Small, Old Civilizations

Since there are no signatures, at least bold, obvious ones, that there was a large, ancient civilization before our era, the possibility of a small, ancient civilization needs to be examined. When we say small, we mean one which stays below some fixed population count. The population limit is small compared to modern populations, or even ones of a century or two ago. The number might be tens of thousands or hundreds of thousands of people.

Why would a civilization keep its numbers down, especially in early eras when the concept of resource exhaustion would not have been known? What motivations could there be for limiting a population? Civilizations, especially early ones, are led by some individual, or in rare cases a small group. So the question really is, why would a leader take actions to limit the population of the people he governed? The usual case, in our history, is that leaders never do such things. Perhaps they might be forced to.

Suppose a tribe lived in a river valley, and a chieftain long before had established a belief system which included the rule that anyone emigrating from the river valley was insulting the chief and betraying his tribe. It would be easy to have this incorporated into the theology that was around at the time, as theology has the knack of adapting to rulers' desires, although not in an obvious manner. So, if this one chieftain had felt insulted and started this tradition, the population outside of the river valley would stay at zero. Perhaps the tradition includes any secretive emigrants being hunted down. With this rule in place, there is no possibility other than a limit to total population.

A river valley such as the one in this example would have a certain amount of water flow, from the river and from rain, and that might be the limiting factor in how much food could be grown. Some years might be better than others, but when a bad year came, or a stretch of drought years, the limit would be unstretchable. After some decades or even centuries, it would be known just how many people could live without threat of starvation during the bad periods, and some sort of reproductive control might be needed to accomplish this. Shaman medicine might come into play here, if an herb was found which caused temporary infertility, without much else in side effects. The civilization would have to have some rules for who is allowed to have how many children, but they could be any type of rules at all, as long as the maximum was not exceeded.

Thus, it is not difficult at all to envision a civilization which had a limited population over a long period. It just needs a geographic limitation enshrined in the tradition and the religion, and a means of controlling reproduction, such as a herb or other plant product. There might be other means as well.

The implications of such a civilization are substantial. If the civilization lasted for many millennia, scientific knowledge and technology would be developed. It might take ten or a hundred times as long as if the entire world were full of people developing scientific concepts or engineering solutions to problems, but there does not seem to be a critical mass of people below which science cannot develop. Perhaps there is one, but it might be ten thousand people, and the civilization could be imagined to be larger than this. So, slowly, slowly, technology grows inside this ancient civilization. But because of the limit in population, it would not grow in a wide a domain as it could were the population a hundred times larger. Certain things would be developed, and that field might be explored, and then some time later, a different advance might be made. So, while technology was developing in the small civilization it would not be uniform.

Technology does not develop in a chaotic form, as there are certain advances which have to be made in order to enable the research needed to develop other advances. In our world, genetics had to wait because the technology of DNA analysis was needed first, and it needed computation and some materials developments. In a limited civilization, these pathways would be much more severe. If the civilization lasted only five thousand years, perhaps only some basic chemistry and physics would be accomplished, together with some engineering capability. It is quite likely that working with natural materials like rock of different types would be one that would be developed earlier in the civilization's history. Thus, finding some evidence of precision rock machining is more likely than, for example, asphalt reside from airport landing strips. Carefully thinking out what could be developed in stages might lead to some more clues as to what signatures there could be from small, ancient civilizations.

The challenge of finding such signatures is daunting. Even if someone could come up with a proposed list of them, there is the difficulty of knowing where the civilization lived. In our example, there is only one spot on planet Earth where the signatures would be found. Even if there were two or three, it is still a formidable problem to find them. One could try and figure out where the civilization would choose to be, but that makes the assumption that they searched around over some wide area and picked the best spot and settled there. Starting the settlement seems more likely to be a matter of chance. It might depend on where some proto-humans were when some critical mutation increased their intelligence or when they figured out how to grow a crop on a river delta where they could stay, without continuous migrations using slash-and-burn agriculture. Any number of unguessable things could lead to the foundation of the home valley of the civilization. Thus, it might be necessary to search all river valleys for their location.

It might not have been a river valley where they decided to stay, although that seems a likely choice. A lakeside location is possible. If agriculture was not as dominant as we might guess, a prolific forest area might be a choice. Again, some careful thought is needed to first construct a list of the types of areas that might be chosen, and then to narrow down the possibilities for each. An even greater problem is that this civilization is supposed to have existed tens of thousands of years ago, when the surface of the Earth was a bit different than it is today. So some geology would need to be done as well. This is indeed a difficult problem.

