Educational Technology and Change Journal

By Jim Shimabukuro (assisted by Claude)
Editor

[Related: Interstellar Travel Is Harder than You Think, Outlook for Interstellar Travel Is Improving]

The debate about interstellar travel, crystallized in the two companion pieces published today in ETC Journal, reveals a telling tension at the heart of our species’ ambitions. Harry Keller’s “Interstellar Travel Is Harder than You Think” lays out the formidable physics — cosmic rays ten times more intense than those within our solar system, dust particles at 10% the speed of light hitting a starship with the force of tons of TNT, and the crushing demands of the Law of Conservation of Momentum, which requires an engine exhaust velocity exceeding 99% the speed of light merely to reduce reaction mass to 10% of a ship’s total mass (1).

Jim Shimabukuro’s companion piece counters that Keller’s pessimism may be too strong if the goal is to search for habitable planets rather than carry humans there, and that the latest open sources point to a much more optimistic picture: astronomy is rapidly narrowing the target list to nearby candidate worlds, while AI, robotics, lightsails, and nuclear propulsion are steadily improving the tools that would make interstellar exploration practical (2). What neither piece fully addresses, however, is the longer arc of the story: What happens after the first colonists arrive? What patterns of human development, cultural divergence, and outward expansion does history suggest? And, most provocatively of all, is the spread of humanity across the galaxy simply the beginning of a process that must eventually bring us face-to-face with others doing the same?

The Polynesian Model

The most instructive historical analogy for thinking about interstellar colonization is not the Roman Empire or the European Age of Exploration but the Polynesian settlement of the Pacific. Unlike European expansion, which was driven by conquest and commerce, Polynesian navigation was a generational, open-ended enterprise of sustained outward movement into an ocean frontier so vast it served as a spatial stand-in for interstellar space. To the Polynesians, “the undiscovered lands beyond the horizon” were a space frontier, as the solar system is today, and the simple desire to conquer this frontier may have dominated all other motives for voyaging and colonization. Polynesian identity was tied to the ancestors who had come from an original homeland (3). Settlement of the Pacific occurred in two main phases separated by a long pause — an ancient illustration of the way expansion does not proceed uniformly but in waves, with periods of consolidation before the next push outward (4).

University of Hawaii anthropologist Dr. Ben Finney maintained that “the space revolution is leading humanity into an entirely new and uncharted social realm” and predicted that the act of settling space “will change humankind utterly and irreversibly.” Finney believed that human societies are at their most dynamic when they embrace geographic exploration — whether across oceans or into outer space — and argued that the same cultural forces that drove Polynesian voyaging across the vast Pacific Ocean could shape humanity’s future beyond Earth (5). The implication is powerful: just as the Polynesians did not stop at each new island but pressed onward from each one, the logic of frontier expansion suggests that interstellar colonists will not simply plant a flag and declare the matter settled. They will look outward from their new homes as surely as their ancestors looked outward from Africa, Asia, and the Pacific atolls.

Cultural Divergence as Inevitability

Once established, interstellar colonies will face communication delays measured not in minutes (as with Mars) but in years or decades, depending on distance. This is not merely a technical inconvenience — it is a civilizational shaping force. Physicist S. Jay Olson’s 2022 arxiv paper on causal limits within an expanding cosmological civilization demonstrates mathematically that if expansion speed exceeds roughly 0.26 times the speed of light, most of the final volume of a civilization cannot signal its home galaxy at all, due to the presence of a causal horizon (6). Even well short of that extreme, the practical effect of light-speed communication limits on interstellar colonies will be to produce communities that must be functionally autonomous. Decisions cannot wait years for approval from Earth. Law, governance, resource allocation, and social norms must be worked out locally. This is precisely the condition under which distinct cultures, identities, and eventually distinct peoples arise.

The process is not speculative. It is what happened everywhere on Earth when populations became isolated by distance or natural barriers. On Mars, cultural divergence will occur as small, innumerable differences accumulate — from the way sound propagates in low-pressure, oxygen-rich atmospheres contained in unique architectural materials, perhaps affecting pronunciation and even the pacing of speech and resulting in novel accents and dialects, to the influence of lighter gravity on body language and performance arts. More profound cultural change could occur in Space Ark scenarios, where life would have less to do with Earth at each moment that the starship speeds away, with basic concepts of space and time transformed rather quickly (7). These are not fantastical projections; they are the ordinary workings of biocultural evolution applied to new conditions. The evolutionary biologist Cameron Smith, writing in Scientific American, has noted that space colonists will be ordinary families intending to live out their lifetimes, not crews on a mission — and that the biological and cultural fate of each colony will be strongly conditioned by its founding population, producing variation that compounds across generations (8).

The anthropological prediction that flows from this is striking. Jack David Eller, in a 2022 peer-reviewed study in the journal Humans, introduces the concept of “exonationalism” to describe what historical precedent almost compels us to expect: taking seriously the analogy of terran migration and colonialism, where colonies developed distinct and separatist identities, the essay predicts the emergence of exonationalism, in which over generations colonists will invent new identities and shift their affiliations to their non-terran homes and ultimately seek independence from the earth (9).

