In The Beginning...
Nonfiction by Peter Jekel
Civilization begins with order, grows with liberty, and dies with chaos. Will Durant
The Earth is incredibly old. Recent estimates state that it is over 5 billion years old. To put it in perspective, imagine a 24-hour clock mirroring our planet’s history. The dinosaurs that vanished some 65 million years ago would put the time on the twenty-four-hour clock at 10:24 pm, and our arrival on the scene at 11:58:43 pm.
With that kind of enormity of time scale, who can really say whether humans are the only species to achieve intelligence and even civilization here on Earth?
Climate scientist Gavin Schmidt of the NASA Goddard Institute of Space Studies and astrophysicist Adam Frank of the University of Rochester jointly proposed a hypothesis that explores this possibility in their controversial 2018 paper entitled The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record? It gets its name from the BBC science fiction series, Dr. Who, which featured a sapient lizard people, the Silurians, whose civilization preceded our own.
Ironically, the authors indicated that they don’t really believe that there was an intelligent lizard population prior to the arrival of humans on the scene. Instead, the true purpose of their paper was to determine how it would be possible to discover signs of the impact of our present human society on the Earth. As an offshoot, though, they believed that the processes they discussed in the paper could be looked at for potential evidence of ancient civilizations on other planets or moons.
The writers, though they drew inspiration from science fiction, were surprised to find that there was very little science fiction dealing with the idea of a pre-human civilization here on Earth. Another television series, Star Trek: Voyager, touched on the topic in the episode Distant Origin. It featured a space-traveling species that, for all intents and purposes, descended from Earth’s dinosaurs.
In terms of literature, the pickings of pre-human civilization on Earth are equally weak. James Hogan used the concept in his Inherit the Stars (which the authors referenced in their article), opening with a scene in which astronauts find a human-like skull on the Moon. Toolmaker Koan by John McLoughlin involves the detection of a probe outside of the orbit of Uranus. The aliens turn out to be sapient dinosaurs. Michael Siemsen, in his novel, The Dig, follows the exploits of a man who is able to feel emotions and memories associated with objects when he touches them. At an archaeological dig in Kenya, he touches a woven metal artifact that resists traditional dating methods. As a result of his touch, the protagonist journeys back in time to make a discovery that will force humanity to rewrite its history.
Larry Niven took the idea of a pre-human civilization on Earth into a totally new territory, unlike anything out there before or since. His short story, The Green Marauder, in his collection The Draco Tavern, tells the tale of an alien that visited the Earth 700 million years ago, describing a plea from an anaerobic civilization thriving at the time, seeking help against a new environmental threat, chlorophyll. Chlorophyll is the chemical found in photosynthesizing plants and bacteria; oxygen is a waste byproduct of photosynthesis and would be toxic to anaerobes.
So, how would one determine if there was a pre-human civilization on the Earth? The archaeological record may not be enough to provide evidence since Earth is a very dynamic place. Records of previous civilizations would likely disappear over the enormous stretches of time. We think of the pyramids of Egypt as ancient, being approximately five thousand years old; however, think about the next ten, twenty, one-hundred million years from now. Do we really think they will still be enjoyed by future tour groups? The likely answer is no. The ravages of weather, water, pollution, tectonic activity, volcanism, ultraviolet radiation, crashing meteors or asteroids, all will take their toll, and they will disappear from the archaeological record.
In an imaginary future civilization, such as that found in Doris Piserchia’s A Billion Days of Earth, which takes place on Earth approximately three million years from now, rats have evolved into human-like beings. Would these intelligent rats ever be able to detect a record of our existence? Archaeologically speaking, they would likely not, but there might be a way. Instead of the archaeological record, Schmidt and Frank looked at how to detect the possibility of a civilization in the geological record.
There could be large-scale infrastructure buried under layers of sediment. Whereas concrete and metals would degrade through various processes over thousands of years, other materials would persist. Things made of stone, such as the bases of roadways and even some building foundations, could possibly be preserved from the ravages of time, leaving faint traces of their uses, though they might be so altered that their original purpose would be impossible to interpret.
Schmidt and Frank felt there had to be other ways in which our society is impacting the geology of our world that may be detectable in the distant future. Plastics, once thought to degrade fully over time, have been found not to be the case. In fact, microplastics, the end product of plastic breakdown, persist in the environment and would likely be evident in the distant future, in sediments being deposited today. Steroids and waxy lipids are another class of chemicals that would live on in the sediment for many years. In fact, they not only do not fully degrade but can even regenerate and thereby persist in the environment.