Why Now?

Asking the question about whether there could have been a more advanced civilization of humans that was eliminated in a catastrophe, or related questions, leads to some deeper ones. Why did intelligent humans evolve at the time they did? Why didn't we evolve into city-living, culture-appreciating, educated, adept, clever humans two hundred thousand years ago? What delayed our approach? Why weren't we delayed another hundred thousand or two years? Why now?

One way of looking at this is to examine the preconditions for the final leap of evolution, to thinking brains and everything they required, and see when they arose for the first time. The simplistic solution is to just make a list, accurate as possible, of what steps led to humans and see why one of them couldn't have happened earlier.

One detail needed to follow this approach is to decide just where on the taxonomy of animals intelligence could have arisen. The pat answer is that we needed thermally regulating bodies so our brains didn't turn off in the winter. Why is this true? What about evolving in a region with fairly constant temperatures over the year? Perhaps it is a day/night temperature difference that excluded reptiles from becoming intelligent. Suppose some lizard had a complex brain, but could only think during the day when temperatures were warmer; why is this an impossibility? During colder temperatures only the lower brain stem, which is what today's reptiles have, was working. That part would allow the reptile to live like other dumber reptiles, except when temperatures got warmer, and then it could think great thoughts.

If we cannot determine some incontrovertible reason why reptiles couldn't have become more intelligent, the boundary of time when intelligence could have started is pushed back, hundreds of millions of years, when, supposedly, reptile species ruled the entire planet. We should ask: what good would being able to think more complex thoughts do for a reptile? Their ability to survive and reproduce depends on their visual skills, their speed, their ability to recognize hiding places, their ability to capture prey using body and head muscle linkages with eye coordination, and perhaps a few other things. Nowhere in this list is anything that a complex thought might help. Compare that with chimpanzee-like species which could begin to use found objects and then shaped objects as tools. Tool-using elevated species from chimpanzee level to human level. Current eptiles don't have the physiology for that.

So, could we have reptiles of millions of years ago, those who were living in forests, take an evolutionary jump to climbing trees and developing opposing thumbs and dextrous hands? If evolution could do this, why not, over another million years of evolution, could they not develop thermal regulation to some extent? Thermal regulation requires energy, and could reptiles become better hunters or more complete omnivores, and simply follow the pathway to intelligence that proto-chimpanzees would follow millions of years later? Why weren't the steps needed for intelligence, whatever they might have included, completed long ago, in the millions of years scale.

Perhaps evolution couldn't make the total number of jumps needed for this, simultaneously. Was the jungle many millions of years ago more hostile to the growth of intelligence that the forests of a few hundred thousand years ago? What about hands? Some animals climb trees using their claws, which penetrate into the bark or catch on irregularities in the bark of trees, and evolve so that this method improves, as opposed to developing grasping hands, which is a totally different evolutionary path.

Without grasping hands, evolution couldn't take one of its sideways steps. A sideways step in evolution is when a species either mutates its genome by moving one section to another place, perhaps copying it there, which then allows the species access to some new capability, not related to the one for which the genes had evolved for. We can think of the software side of evolution, which is what happens when one generation imparts some wisdom to the next one, which allows the newer generation to use its mental and physical capabilities in a task that it wouldn't have, without the training.

What else in evolutionary pressure serves to force hands to develop? If the species lives on fruits and other pickable objects, hands might be useful here. Alternately, if the animal simply eats leaves and flowers for nourishment, then hands don't play much of a role and wouldn't be selected for in the evolutionary process. Fruit provides more concentrated nourishment that leaves, as do seeds and some roots. Was food selection the problem that kept reptiles from becoming intelligent millions of years ago?

This doesn't sound correct. Why couldn't reptiles evolve to eat fruit and seeds, if primates could? Were there fruits around millions of years ago in the equivalent of forests?

Perhaps the question should be asked in a completely different way. How do we know that some lizard species did not develop intelligence of some sort two hundred million years ago? Would there be anything detectable this many years after they became extinct? Perhaps the intelligent lizards lasted a million years and build cities. What kind of rubble lasts two hundred million years? Do we know how to do excavations to figure out the answer to this question?

