Introduction
Four billion years of planetary history, the complete evolutionary record of life on Earth, from single-celled organisms to technological civilization. The geological transformations of a living world. The extinctions, the radiations, the slow accumulation of atmospheric oxygen. The emergence of language, art, and science.
All of it will vanish without a trace, like tears in rain.
Not through some cosmic catastrophe—though that’s inevitable too—but simply through the passage of time. Erosion, tectonic recycling, stellar evolution. Given enough time, even mountains disappear. The question isn’t whether Earth’s history will be lost. The question is whether anyone will have recorded it before it’s gone.
There’s no cosmological reason why preservation is necessary or, some might argue, even desirable. Opinions may reasonably differ on whether it should be a priority at all. But for archaeology and SETI (Search for Extra Terrestrial Intelligence) as actual research programs consuming real resources, the question must be asked explicitly: what is the ultimate objective? The answer determines everything else—methodology, funding priorities, measures of success.
The Foundational Questions
Why is archaeology pursued at all? To what end do we construct the record? For whom do we do it, and how much resources should society invest in it?
The same questions apply to SETI: to what end do we search for technosignatures (signals from technically advanced civilisations)? For whom do we conduct this search, and how should we allocate resources between detection methods, target selection, and interpretation frameworks?
These aren’t abstract philosophical questions—they’re practical ones that determine research priorities. Currently, both fields operate with implicit objectives that may not withstand scrutiny. Archaeology typically justifies itself through “cultural heritage” and historical understanding—valuable goals, but relatively weak when competing for funding against immediate social needs.
SETI traditionally frames itself as searching for contemporary communication from active civilizations—an exciting prospect, but one that becomes increasingly implausible when you account for the temporal overlap problem I discussed in my previous post.
A Logical Foundation
We can establish a more rigorous objective by starting with what we know for certain: one technological civilization exists that can understand space and time—us. We exist, we’re capable of encoding information, and we can conceive of entities separated from us by vast distances in spacetime.
From this single data point, we can reason that other such civilizations may exist in the future. They could be our own descendants after societal transformation or extinction and re-emergence. They could be entirely different lineages evolving on Earth after we’re gone. They could be civilizations arising elsewhere in the galaxy on timescales long after our extinction. We don’t know which scenario is likely, or if any will occur. But we know it’s possible, because we exist as proof of concept.
This creates a concrete objective that unifies both archaeology and SETI: if we are the first, the only, or simply the present technological civilization in our temporal window, then even if SETI finds no signals now, we can dramatically increase the probability that a future SETI project will find a record—ours.
This isn’t metaphysics. This is practical planning.
The Dual Research Program
Understanding preservation as the shared objective of archaeology and SETI creates a productive research program with two complementary branches.
First, archaeology’s meta-objective becomes clearer: we’re not just reconstructing the past for present cultural understanding. We’re establishing what kinds of information structures survive degradation across time, what encoding strategies remain interpretable despite transformation, and what patterns remain detectable despite noise. Every successful archaeological recovery is a proof-of-concept for preservation. Every failed interpretation reveals encoding strategies that don’t work across deep time.
Second, SETI should be designing temporal transmission protocols as a practical project. This serves a dual purpose: it enables us to create transmissions for future detection, and it informs what we should look for in the present. If we’re designing durable, interpretable information structures to survive millions of years, we’re simultaneously developing detection methods for finding similar structures left by others.
The two research directions inform each other. Archaeological signal processing—like the framework we published in the recent ISSC Conference Proceedings using Ireland’s archaeological data—demonstrates what kinds of patterns survive degradation and remain detectable.
These same patterns become design principles for creating future-detectable structures. Conversely, thinking about what we would create for long-term detection informs what we should be searching for in both archaeological records and astronomical observations.
Why This Matters Practically
This reframing doesn’t require accepting that preservation is cosmically important or morally necessary. It simply recognizes that if we’re already doing archaeology and SETI, we should have clear objectives that maximize the value of the resources invested.
The preservation framework provides that clarity. It gives archaeology a concrete goal beyond heritage conservation: develop and test encoding strategies that survive geological timescales. It gives SETI a concrete goal beyond listening for messages we’ll likely never receive: design transmission protocols and detection methods for signals across deep time.