Non-naturally occurring, stable synthetic molecules such as polychlorinated biphenyls (PCBs) found in electrical devices or the pesticide dichlorodiphenyltrichloroethane (DDT) can also persist for a long time in the environment through processes called biomagnification and bioaccumulation. Biomagnification is a process whereby chemicals become more and more concentrated as they move up the food chain. First, they are consumed by microbes when they ingest the chemicals, which are, in turn, eaten by other animals, which, in turn, are eaten again by other animals, and so on. On the way up the food chain, the chemicals become increasingly concentrated. Once you reach the top of a food chain, such as, for example, an apex predator like a polar bear, the chemical will have survived in extremely high concentrations, assuming it does not reach a toxic level. When that animal metabolizes the chemical, or it dies, it is re-entered into the environment where the process begins anew. DDT and PCBs have been found all across the globe despite many bans on their use that have been in place for decades.
Our industrial society uses processes that leave other chemical indicators as well, which would be found in a future sedimentary layer. A layer of heavy metal accumulation, such as lead, cadmium, or mercury, could result from industrial pollution. Heavy metals, like many synthetic chemicals, will also undergo bioaccumulation and will not break down over time.
Though chemical signatures in the sediment are a very good indicator of a past civilization, it is not as simple as that. Natural processes such as meteor impacts or volcanism can produce chemical signatures that might mimic those of an advanced civilization.
Nuclear technology, whether used for peaceful or aggressive purposes, will leave behind radioactive isotopes that are easily detected. Some radioactive isotopes, for example, of uranium from spent nuclear fuel, have half-lives of over four billion years, almost as long as the planet has been in existence. By comparison, plutonium-244 has an even longer half-life of 80.8 million years. Unusual concentrations of radioactive isotopes in a sedimentary layer could be an indicator of past technologically advanced civilizations. That is not to say that it is automatically the result of an advanced civilization. The concept of a naturally occurring nuclear reactor was first theorized by Paul Kuroda in 1956, whereby a uranium deposit could undergo sustained nuclear chain reactions kept in check by groundwater. From theory to reality, one such natural reactor was found in Oklo, Gabon, in 1972.
A nuclear blast from the detonation of a nuclear-armed weapon could also result in not only the long-persisting radioactive isotopes being found in sediment layers, but also glassy materials created from the silica on the ground, by the extreme heat of such an event. There would also be marked alterations of the sediment layers due to the enormous explosive forces at play.
If one were to look at the planet in years past and today, there would not only be detectable chemical signatures but also mass shifts in biodiversity. For example, the Plains of the Old West, both of Canada and the United States, had a very different species profile in the early 1800s than it does today. Grizzly bears and wolves, now effectively vanished from the Plains, were common. Their main source of food was the plains bison, once numbering over 30 million animals (the wood bison subspecies, more common in the northern areas of the Canadian prairies, numbered around 170,000). In the span of less than eighty years, the population dwindled to just over five hundred animals. Only today, with enforced protected status in both countries, has the species recovered to numbers of around 200,000 to 300,000, mostly in commercial herds, with only 30,000 living in the wild. Such changes in biodiversity would impose some limitations for the extrapolation of civilized activity, as it would rely on fossils, which are relatively rare.
What about the dinosaurs? After all, we have fossils of many dinosaurs; they existed from 245 to 65 million years ago, so isn’t it possible to detect evidence of a pre-human intelligence in the fossil record? You only have to look at that timespan of 180 million years and the fact that we have approximately 11,000 dinosaur bones to have been found over the past two hundred years to realize that fossils are actually somewhat of a scarcity. If we look at the narrow timeline of the plains bison’s demise, detecting fossil evidence of their rapid decline will be like finding a needle in a haystack.
Another thing that civilizations conduct is mining, especially underground mining. Underground mining is the extraction of minerals beneath the Earth’s surface, accessing those sites through the construction of tunnels, shafts, and work chambers. The earliest evidence of mining on Earth comes to us from the ancient Egyptians, who extracted gold and copper as early as 3000 BCE. The ancient Romans took the technologies further and built very extensive underground mining operations. The Chinese were known to extract coal and precious metals from under the Earth around 2000 BCE. Pre-Columbian Indigenous societies of the New World also conducted underground mining operations in their quest for gold and turquoise. Such large-scale underground enterprises could also be detectable over the millennia.
A civilization that burns fossil fuels for energy might trigger rapid climate changes, eventually leading to its own collapse. Geological evidence of desertification, ocean acidification, or atmospheric changes could hint at such scenarios. Again, one would have to prove that the rapid climate changes were caused by technology rather than natural causes.
Agriculture also greatly impacts the planet. The seasonal nature of many crops leaves soils exposed for long periods of time, leading to increased erosion, which can be detected in the sediment through soil deposition analysis.