One thing we do have is fossils. Fossils occur when some animal does some stupid thing and gets caught in some mud and dies and then the mud turns to stone. Because of some perversity of nature, braincases are not often found in fossils. But recently some have.

To be intelligent, one needs a large brain, measured in terms of brainweight to bodyweight. Some recent finds of reptiles raises the possibility that some of them may have larger brains that has been expected by the earlier-discovered fossils. If we assume that civilized reptiles two hundred million years ago managed to largely avoid getting stuck in mud pits and turned into fossils, then their absence in our dinosaur skeletal displays in the different natural history museums around the world is understandable.

What else might be left behind from a civilizatin of intelligent creatures that lived for a million years and died out two hundred million years ago? What might get buried and refound that would last two hundred million years? For early human civilizations, we look at burial mounds. These are put together in the first few thousand years of civilization, and then everybody stops doing it. Inside these burial mounds there are gold ornaments and jewels, which might be contenders for enduring the forces of nature for millions of years. Would a civilization that lasted much longer not simply collect these things from their own archaic burial mounds and put them in a museum? And since the Earth changes its profile in much shorter times that two hundred million years, moving dirt and rock and lava and water and any materials around on the planetary surface, how could we expect anything from an ancient city to survive. Maybe they invented materials that were more durable than concrete? Concrete might be good for tens of thousands of years, if no earthquake or flood gets to it. What is left after a short time such as a hundred thousand years? Rubble. Maybe there might be some chemical test to see if some rubble we find has some unique features? Rubble near the surface probably wouldn't stay in one place, however.

One thing we can detect for long periods, in very unique situations, is the materials embedded in layers of rock. That is how we suspect a large asteroid hit the planet some 65 million years ago, from the thin layer of iridium-rich deposits all around the world. Would the lizard civilization have put something into their air which would be detectable? It is very hard to think of any possibilities in this area.

The conclusion is beginning to look inescapable. There is no way to tell if we are the first intelligent species to emerge on Earth. All the hubbub that goes on about aliens on other planets coming to visit us might be expanded to ask if there were some 'aliens', of the homegrown variety, right here already. If it could have happened once, maybe it could have happened twice or more times. All of these things would leave no evidence. One result of realizing we might be the tenth intelligent species on Earth rather than the first is that we really don't have a good understanding of evolution yet. Maybe there are clues buried in the genomes of the organisms of Earth that indicate something intelligent was around a very long time before us. It is certainly not clear how this might happen, but we need to grasp at straws to answer this question.

Chromosome Genetics

Knowledge abounds here on Earth about the number of chromosomes humans have and how gender is determined by whether a fertilized egg cell has an XY or XX chromosome pair. It's less well known that cell division includes the opening up of all nuclear DNA pairs and the splitting of them into two batches before replication. Even less well known is how hard it is, given today's technology, to separate chromosomes so they can be accessed individually.

It is not exactly clear if there is any other way of harnessing the protein synthesis control capabilities of DNA so that alien cells might have a different way of doing it. Nor even is it known if there are alternatives to DNA to carry genetic information. Genetics in this area is like exo-planetary studies before any exo-planets were discovered. Everything is speculation.

These two questions are somewhat independent. If an alien planet had non-DNA genomes, that still does not mean that they would not have all the genetic information divided up into chromosomes. The alternatives are to have more than one nucleus in the cell, with perhaps one chromosome in each, or to have one nucleus with only one chromosome pair having all the DNA or its equivalent. Why did Earth evolve multiple chromosomes, or rather, why don't all species have just one large circular chromosome as do many single-celled organisms? What is the evolutionary advantage and would it be universal, meaning on other planets as well?

Among contemporary bacteria, there are some with one, two or more circular chromosomes, some with linear chromosomes, and some with a combination. After billions of years of evolution, the competition for a chromosomal shape has not been won by any arrangement, so for bacteria and other prokaryotes at least, there must be little evolutionary advantage between them. This is not true for eukaryotes, multi-cellular organisms, which all seem to have linear chromosomes. Most eukaryotes also have some legacy circular chromosome material, located in the mitochondria or elsewhere, which reproduce independently of the nuclear DNA during cell division.