And it creates a shared research agenda that leverages both fields’ expertise. Archaeologists understand how information degrades, what remains recoverable and how to reconstruct it, SETI researchers understand signal detection and pattern recognition in noise. Combined, they could develop systematic approaches to encoding Earth’s history in ways that maximize probability of future recovery.
This is the preservation imperative, and we may be living in the only window where it’s possible to act on it.
The Window Is Closing
In my previous post, I argued that archaeology and SETI are fundamentally the same discipline—signal science. If that’s true, then both fields share a common challenge: signals degrade over time, and windows of opportunity are brief.
Consider what we know about Earth’s technological window. Modern industrial civilization has existed for perhaps 200 years. Our capacity to encode and transmit information at scale—using digital systems, materials science, and signal processing—has existed for perhaps 50 years at a meaningful level. The archaeological record we’re trying to preserve spans 6,000 years of recorded history, hundreds of thousands of years of human evolution, millions of years of mammalian radiation, and billions of years of geological and biological transformation.
We’re attempting to capture and encode four billion years of history using technology that has existed for half a century. And we’re doing it while the record itself is actively being destroyed by development, climate change, erosion, and simply the passage of time.
This creates genuine urgency. We have advanced enough technology to attempt preservation—AI systems, signal processing frameworks, materials science capable of creating durable substrates. We still have an archaeological record that’s reasonably intact and interpretable. We have sufficient resources and stable enough societies to fund large-scale research programs. But these conditions are fragile.
Climate change threatens both the physical record and our capacity to study it. Mass extinction erodes the paleontological data. Urban development destroys archaeological sites faster than we can excavate them. And societal collapse—whether through climate catastrophe, nuclear war, or pandemic—could eliminate our technological capacity entirely.
If we’re in a unique window, we need to act as if it might close.
Who Receives the Transmission?
The elegant aspect of the preservation framework is that we don’t need to know who will receive the signal or when. We simply need to maximize the probability that it survives and remains interpretable across the longest possible timescales. But it’s worth considering the possible audiences, because each scenario reveals different technical requirements.
Future earthlings after civilizational collapse represent the nearest-term scenario, perhaps 100 to 10,000 years out. If our current technological civilization collapses—whether through climate change, resource depletion, nuclear war, or pandemic—survivors would need to rebuild. Having durable archives of our accumulated knowledge could prevent restarting from scratch. This scenario requires robust local storage, perhaps geological encoding or orbital repositories that survive atmospheric reentry. It’s the most tractable scenario because the audience shares our biology, our planet, and much of our context.
Distant Earth descendants operating on timescales of millions to hundreds of millions of years represent a more challenging scenario. These could be future intelligent species that evolve after we’re gone, or our own descendants so transformed by time and evolution that they’re effectively alien to us. This scenario requires extremely durable encoding—crystalline matrices, genetic insertions, or orbital megastructures that survive stellar evolution. The challenge here is interpretability: how do you create messages that remain meaningful after language, culture, and possibly even sensory modalities have completely changed?
Alien archaeologists discovering Earth after the Sun has expanded and sterilized the planet represent the deepest time scenario—billions of years. This is SETI in its purest form, but from the transmitting side. Here, the encoding must survive not just time but planetary destruction. Space-based archives, artificial structures in stable orbits, or even engineered patterns in solar system architecture become relevant. The interpretability challenge is maximal: you’re communicating with entities that share no evolutionary history, no common sensory experience, possibly no comparable physics if they evolved in radically different environments.
Our own SETI searches discovering similar preservation attempts by other civilizations could operate on any timescale, but likely fall in the range of 10,000 years to 10 million years—brief enough that technological signatures remain detectable, long enough that temporal overlap is unlikely. This scenario is particularly interesting because understanding what we would leave behind informs what we should look for when searching. If every technological civilization faces the same preservation imperative, then SETI should be searching for archives, not conversations.
Are We the Transmission?
There’s a fifth scenario worth considering, one that inverts the entire preservation framework: what if life on Earth is itself an example of temporal transmission from a previous technological civilization?