Environmental impacts of our civilization also trigger changes in the natural cycles of chemicals in the environment. Massive changes to the nitrogen cycle here on Earth are being altered by the heavy use of fertilizers to increase the productivity of the soil. The nitrogen cycle is a biogeochemical cycle that describes the movement of nitrogen, essential to all living things, through the various parts of our world, from the atmosphere to ecosystems to individual organisms and back again.
Another telling indicator of technological activity would be evidence of an altered carbon cycle, much due to the burning of fossil fuels. Changes in the carbon cycle are detectable by measuring the carbon isotope ratio between carbon of biological origin and that of non-biological means. Much like nitrogen, carbon, an essential element for all lifeforms, is constantly being recycled as it moves through Earth’s various systems, such as the atmosphere, the oceans, the land, and living organisms.
As with sediment deposition, we would struggle to differentiate cyclical changes and other environmental alterations as the result of intelligence or natural processes. Tectonic processes, meteor impacts, and volcanic activity could all mirror the effects of technology through a sudden rise in temperature or the destruction of an ecosystem.
In order to make the differentiation of natural versus intelligent changes in the environment, we would have to, similar to archaeological surveys today, employ a broad scope of specialties to look at not only the geology, but the chemical composition of the sediment, paleontology, archaeology, and remote sensing, among other disciplines, all to piece together a complex picture. If we looked at things in isolation, though, it would be pointless, as we know that nature is very good at mimicking us. Looking at things in a contextual manner, utilizing a multi-disciplinary approach, would be necessary to differentiate civilized activity from naturally occurring phenomena.
For example, there was an event on Earth around 55.5 million years ago, known as the Paleocene-Eocene Thermal Maximum (PETM), which spanned over 200,000 years. During this time, the Earth’s temperature rose between five and eight degrees Celsius. On the surface, it has the hallmarks of an increase in Earth’s temperature due to a civilization burning fossil fuels for energy. However, we cannot look at the evidence in isolation, as other factors are at play, causing this temperature rise. In fact, it has since been determined that the heat acceleration was due to methane release from volcanic activity.
Ironically, if humanity or any other pre-human civilization were to upgrade its technologies to become more sustainable, it would make it much more difficult to ascertain for future generations whether or not an extinct civilization existed.
Some strongly believe that indeed there has been a past non-human civilization here on Earth, one that influenced the technology and even the evolution of humanity; the purveyors were ancient astronauts from another star system. Evidence of their presence is drawn mainly from the archaeological record. The Egyptian pyramids, Stonehenge and other megalithic structures in Britain, and the giant Moai of Easter Island are all touted as being evidence of past extraterrestrial assistance. The basis of their beliefs is that it would be impossible for humanity to construct such structures without intervention by the gods. Cryptic interpretations of ancient writings, including the Bible, are also used to support their beliefs.
Though it was Harold Wilkins, a British journalist known for his writings on various pseudosciences, who in 1954 first proposed the idea of ancient astronauts impacting our early civilization, it was the Swiss writer, Erich von Däniken, who, through his controversial best-selling book, Chariots of the Gods?, truly popularized the idea. Subsequently, the idea of ancient astronauts created a whole new industry, resulting in many more books being written, films being filmed, and even field investigations to further the cause of ancient astronaut theory.
All mainstream archaeologists dismiss the claims of ancient astronaut theorists. Perhaps the biggest problem with the theory is that it underestimates the true ingenuity of the human race. Just because we cannot necessarily replicate ancient ways in modern times does not mean that humanity in the past lacked the capacity to do so. As the English writer George Herbert wrote in 1640, “where there’s a will, there’s a way.”
Today, most of us would be unable to survive the ravages of Nature’s extremes without our technology, yet many indigenous groups could do so. We only have to look at the Inuit of the Arctic as an example of that ingenuity. They survived extreme conditions, whereas we are only comfortable in the extreme north thanks to our modern technologies to move us around, keep us warm, and provide sustenance.
We could look at Greek Fire. It was an incendiary weapon used in the Byzantine Empire between the seventh and fourteenth centuries. The recipe for the “Fire” was closely guarded and could not be replicated after the fourteenth century. Most chemists today seem to agree that it is likely linked to modern napalm, a chemical developed in 1942 for the United States Chemical Warfare Service.
Despite the lack of acceptance by mainstream science, science fiction writers did not let that stop them from picking up a good theme to work with. Ancient astronauts in fictional stories actually started well before the von Daniken or even the Wilkins era.
In the nineteenth century, a number of writers touched on the subject of ancient astronauts. J. H. Rosny’s 1887 The Shapes describes sentient crystals and the encounters with Neolithic hunters of the day. Garrett Serviss’s 1898 novel, Edison’s Conquest of Mars, is likely the first tale of ancient astronauts who aided humans in the development of their great early civilizations, including many of their great monuments, such as the Giza pyramid complex and the Great Sphinx.