One advantage is obvious. To have genetic information for many different types of cells, as well as the signaling information for organizing them, there must be much more information, and a circular chromosome or a single linear chromosome with all this information would simply be too large to fit into the nucleus, or for the meiotic proteins to handle. Having everything in large numbers of diverse mitochondria also seems evolutionarily difficult, for the organization of cell replication. So, using DNA or anything else, it appears likely that alien species will have multiple linear chromosomes.

Alien geneticists may run into the same problem that Earth geneticists have: separating chromosomes is difficult. The processes within the cell are quite complex, and there is not enough information on them to allow them to be replicated or imitated in a genetics lab. Neither have there been any simple mechanical solutions to separating chromosomes. Perhaps we are missing the right discovery. By the time asymptotic technology arrives in the genetics area, however, this problem will have been solved.

It's not clear that the ordering of advances and inventions in the genetics grand transformation will make much difference in how an alien civilization will develop. The end result would be the same. But chromosome separation would allow some cost-savings in making genetic changes to organisms, or to the creation of synthetic organisms. If this cost-savings is large, it would emphasize the possibility of having genetically modified or created organisms throughout the civilization.

All we can do now is map the genome of humans and other organisms, and use that information for diagnoses, or in plant and animal breeding. There is some work being done on inserting novel genes into existing plant and animal genomes, but it is very slow. If it were possible to isolate chromosomes rapidly and inexpensively, this would speed up the process. It would also make the process of genetic modification more certain, as a laboratory could simply work with one chromosome and modify it, without having to worry if the modification methodology would accidentally make a modification in another chromosome, with a similar stretch of DNA.

One interesting question to ask is how would an advanced alien society prepare the genetics of their successive generations of their population. Suppose there is an inexpensive way to separate chromosomes. Then, the alien society could simply decide to choose the best set of chromosomes from the copies available. If there is some optimal set, then all the aliens in later generations would be like clones. Alternatively, if the selection was out of the set of a pair of parents (assuming two genders), a wide variety of individuals would remain, but there would be a trend toward more healthy individuals with better capabilities.

Similarly, if there were pairs of parents with some genetic deficiency in one chromosome, specifically in one of the parents, then that chromosome could be eliminated in the resulting next-generation individual. This would result in the gradual elimination of genetic diseases and other problems, although errors in replication remain possible and there would always be a risk of some new mutation arising.

There are many syndromes which arise because of the improper copying of whole chromosomes, meaning extra copies, and with chromosome separation technology, these would be reduced or eliminated as well. Broken chromosomes could be sorted out as well, and mutations arising from copying errors would be detectable and removable. Reading the genome would be less computationally intensive and less prone to mistakes, if each chromosome was read individually. The current Earth method of batching all the chromosomes together and then sorting them out after all the fragments have been read is clearly something that can be improved on.

The technology to separate chromosomes does not seem to be on the horizon, meaning the old methods would be used here for a decade or so. Microbiological investigation into how to make a cell nucleus separate and then how to create microtubules to reach into the mixture and connect to individual chromosomes needs to be done. Once it is well understood how nature accomplishes this task, it would be more reasonable to expect that genetics laboratories can come up with some combination of biological and physical equipment to accomplish chromosome separation. After this, we might see genetics jump forward very fast in potential applications, and this will give us a much clearer idea of what an advanced alien society might be doing with their own technology in this area.

Hunting for Life in the Milky Way

In earlier posts, there was some discussion of what would be the goals of an advanced alien civilization, assuming they had come together to choose one and then to work on it. In a different blog, some more thinking on this matter indicated that the most reasonable and likely goal of the civilization is that of life itself, which is best broken down into five separate goals, survival, reproduction, adaptation, evolution and dispersion. These goals imply many choices that the alien civilization would make, in order to further their alignment with these life goals. The last goal is dispersion, and that means first expansion all over the planet, then the solar system, and then outwards into the galaxy. Just think for a minute what this implies: all or most advanced alien civilizations are going to attempt colonization and seeding, both of which support the dispersion of life.

Neither of these tasks are easy, as has been noted in all the posts in this blog on these topics. Colonization means setting up some replica of the alien civilization on an exoplanet ,while seeding means starting out life with the alien version of DNA on some planet which doesn’t have the prerequisites to become an origin planet on its own, but can support life, being in the habitable zone plus all the other conditions. Current theory here on Earth indicate the cells that did that were cyanobacteria.

