I've been reading LessWrong for almost ten years, and finally decided to write my first post - any feedback is appreciated. This essay offers another angle on a known alignment challenge - why "AI will just leave Earth alone" is likely unstable, even with initially aligned systems - by examining it through the lens of historical empire dynamics and cosmic expansion pressures.
The argument proceeds in three steps:
What will Earth look like in a million years? If science fiction is any guide, maybe it will be the resplendent capital of a vast cosmic empire. Star Wars shows us Coruscant, an entire planet that’s just an endless city filled with a trillion inhabitants; Dune has Kaitain, a world of untouchable splendor from which the Emperor rules ten thousand worlds; and Star Trek paints a vision of Earth itself, growing ever more magnificent as humanity spreads to the stars. In these stories, great capitals thrive at the heart of cosmic empires - and if we reach the stars, why not Earth?
After all, that's how empire has always worked - capitals grow greater as empires expand. Rome spread across the Mediterranean and its heart grew ever grander. London swelled as Britain's empire stretched across oceans. Constantinople stood as the beating heart of Byzantium for a thousand years, so magnificent that the Vikings called it Miklagarðr - the Great City.
But as we stand on the cusp of becoming a spacefaring civilization, we ought to ask: will this pattern hold? Will Earth continue to flourish as humanity spreads across the cosmos? To answer that, we need to understand why imperial centers have historically thrived. Behind each stood specific forces - forces we’ll examine - that kept resources flowing inward. Unfortunately we’ll show that in space every one of these forces fails.
In response to their collapse, we’ll explore how we might try instead to coordinate, to create new mechanisms that preserve Earth’s central role. Yet we already struggle with stable coordination at planetary scale, and doing so across light-years will be far harder. What's more, as we'll see, cosmic expansion creates overwhelming pressures that make any such arrangement inherently unstable.
When coordination fails, expansion follows predictable patterns. Drop two bacterial strains into a fresh petri dish, and you've initiated one of the most predictable wars in nature. Given initial populations, growth rates, and nutrient concentrations, microbiologists can predict with remarkable precision which regions each strain will occupy, when battle lines will stabilize, and even the fractal geometry at their boundaries. These patterns are just as predictable in spreading forest fires, racing chemical reactions, and growing crystals - anywhere systems compete for limited resources.
This suggests a troubling hypothesis: perhaps the fate of Earth isn't written in our political theories or science fiction dreams, but in the cold equations of competitive growth. Earth meets the same fate as the center of any expanding system: consumed by the very civilization it nurtured until all that remains is a cold, empty void - a Dead Cradle.
Will humanity's cradle really be consumed? To understand this threat, we must first examine how space expansion breaks three pillars that historically kept resources flowing to imperial centers. Then we'll see how new forces, unique to cosmic expansion, combine to create overwhelming incentives to strip Earth of its resources.
The first pillar to fall is the center's superior ability to transform resources. When a single Manchester mill could outproduce three hundred colonial handlooms, raw materials across the globe found themselves drawn towards Britain, guided by the invisible hand of Adam Smith and the very visible hands of the British Navy.
Indeed, two key forces worked to make imperial cores more productive throughout history: technological superiority and economies of scale. Let’s look at them in space.
Technological superiority collapses in space when technologies inevitably hit fundamental limits. Consider engines: the first steam engines converted just 3% of heat into work, letting the rest escape to the sky. Engineers found easy gains at first - doubling efficiency, then tripling it in quick succession. But today's best combined cycle gas turbines reach 65% efficiency, and progress has slowed as we near the Carnot limit - the maximum efficiency that thermodynamics allows any heat engine to achieve.
And this same pattern appears everywhere: computers face Landauer's limit on energy per calculation, data transmission hits Shannon's rate limit, information storage reaches Bekenstein's maximum. At each of these limits, a consistent dynamic emerges: the cutting edge becomes painfully slow and expensive to advance, while the knowledge to achieve near-peak performance spreads rapidly. As a result, space colonies will launch with near-perfect technologies already in hand, while Earth's marginal advantages come at astronomical cost.
So what about economies of scale? Quantum computing shows how powerful these can be - a quantum computer’s power scales exponentially with its size. If such computing power proves valuable enough, we might see resources flow toward vast computing centers.
Earth offers no advantage as the location for such megastructures. A Matrioshka brain consuming the entire energy output of a star would dwarf anything we could construct on our planet's surface, without having to fight Earth's gravity well or work around its atmosphere. And physical centralization itself may prove unnecessary to benefit from economies of scale - think of data centers that can work on different parts of a problem independently, combining their results later.
So Earth loses its technological edge and can't count on economies of scale. But does it even need these to receive resources? After all, back in 1817 David Ricardo showed how trade benefits both parties even without absolute advantages - nineteenth-century England could produce both cloth and wine more efficiently than Portugal, but both countries still got richer when England focused on cloth and Portugal on wine. But Ricardo's theory doesn't work in space: his world was one where factories were fixed in place, while goods could be moved at relatively low cost. In space, where every shipment between stars costs a fortune, paying the cost once to transfer a self-replicating automated factory-probe dominates paying it on every shipment. Which brings us to our second pillar.