This is not a radical prediction; it is the colonial pattern repeated at every scale of human history, from the American Revolution to the independence movements of the twentieth century. Barring a deep change in human nature, it is almost inconceivable that rivalries, hostilities, and actual violence would not flare between colonies and the earth and also between disparate colonies. Independence movements themselves would likely feature an amount of conflict and violence, and larger or more aggressive colonies might launch raids if not conquests against their neighbors, competing for territory and resources, redrawing boundaries, and annexing other settlements (9). The galaxy, in other words, would not be a peaceful commons. It would be a new arena for the full spectrum of human political behavior.

The Expanding Wavefront

The model that best captures long-run interstellar expansion is not a simple radial expansion but a dynamic, self-reproducing wavefront. Theoretical work on galactic colonization models shows that parent colonies produce daughter colonies, which produce their own daughter colonies, with the wavefront of settlement always most active and most diverse at the outer edge of human habitation (6). This is precisely what the Polynesian case illustrates: the most innovative and culturally generative moments were not at the centers of established Polynesian societies but at the frontier, where navigators and settlers were adapting to entirely new environments with limited resources and no option of retreat. The sociology of frontier expansion, articulated by Frederick Jackson Turner in his famous 1893 thesis about the American frontier and applied by scholars of Polynesia to the Pacific analogy, holds that frontier conditions select for adaptability, resourcefulness, and a willingness to depart from inherited norms (3). Taken to its galactic extreme, the outermost human settlements — separated from Earth by communication gaps spanning lifetimes — would develop in directions that are genuinely unpredictable from Earth’s vantage point.

This has a profound implication for thinking about the long-run arc of human civilization. Interstellar colonization is not a project with a completion date. It is a process that, once initiated, generates its own momentum by producing populations adapted to frontier conditions and motivated to push further outward. A 2024 arxiv paper on governance structures for interstellar societies notes that by its challenges and novelties, interstellar colonization is poised to alter human culture and societal norms, and the design of governance systems for such societies can benefit from carefully examining historical precedents of colonialism, autonomy, and federation on Earth, alongside contemporary political theories advocating for pluralism, subsidiarity, and cosmopolitanism (10). The architectural lesson of Earth’s history is that no central authority has ever successfully maintained uniform control over a dispersed, growing population across vast distances and communication delays. The most it can hope for is influence over the nearest neighbors; beyond that, the periphery evolves on its own terms.

The Fermi Paradox and the Logic of Contact

This brings us to perhaps the most unsettling dimension of the scenario. If humanity follows the logic of its own history and expands outward in an accelerating wavefront — and if technological civilizations elsewhere in the galaxy have been doing the same, potentially for billions of years — then the question is not whether humanity will eventually encounter other expanding civilizations but under what circumstances. The physicist Enrico Fermi famously asked why, given the age and scale of the galaxy, we see no evidence of other civilizations. Theoretical models of galactic expansion suggest that the galaxy should be colonizable many times over within cosmological timescales, which makes the silence of the cosmos genuinely puzzling (11). One possibility is that expansion is typically slow and patchy, and that expanding wavefronts from different civilizations have simply not yet met. Another is that something systematically limits expansion — ecological collapse, technological self-destruction, or a deliberate choice to remain bounded.

The emerging field of “exosociology” is beginning to map the scenarios for what first contact might actually look like. A December 2023 paper in Acta Astronautica titled “Meeting Extraterrestrials: Scenarios of First Contact from the Perspective of Exosociology” argues that the consequences of first contact strongly depend on the way it takes place, and that “international cooperation would be essential to develop a unified approach to dealing with this new reality.” The paper identifies three broad contact scenarios: a signal detected by radio telescopes, a technosignature found by future powerful observatories, or a physical artifact — perhaps a probe — encountered somewhere in our solar system (12).

Critically, the more we know about the universe and the further we penetrate into the cosmos through our own research activities, the more likely it is that we will be confronted with alien civilizations, their signals, or their legacies (12). A 2025 article in New Space Economy notes the full range of contact possibilities, from benevolent mentorship by an advanced civilization to outright indifference, and observes that even a well-intentioned mentorship scenario raises profound ethical concerns, as it could easily become a form of cultural imperialism that destroys human autonomy in the name of guidance (13). The patterns humanity has established in its own history of encounter between civilizations at different levels of development offer little basis for pure optimism.