Looking for seeded planets would likely be the same as looking for origin planets. Seeding might put photosynthetic organisms into a planetary ocean, and then, after a few hundreds of millions of years, an oxygen atmosphere might exist, which is a tremendous benefit for evolution, allowing life to expand beyond chemotrophs and cyanobacteria cells to a food chain. The oxygen in a seeded planet’s atmosphere would look the same as in an origin planet’s atmosphere.

So, assuming most of the alien civilizations do both seeding of potential life-supporting planets and colonization of others, which are not able to support life, but which provide the resources necessary for the alien civilization to sustain itself for a long time. Which ones should be looked for?

Seeding a planet gets over the hump of life origination, which might be tremendously difficult, rare and improbable, at least according to one theory, mine. Is evolution fairly certain after that, or are there more highly improbable-to-overcome barriers along the way to intelligence? Suppose there aren’t. Suppose evolution is as easy as rolling down a hill. However, it takes a long time. Earth is our only example here, and life took about two and a half billion years after the atmosphere changed to partially oxygen to evolve to intelligence. This means that any alien civilization which evolved in the last two to three billion years has not had enough time yet for their first example of seeding to have led to a new alien civilization, evolved from cyanobacteria to tool-using creatures of one form or another.

This raises the obvious question of when, in the history of the galaxy, was life likely to originate? There are stars around which are ten or so billion years old. Could these have had planets soon after they formed, and perhaps one which met the prerequisites for life to originate? Unfortunately, current astronomical tools do not allow us to figure out much of the history of the galaxy. It likely started out as a gas blob, and condensed irregularly, with stars forming all over it, but more in the denser region in the center. Gas was more dense that now, as by now much has been consumed in star formation, and that implies that stars which formed early would be larger. Large stars live short lives, and end in a supernova explosion. There would not have been the neat division of the galaxy into the disk and the central bulge, so star motion would have been more random and Boltzmann-like. Neither of these two things bode well for planets. Supernovas going off near a planetary system sterilize it, but may also disturb planetary orbits, causing them to be ejected or rarely crash into the star. The passage of a nearby star does the same thing, pulling planets out of their orbit, leading to a planet-planet interaction where the smaller ones get ejected. So, while little definitive is known, it would seem likely that planetary formation in a system which perseveres long enough to originate and evolve life is more likely in the later stages of the galaxy and out in the disk. Finding planets to seed would also be more likely in these conditions.

Putting this together means that seeded planets might be around, but life on them is too young to have evolved into an advanced civilization. There really is a double time here. For life to originate and produce an alien civilization, capable of star travel, might take four billion years since the planet formed into a habitable world, with the right temperatures and everything else needed for life. Then if that civilization seeds another planet, we have another three billion years or so to wait. That is seven total, and seven billion years ago, there might have been so much turmoil in the galaxy that life couldn’t originate and evolve. So, planets which have been seeded might be common, and even many which have had the few hundred million years to produce an oxygen atmosphere. But if we are hunting for alien civilizations, seeded planets are not worth the effort. That leaves origin planets and colonized planets.

The previous post, on frozen worlds, indicates that colonized worlds, if the aliens choose worlds which are the easiest to colonize and which will sustain them for a long time, might look absolutely different from origin worlds. It also indicated, because of the very different time scales involved, that there could be very many of them all over the Milky Way, or at least out in the disk. The idea was simple: if there are sufficient resources on the planet, fusible and fissionable elements, plus all the other minerals necessary to supply the civilization with its raw materials, buried in the ground, they can simply build their civilization under the surface, on a frozen world and maybe some not so frozen. The ratio between colonized worlds and origin worlds might be a thousand to one. There would also be much larger numbers of previously colonized worlds where the alien civilization has used up the minerals and life on the planet was no longer sustainable for them.

How do you detect a mine shaft and a starship landing zone? Maybe there would have to be some surface transportation, if they needed to have mines in multiple locations. It might be possible, with a kilometer sized telescope, to see large oceans on an exoplanet in our vicinity, but even one ten times larger than that could not detect something as small as tens of meters or even a kilometer in size. Looking for a tiny heat source is conceivable, but unlikely as the resolution at deep infrared wavelengths is so much less than in the visible. If the concepts trotted out here and in the last post are viable, it means that alien civilizations are not detectable, and they would have no interest in coming to Earth, either for seeding as we are way past that, or colonizing as there are too many potential difficulties. It wouldn’t align with their goal of dispersing life at all to visit Earth. So the only thing we have any hope of doing is detecting an origin world, but if there is only a few of them,they might be on the other side of the Milky Way or in a different spiral arm. Perhaps a double hope of there being easy ways to originate life and our detecting oxygen in exo-planet atmospheres is the only possible salvation for the quest to find aliens.