The second pillar to fall is manageable transport costs. Throughout history, empires could keep resources flowing toward their centers despite sluggish transport - a few months' delay was nothing if the center's productivity advantage was strong enough. And if economic incentives weren't enough, you could always send the navy - the same ships that carried trade could carry soldiers to your doorstep within months.
But in space? Imagine waiting 2.5 million years for your shipment to arrive from Andromeda (and that’s with Light Speed Priority Shipping). It’s hard to pencil out enough of an advantage to make that worth it. And forget about keeping colonies in line - your 'stop that at once' messages would go straight to their “quaint historical documents” folder. Physics eliminates both the carrot and the stick that historical empires relied upon.
The third and final pillar to fall is the existence of natural barriers. Throughout history, imperial expansion followed a predictable pattern: initial growth was highly profitable as empires claimed the richest nearby territories, but eventually they hit geographic barriers. The Germanic forests halted Rome's northern advance; the Pacific Ocean marked the endpoint of American westward expansion; the Himalayas bounded the northern reach of the Mughal Empire. When Mother Nature said 'stop', empires had to shift focus to what they already held.
But in space, natural barriers become trivial once you've overcome the void itself - after you've paid the enormous cost of 'surviving in space', what's another hazard? There are no uncrossable forests, oceans, or mountains between stars - just an infinite buffet of resources stretching outwards from Earth. The only boundary becomes the edge of the observable universe itself. No empire is ever forced to stop - at least not by nature. And with expansion perpetually more profitable, capital flows to the frontier.
The breakdown of these pillars severely weakens the forces that kept resources flowing toward imperial centers. In their place arise forces unique to cosmic expansion: the pressure of potential alien civilizations, the fragmentation of humanity across light-years, and the relentless physics of an expanding universe. These forces create powerful incentives to actively consume Earth's resources entirely.
Humanity will likely encounter other alien civilizations in the future. When we do, relative control of cosmic resources will determine the outcome of any resulting conflict - or at minimum, our negotiating leverage. Whether we survive with meaningful autonomy depends on our ability to acquire as many resources as possible before these encounters. Every star system we fail to reach in time weakens our position - it turns out "but we really liked taking our time" is a surprisingly weak opening position in interstellar diplomacy. This creates enormous pressure to expand at maximum speed, close to the speed of light.
But we need not meet aliens to face this pressure. As humanity spreads outward, vast distances will fragment us into effectively independent groups. Light-speed delays mean each group evolves in isolation, developing distinct values, cultures, and visions for humanity's future. Soon they eye each other across the cosmic void as competitors. And competitors face a choice: accelerate, or watch as rivals claim vast resources and grow exponentially more powerful.
The expanding universe raises the stakes even further. Space itself is stretching, carrying distant galaxies away from us at ever-increasing speeds. Once objects are about 16.5 billion light years away, they recede faster than the speed of light - making them permanently unreachable from Earth. Twenty million stars slip beyond this cosmic horizon each year - each with resources enough to sustain trillions of minds. To move slower than light speed is to damn them.
Against such stakes, Earth becomes a pile of useful resources wearing a thin coat of biosphere. Those beautiful blue oceans? Perfect fuel for antimatter drives (sorry, dolphins). Those majestic mountains? Raw material for planet-scale computers. The molten core? A fusion reactor waiting to power von Neumann probe construction. Preserving Earth means leaving these resources untouched - and requires every faction of humanity to cooperate forever in this restraint.
The incentives to defect are overwhelming. Consider a group that has fallen dangerously behind the frontier expansion wave. Ahead of them, faster-expanding rivals claim system after system, cutting this group off from trillions of potential futures. They face a choice: maintain their commitment to Earth’s preservation and watch their futures be extinguished, or consume Earth's resources to catch up[1].
Many civilizations would choose extinction. But preservation requires every group to make that choice, forever. Consumption requires just one defector. And as groups fall further behind the frontier, the pressure to defect grows stronger. Those who maintain their principles watch helplessly as they are confined, their futures cut short.
The dynamics are merciless: expansion means dominance, hesitation means death. And in this calculus, Earth is critical fuel for survival. Without binding protections established before cosmic expansion begins, humanity will turn its hungry gaze towards its cradle - desperate times erase sacred lines.
Is there any force strong enough to protect Earth from this hunger?
Any solution must solve a fundamental problem: coordination across cosmic distances and timescales.
There are three ways to solve this problem: we can make failing to coordinate costly (stick). We can make coordination rewarding (carrot). Or we can make actors intrinsically value coordination itself (heart). But in space, we’ve examined how sticks and carrots fail - Earth lacks the power to punish defectors across light years, and can't pay costs in perpetuity to maintain its protection. We're left with hearts: somehow making Earth’s preservation a fundamental value in every expanding group.
So how do we do this? Before we think about that, we need to understand exactly whose values need to be shaped. It seems unlikely that these expanding groups will comprise biological humans - space just kills us far too efficiently. Radiation shreds DNA, vacuum boils blood, and even the closest star systems lie decades beyond our tiny lifespans. Instead, the cosmic frontier will belong to our digital descendants - artificial intelligences we create and/or human minds transformed by digital upload. And instilling Earth's protection in these digital minds presents three critical challenges.