This isn’t recycled panspermia speculation. It’s a testable archaeological question. If we’re serious about temporal transmission protocols and preservation across deep time, we should apply the same investigative framework to our own origins. Archaeological SETI shouldn’t just look outward and forward—it should look inward and backward.
The timeline is suggestive. Life appears on Earth extraordinarily quickly after conditions stabilize following the Late Heavy Bombardment—perhaps within 100 million years, possibly much faster. This rapidity has always seemed remarkable. Chemical evolution from non-living to living systems is supposed to be slow, requiring vast numbers of random molecular combinations before self-replicating systems emerge. Yet it happened here almost immediately in geological terms.
The standard explanation invokes probability—given Earth’s size and the number of chemical reactions occurring, even improbable events become likely. But there’s an alternative hypothesis worth investigating: life’s rapid emergence might indicate technological origin rather than purely naturalistic chemical evolution.
If a previous technological civilization wanted to transmit information across the deepest possible timescales—spanning the death and rebirth of solar systems, surviving galactic-scale catastrophes—what would be the most durable encoding substrate? Crystalline matrices degrade. Orbital structures eventually decay. Even neutron star engravings face erosion across billions of years.
But self-replicating molecular systems that actively maintain and propagate their own information? Systems that evolve error-correction mechanisms, adapt to changing environments, and spread across planetary surfaces? That’s genuinely durable encoding. Life itself becomes the transmission medium.
Starting the Archaeological Trail: Solar Siblings
If we’re investigating this hypothesis methodologically, we should start from what we know—proper archaeological practice. Our Sun formed 4.6 billion years ago in a molecular cloud alongside hundreds or thousands of sibling stars. These solar siblings scattered across the galaxy over billions of years, but many remain identifiable through their chemical signatures and orbital trajectories.
This makes them the logical starting point for archaeological SETI. If life has technological origins involving panspermia or deliberate seeding, solar sibling systems are the most likely candidates for sharing that origin. They formed from the same material, at the same time, in the same region. If our system was seeded, theirs likely were too. If life emerged naturally here, similar conditions might have produced it there as well.
Current solar sibling searches have identified candidates like HD 162826, a star roughly 110 light-years away that almost certainly formed with our Sun. More will be identified as Gaia mission data improves stellar kinematics. These aren’t random SETI targets—they’re archaeologically motivated searches working from known relationships outward.
This is exactly how archaeology operates: start from documented connections, trace them through time, look for shared origins. Solar sibling searches become archaeological investigation across both space and time, following the trail from our Sun’s birth cloud to wherever those siblings migrated.
Investigating Technological Signatures
This hypothesis generates testable predictions. If life has technological origins, we should find evidence of engineering in its fundamental architecture. Not the kind of complexity that arises from natural selection—that’s expected regardless of origin—but signatures of deliberate design, optimization beyond what blind evolutionary processes would produce, or information encoding strategies that serve no survival function but might preserve transmittable data.
We already know some puzzling features of life’s molecular machinery. The genetic code’s error-correction properties are remarkably sophisticated. The specific amino acids used by all Earth life represent a small subset of chemically possible options, chosen with apparent optimization for certain properties. The universal use of left-handed amino acids and right-handed sugars lacks obvious naturalistic explanation.
None of this proves technological origin. But it establishes that investigating life’s origins through an archaeological SETI lens—looking for technological signatures rather than assuming purely naturalistic processes—is methodologically sound. We have one confirmed example of life. We can study its architecture in detail. We know it emerged rapidly after planetary conditions stabilized. We can identify and search our Sun’s sibling systems for related signals. These are exactly the conditions where archaeological investigation should operate.
This creates a productive symmetry in the temporal transmission framework. We’re simultaneously designing preservation strategies for future recovery while investigating whether our own existence represents successful recovery of a previous civilization’s preservation attempt. Both directions use the same methodology: signal processing applied across deep time, pattern recognition in noisy data, distinguishing technological signatures from natural processes, working from known relationships outward.