H. P. Lovecraft’s 1931, At the Mountains of Madness, an expedition to Antarctica finds the remains of fourteen prehistoric life forms unknown to science. Because they were found too early in Earth’s history, they could not have evolved here on Earth, but rather were aliens from another world. He also wrote the novella The Shadow Out of Time, populated by extraterrestrials known as the Great Race of Yith, who lived on Earth over 200 million years ago before being destroyed by another alien race.
Stanley Weinbaum’s short story, Valley of Dreams, describes an expedition to Mars in which they find bird-like Martians. Apparently, they had visited Earth around 15000 BCE and inspired the great Egyptian god Thoth, a deity described as having the head of an ibis and, in some cases, a baboon.
Wilson Tucker wrote The Time Masters in 1953. The story follows the exploits of a private detective who turns out, as the story moves along, to be none other than the Mesopotamian hero Gilgamesh of the epic poem Epic of Gilgamesh. It is not certain, but it is possible that the inspiration for Gilgamesh came from a true king of Uruk, a Sumerian city-state around 2900 to 2350 BCE.
The Blue Planet, written by Carlos Rasch in 1963, describes ancient astronauts as having landed on Earth around 5000 years ago in ancient Mesopotamia. The astronauts find themselves with somewhat of a quandary. They are greeted and worshipped by the people of Earth as gods, not the intent of their visit at all.
The famous Known Space series by Larry Niven (it began in 1964 and continues to this day) describes the human race as being descended from aliens called the Pak. In the 1973 novel of the series, Protector, the reader discovers that Pak children are found in Earth’s fossil record as our human ancestor, Homo habilis.
The Day the Gods Died, by Walter Ernsting, fits right in with the ancient astronaut theories. In the story, extraterrestrials were responsible for the building of the ancient civilization of Peru.
William Keith Jr. wrote the Heritage Trilogy, which described a war between the United States and Europe, and later in the series, between the United States and China. The roots of the conflict lie not in what one might expect, but rather in the knowledge that humanity’s evolution may have been directed by ancient aliens.
Perhaps the most interesting of the ancient astronaut stories is one that is not so ancient but rather medieval: Michael Flynn’s Eifelheim. In 1349, during the Black Death in Europe, a small town, Eifelheim, in the Black Forest of Germany is visited by a group of aliens who had crashed in the nearby woodland. The story essentially follows the interaction between the Town’s priest, Father Dietrich, and a technologically advanced group of aliens, making for an interesting juxtaposition of superior technology and firm theological beliefs.
Perhaps the most powerful image of ancient astronauts interfering with humanity’s evolution comes from Arthur C. Clarke’s 1953 short story Encounter in the Dawn, which was expanded to serve as the introduction of the novel 2001: A Space Odyssey. The imagery of the monolith found on Earth by human primate ancestors from both the novel and its classic Kubrick movie still resonates for readers and viewers to this day.
So, with difficulty, we can perhaps see traces of a pre-human civilization here on Earth. Did they actually exist? Can we apply the ideas from the paper by Schmidt and Frank to other worlds we might one day explore?
After all, our universe is ominously silent. Despite years of listening to the heavens through various SETI programs, we have not detected any signal that could be construed as intelligent. We have the WOW signal found on August 15, 1977, that could have been evidence of an intelligent signal, but we have never heard a repeat to date.
Perhaps we have to come face-to-face with the Fermi Paradox. The paradox was hypothesized by one of the physicists involved in the Manhattan Project, Enrico Fermi, who questioned if there is intelligent life out there, where are they? There should have been evidence by now. The Fermi Paradox has many hypothetical solutions, including the idea that we are the only intelligent life in the universe; based on probability alone, that would seem unlikely. There is the possibility that intelligence will always evolve to a point of self-destruction. Then again, given that the age of the Universe has been estimated to be between 13 and 14 billion years old, it is entirely possible that there have been many civilizations in the Universe, but that they are now long gone. How would we be able to detect a civilization in an ancient world that went extinct billions of years ago? Certainly, the archaeological record would be sparse at best or non-existent, but putting to work a multidisciplinary study of a world could yield results that might strengthen the case for a past civilization. We don’t even have to venture to the stars to do so. The pasts of both Venus and Mars were likely far more conducive to life in their ancient pasts.
The paper by Schmidt and Frank was meant to be a thought experiment, and though the authors were very clear in their doubt of the existence of past civilizations here on Earth, there is also an old statement made by Carl Sagan that would be very fitting. “Absence of evidence is not evidence of absence.”
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