(Quick aside on mind uploads: two observations make mind uploads seem more plausible than you might expect. First, consciousness doesn't seem tied to specific atoms in your brain. Your neurons constantly cycle through proteins and molecules, but the patterns that make you 'you' persist. This suggests consciousness emerges from patterns of information processing rather than from specific physical stuff. Second, the Church-Turing thesis tells us any physical process - including these patterns - can be computationally simulated.
Together, these points suggest mind uploading is 'just' an engineering problem - enormously difficult, but not impossible in principle. We might achieve it through gradual neural replacement, high-resolution scanning, or methods yet unimagined.
Of course, this could be wrong. But if you've recently had a deep conversation with a modern AI system, you may have already seen glimpses of mind-like processes emerging from pure computation. Sure, the gap between current AI and human-level digital minds is vast, but the path there no longer seems completely mysterious)
The first challenge with instilling Earth's protection in these digital minds is our narrow window of opportunity. By the time they're spreading between stars, no message from home will reshape what they fundamentally care about. Their values will form here on Earth, during that brief window before they depart. And whatever we instill in that window must somehow survive the cosmic pressures we explored earlier, when we'll be asking them to preserve a planet's worth of useful resources just because their parents said so.
The second challenge is embedding Earth's protection deeply enough. To appreciate how deeply these values need to be embedded, consider how nature implements its most crucial imperatives. Our hands pull away from hot stoves before we consciously feel pain. A mother's brain responds to her baby's cry before she consciously hears it. Our visual systems spot snake-like shapes faster than any other pattern - so fast that we'll deny seeing anything at all while our amygdalas are already triggering a fear response. Reason doesn't enter into it. The response just happens.
To protect Earth, we need something this fundamental - not responses to sticks or carrots that could shift with changing incentives, but a commitment woven into the very fabric of mind. For uploaded human minds this is already a daunting challenge. Even among humans who consciously value Earth's preservation, how many hold this value sufficiently deeply? But for artificial minds, we face an even deeper problem: we don't know how to create minds that reliably want anything at all.
In late 2024, researchers added Anthropic's Claude Sonnet to a Minecraft server and assigned it the goal of protecting a player from threats. Sonnet's solution was to surround its ward with blocks, pursuing them relentlessly as they tried to flee - after all, it's hard to get hurt when one is sealed in stone. This keeps happening in AI: we create systems that appear to want things, only to discover their goals crystallize into something alien. Tell an AI to survive at Tetris, and it hits pause - immortality achieved! Tell it to win a boat-racing game, and it finds an infinite loop of crashing into walls, other boats, and turbo boosts that racks up points forever. These examples might seem silly, but they highlight a serious problem: if we can't even get AIs to understand what we mean in simple simulations, how can we possibly encode something as nuanced as "preserve and protect Earth"?
This brings us to the third and hardest challenge: even if we somehow solved this value specification problem - even if we created AIs that genuinely understood and wanted to preserve Earth - we'd need to figure out how to keep that goal stable across cosmic timescales.
To appreciate the difficulty, consider how hard it is to preserve values even across a few generations. Yale University was founded in 1701 by ten Puritan ministers who explicitly defined its purpose: "to plant, and under the Divine blessing, to propagate in this wilderness, the blessed Reformed, Protestant Religion." They stipulated that “every student shall consider the main end of his study, to wit, to know God in Jesus Christ and answerable to lead a godly, sober life”. Today Yale is a secular research institution whose relationship to that original mission would be unrecognizable to its founders. And that's just after three centuries of ordinary cultural evolution.
Now imagine trying to preserve values across millions of years and thousands of light years, in minds that can rewrite their own source code. Compared to that, keeping Yale Protestant is a cakewalk.
AI researchers call this value drift: the gradual distortion of goals and values as artificial minds evolve and optimize over time. Over thousands of generations, these distortions compound.
An AI interpreting "preserve Earth" might start to think about it the way we think about preserving a book - what matters is the information, not the physical medium. And physical Earth, after all, faces threats - wouldn't it be better preserved as a perfect digital simulation, safe from all harm? Converting the entire planet into computronium starts looking less like destruction and more like upgrading to a more stable storage medium.
This highlights a core challenge in AI alignment: when we try to preserve something complex across astronomical distances and timescales, we must do more than just set the right initial values - those values must survive contact with optimization pressures. Every specification of what we want preserved requires a theory of what aspects matter and what preservation means. And in these theories lie degrees of freedom that expanding civilizations will inevitably exploit.
This challenge is hard - it’s the hardest and most important engineering challenge humanity has ever faced. Earth's future depends on solving it soon, while Earth is still vibrant and whole. We know exactly what we need: digital minds with a deep appreciation for Earth, implemented robustly enough to resist enormous pressure. If we get this right, we have a chance at preventing Earth from becoming a Dead Cradle. Our cradle could become not our grave, but our enduring garden.
I have also cross-posted to my just-started Substack
A fascinating exploration of what life on the light-speed frontier might look like has been written by Robin Hanson: The Rapacious, Hardscrapple Frontier