And both reinforce archaeology’s central role. Whether we’re encoding information for future discovery or decoding information from past transmission, we’re doing archaeology—recovering signals across temporal distances using physics-compatible methods.
The Funding Implication
Recognizing archaeology as informing preservation as well as reconstruction transforms its justification from cultural heritage to existential responsibility. Current archaeological funding operates on the logic of “understanding our past has educational and cultural value.”, which is true, but relatively weak when competing for limited resources.
The preservation framework makes a stronger argument: we are potentially in Earth’s unique window to encode and transmit four billion years of planetary history. If we fail to do this, that information vanishes permanently, regardless of who might have been able to use it. This reframes archaeology from “nice to know our heritage” to “species-level imperative to preserve the only known record of life’s evolution in the universe.”
This is comparable to climate science or asteroid detection—fields justified by their role in preventing existential catastrophe. If archaeological preservation is the only way to ensure Earth’s history survives beyond our technological window, then it deserves similar priority and funding.
The practical implications are significant. Every archaeological excavation becomes part of a larger dataset encoding planetary history. Every paleontological dig contributes to the evolutionary record. Every geological survey maps deep-time transformations. The question shifts from “what happened at this specific site?” to “how do we encode this information for maximum recoverability across geological timescales?”
Practical Implementation
We have the technical frameworks to begin systematic preservation now. Our IEEE paper (Foley & Furey, 2025) demonstrates one approach: treating archaeological data as degraded signals and applying signal processing methods to extract patterns despite noise, gaps, and temporal uncertainty. Working with Ireland’s Record of Monuments and Places—over 150,000 archaeological sites spanning 6,000 years—we showed that we can recover territorial boundaries, administrative centers, and invasion patterns with statistical significance, even from noisy legacy data.
But this is just the beginning. The same signal processing frameworks that extract patterns from archaeological data can inform how we encode information for future extraction. If we know what kinds of patterns survive degradation, we can deliberately create those patterns at larger scales. If we understand how temporal relationships transform into spatial geometries, we can design encoding strategies that remain interpretable despite transformation, degradation and deformation.
The research questions that emerge are concrete and testable. What materials survive millions of years in various planetary environments? How do you design redundancy levels that ensure reconstruction despite 99.9 percent data loss? What geometric and statistical patterns remain obviously artificial despite transformation over geological timescales? These are engineering problems with testable solutions.
And we have a laboratory to test them: Earth’s archaeological record. Everything we successfully recover from the past tells us something about what will be recoverable from our present.
The Responsibility
We don’t know if anyone will ever receive the transmission. We don’t know if Earth descendants, alien archaeologists, or post-collapse survivors will ever decode what we leave behind. We can’t even be certain that preservation is physically possible across the timescales involved.
But the alternative is accepting that four billion years of planetary history simply vanishes, and no one ever knows it happened. If we’re right about technological windows being brief and rare—if temporal overlap really is unlikely—then preservation becomes the only realistic goal for both archaeology and SETI.
This creates a clear imperative: use the window we have to encode as much as possible, as durably as possible, using every tool available. The archaeological sciences should receive funding commensurate with this responsibility. The theoretical frameworks should be developed urgently. The encoding strategies should be designed and tested systematically.
We might be the only civilization in billions of years of galactic history that has both the record and the capability to preserve it. That’s not just an opportunity. It’s an obligation.
If we succeed, Earth’s story survives. If we fail, it’s lost forever.
Dylan Foley
Next in This Series
This post establishes why temporal transmission protocols matter—the practical foundation for both archaeology and SETI. In the next post, I’ll examine why the 2014 call for archaeologists to contribute to SETI failed to gain traction, and how the signal processing framework bridges the paradigm gap that kept these disciplines separated.
Later in the series, I’ll walk through the technical implementation described in our recently published IEEE paper, showing how treating archaeological data as degraded signals enables pattern recovery across large timescales—and what this tells us about designing transmissions for future detection.
Related Publication: Foley, D. Furey E. (2025). “From Geospatial Patterns to Ancient Signals: A Signal Based Framework for Archaeological Machine Learning.” 2025 Irish Signals and Systems Conference (ISSC). IEEE
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