whether common or rare, so the answer must lie with mundane technology. But there are two options there.
Now it gets interesting. Hypothesis three many civilizations A and d mundane technological level. Corbett argues this one is also likely false.
Wait, why if they're mundane, they're quiet, But if there are lots of them, wouldn't the combined whispers add up. Wouldn't we eventually detect something just by sheer numbers.
That's the critical point. If there were truly many, maybe thousands or millions, scattered through the galaxy, even if each one only leaks a tiny bit of radiation, the cumulative effect becomes significant. Statistically, some should be relatively close by, close.
Enough for even their faint leakage to be detectable with our current or near future capabilities.
Plausibly, yes, over the decade SETI has been active. If the galaxy was densely populated with Type BI civilizations, we probably should have picked up some persistent, structured, artificial looking noise by now, even if it was weak. The profound lack of such signals suggests the population density isn't that high.
So the silence is just because they're individually quiet. It's also because there aren't that many of them overall.
That's the inference. The lack of any compelling signal, beacon or lukage forces us away from the many mundane scenario.
Which leaves only one possibility standing in his framework.
The last one. The conclusion that seems to best fit the observed silence if you accept the premise of mundanity, is very few civilizations with mundane technological level.
Okay, so that's the synthesis of radical mundanity. Not empty, not teeming with gods, but yeah, sparsely populated, with civilizations kind of like us, just maybe a bit further down the.
Road, exactly a modest number scattered across the vastness. They're successful, they made it past whatever filters lead to technology, but they are fundamentally constrained by planetary resources and energy. They're not cosmic architects. Their type I maybe type one point one engineers grappling with the same issues of interstellar distance and energy costs.
That we are, and that explains the silence. They lack the sheer power to make obvious signals or structures, and there aren't enough of them for their combined faint leakage to be easily detectable by us.
Yet it resolves the Fermi paradox quite elegantly, really, without needing galaxy wide catastrophes or hidden watchers it's an explanation rooted in plausible physical and economic limits.
And the big takeaway, maybe the most important part, is that it doesn't mean we're alone.
Not at all. It actually makes detection seem well, not imminent, but potentially achievable. It's just incredibly difficult. We're not looking for a foghorn, We're listening for a pin drop miles away in a noisy room.
The neighbors are home, they're just not having a loud party. They're quietly managing their household.
That's a great analogy.
Yeah, So this shift in perspective that doctor Corbett offers, it's pretty fundamental. It suggests the reason for the paradox isn't some grand, terrifying cosmic drama, but maybe just a lack of cosmic extravagance exactly.
The universe might be less like Star Wars with galaxy spanning empires, and more well just big and mostly empty, with occasional pockets of quiet, competent planet bound life. Less terrifying perhaps, but maybe more constrained.
And if this whole radical mondanity idea is on the right track, it has huge implications for how we actually do set how we search.
Absolutely massive implications. It means we should probably deprioritize searching for those super powerful obvious beacons or giant dice In's fear heat signatures. They might simply not exist in large numbers, if at all.
Instead, the focus has to shift entirely to detecting that faint incidental leakage radiation.
That becomes the prime target. The search needs to become more surgical, more patient. We need extreme sensitivity and the ability to filter out natural noise sources very effectively, and.
Corvid's study actually suggests this might be within reach.
Historically speaking, it does offer that optimistic note for perhaps the first time. He argues detecting this faint leakage might not be centuries away, but it requires the next generation of instruments.
He mentions this square kilometer array SKA specifically, right that huge radio telescope project being built now.
Yes, the SKA, or potentially the generation of telescopes that comes after it.
Why is the SKA so suited for this mundane search.
Because its design goals are exactly what's needed. It's aiming to be the most sensitive radio telescope ever constructed, with an enormous collecting area spread over huge distance.
So it can pick up incredibly faint signals.
That's the plan. Its sensitivity and processing power are being optimized precisely to pull weak structured signals like leakage radiation could be out of the cosmic background noise, even from significant distances.
It's not looking for the shout, it's listening for the whisper.
Perfectly put, the SKA is the kind of tool you'd build if you believed the radical mundanity hypothesis was correct. It matches the target. If those quiet Type II civilizations are out there, the SKA or its successors represent our best chance yet of finally hearing their faint planetary hum.
So the search gets harder in a way, needing more sensitivity, more patience, maybe more clever signal analysis, but the target itself feels more realistic, grounded in physics we actually understand.
I think that's fair to say, we just need to build much better ears and point them very carefully at the quietest places.
Okay, that leads us perfectly into a final thought for you, the listener, to chew on building directly from this idea of mundanity.
Orbit is right, and radical mundanity holds true if most etcs really do seem to stall out technologically around the type I level. What does that imply?
It suggests a kind of universal speed limit on technological growth, doesn't it?
It could? Does it mean that the real great filter isn't about getting life started or surviving nuclear war? But it's actually the monumental challenge of making that leap from planetary energy mastery type one to stellar energy mastery type two?
Is the silence simply because that jump is fundamentally too hard, or too expensive, or maybe just physically impossible for any civilization confined to a planet. Is that the barrier no one or almost no one crosses.
It's a fascinating possibility. Maybe the silence isn't philosophical. Maybe it's just engineering and economics on a cosmic scale.
So the provocative question for you is, if there's this potential technological ceiling around type I, what does that mean for us? What does our own ceiling look like? Are we already bumping up against the point where the energy and resource costs of our next big leaps true interplanetary infrastructure interstellar probes start to become fundamentally prohibitive for a planet bound species. Are we closer to our mundane limit than we think something to ponder.
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