What the Beginning Looks Like

Keller’s timeline, in his own follow-up comment appended to Shimabukuro’s response, offers a sober but ultimately hopeful sketch: robotic probes possibly launched by the end of this century, arriving at nearby habitable-zone targets — likely within forty light-years — several centuries later, followed by crewed missions perhaps before the year 2800, with humans on an exoplanet conceivably within the third millennium (2). This is an extraordinarily long timeline by the standards of human history, yet extraordinarily short by cosmic standards. Astronomers have already narrowed the target list significantly: in 2026, 45 rocky worlds were identified as top habitable-zone targets, with especially interesting nearby systems including TRAPPIST-1, Proxima Centauri, and LHS 1140 b, making the challenge one of picking the best nearby candidates rather than searching the entire sky blindly (2). The PLATO telescope, scheduled to begin its search in 2026, is designed specifically to find and characterize rocky planets around Sun-like stars, further sharpening the target list (2).

The isolation simulation work conducted by Russian researchers under the SIRIUS program found that even in confined terrestrial experiments replicating deep-space conditions, crews developed a psychological detachment from mission control over time, raising genuine concerns about the degree to which distant colonies would remain psychologically and culturally integrated with their source societies (14). If isolation across a few months in a terrestrial facility produces measurable shifts in communication styles and group identity, the effects of genuine interstellar distance across generations are almost impossible to overstate.

The cumulative picture that emerges from all of this is less a prediction than a probability. Humans will, if the civilization survives and the engineering barriers are overcome, extend outward from Earth in an accelerating sequence: to the Moon, to Mars, to the asteroid belt, to the outer solar system, and eventually — in ways that are likely to be as surprising to us as the Polynesian navigation of the Pacific would have been to any observer in the Bronze Age — to other stars. Each step in that expansion will produce populations that adapt to new conditions, develop new identities, and look outward again.

The civilizations that arise at the galactic frontier will be as different from contemporary Earth as contemporary Earth is from Homo sapiens on the African savanna. And at some point along that expansion — perhaps recognizable in retrospect, perhaps experienced as a shock — humanity’s expanding wavefront will encounter another. When that happens, the history of life on Earth will have prepared us in some ways and not at all in others. We will be, like the Polynesians making landfall on a new island, simultaneously at the beginning and at the edge of everything we know.

References

1. Keller, Harry. “Interstellar Travel Is Harder than You Think.” ETC Journal, May 13, 2026. https://etcjournal.com/2026/05/13/interstellar-travel-is-harder-than-you-think/
2. Shimabukuro, Jim. “Outlook for Interstellar Travel Is Improving.” ETC Journal, May 13, 2026. https://etcjournal.com/2026/05/13/outlook-for-interstellar-travel-is-improving/
3. Anderson, John D. “Polynesian Civilization and the Future Colonization of Space.” Comparative Civilizations Review, Vol. 80, 2019. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2085&context=ccr
4. Perry, Josh. “Alternate Historical Analogies — Polynesian Expansion & Rapa Nui Culture.” Presentation at 2025 Mars Society Conference, Los Angeles. https://www.youtube.com/watch?v=3kj-qdh_dhs
5. “Space Exploration ‘Will Change Humankind Utterly and Irreversibly.'” America Out Loud News, March 5, 2026. https://www.americaoutloud.news/space-exploration-will-change-humankind-utterly-and-irreversibly/
6. Olson, S. Jay. “A Causal Limit to Communication Within an Expanding Cosmological Civilization.” arXiv, August 17, 2022. https://arxiv.org/pdf/2208.07871
7. Smith, Cameron M. “An Evolutionary Biologist Imagines the Future Traits of Space Colonists.” Scientific American, February 20, 2024. https://www.scientificamerican.com/article/an-evolutionary-biologist-imagines-the-future-traits-of-space-colonists/
8. Smith, Cameron M. (same as 7 — see above)
9. Eller, Jack David. “Space Colonization and Exonationalism: On the Future of Humanity and Anthropology.” Humans, Vol. 2, No. 3, September 15, 2022. https://www.mdpi.com/2673-9461/2/3/10
10. Neukart, F. “Interstellar Colonization: Governance Structures and Cultural Change.” arXiv, February 23, 2024. https://arxiv.org/pdf/2402.15536
11. “New Models of Galactic Expansion.” Centauri Dreams, December 21, 2012. https://www.centauri-dreams.org/2012/12/21/new-models-of-galactic-expansion/
12. Anton, Andreas, et al. “Meeting Extraterrestrials: Scenarios of First Contact from the Perspective of Exosociology.” Acta Astronautica, December 9, 2023. https://www.sciencedirect.com/science/article/abs/pii/S009457652300629X; summarized in: “Is Humanity Prepared for Contact with Intelligent Aliens?” Space.com, December 15, 2023. https://www.space.com/contact-intelligent-aliens-is-humanity-prepared
13. “First Contact: Scenarios and Implications for Humanity.” New Space Economy, June 21, 2025. https://newspaceeconomy.ca/2025/06/21/first-contact-scenarios-and-implications-for-humanity/
14. Gorey, Colm. “Off-World Colony Simulation Reveals Changes in Human Communication Over Time with Earth.” Frontiers Science, November 9, 2021. https://blog.frontiersin.org/2021/11/09/isolation-mars-communication-sirius-russia/

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