Later Stages of the Genetic Grand Transformation

In an older post, it was noted that the genetic revolution is likely to be, by a large margin, the most revolutionary of all, in the sense that an alien civilization will be wholly transformed when it happens. The different stages of this grand transformation can be laid out, as they are necessarily sequential. The knowledge gained at one stage is needed for the next stage.

The first stage is very simple, chromosomal selection for embryos. This is extremely old news here on Earth, and there has even been a movie produced about it, entitled GATTACA, from twenty years ago. A couple has twice as many of each chromosome as an embryo needs, so the best two of each type can be chosen. The second stage is what we hear in the news nowadays, which is when specific genes are chosen. Tools for that are just now being found here, and surely in any alien civilization reaching its maturity this would be as routine as antibiotics. Small amounts of changes are what we talk about now, as we don’t have confirmed technology for even that. The technology must exist, however, as inside the cell, genes are moved around during evolution all the time.

Right after that, industrial gestation would be the likely mechanism to be developed next. This particular invention will change an alien civilization more than the Internet has changed out, which is totally. No more parents and no more child-bearing, just new humans. Will parenting become a specialized business, just as has almost every other aspect of life? Why would it be any different? Parenting is extremely rewarding, perhaps more so than any other activity in life, but why not outsource the child-bearing to a machine? Yes, bonding between mother and child will be diminished, and in time, as an alien civilization ages, the role of mother might be also performed by specialists, either trained aliens or some robotics. It is almost trivial to be able to think up problems that might happen with this, but it will be just as trivial for an alien civilization to figure out how to avoid them or turn them into advantages.

Consider for a moment what this point represents. It means that any organism that can be developed in a laboratory can be put through industrial gestation and be ‘born’. This refers to things on alien planets like mammals, but similar processes would be similarly possible for things like plants and insects and whatever else evolved on the planet. In other words, life becomes something like a recipe or a cookbook. AI will undoubtedly be very powerful by the time industrial gestation is well-developed, so the concoction of forms of life which can successfully pass from the egg stage to the real world and on to an adult animal or plant will be quite possible. A huge amount of data will have to be collected, about all the molecules that operate in a living organism, but huge data stores are just the media AI likes to live in.

Now, on Earth, to come up with a new species of plant or animal takes a lot of careful breeding and selection. On a planet with technology a few centuries past ours, it will be done from scratch, without experimentation, as ontology and growth can just be simulated. There can be as many new species as anyone wants to take the time and expense to come up with.

This is by no means the end of the genetic grand transformation. Since reproduction of anything will be economically done industrially, why would there be any species at all? Species are defined as groups of individuals capable of breeding with one another. There would be no need for this, so why have species? There could be a billion clones of some plant if it were desired, or none, meaning that organism was its own species.

Is DNA sacred, or whatever form of organic molecule evolved on an alien planet to serve as the template for genetics? We on Earth are far from knowing how many kinds of molecules can do this job, and if there are more than one, is there another which is more versatile, or more reliable, or easier to work with, or anything else which might mean that the alien technologists would start switching over to it for successive generations of organisms?

And whether DNA or XYZ is used, the legacy method of ontology might be changed. We don’t understand this process very well, but we have observed it in detail. The idea is that each successively evolved species keeps most of the ontology of its predecessor, and adds a little twist to it. Perhaps an alien civilization would rewrite the book, and have a completely different order of development of organs in some new organism they created. Just because something evolved does not mean it was the best that could exist, as there is a barrier posed by the need for evolutionary change to work gradually.

One point made in that earlier post is by the time of these later stages of the genetic grand transformation, it might be reasonable for aliens to switch over from mono-genetic organisms to multi-genetic organisms. We refer to these as chimeras, but that is only a tiny little glimpse of what might be possible. Any optimized genetic package can be used for any organ or part of an organ in a designed chimera. Aliens could choose to use just two or as many as desired. This would mean that an embryo would be fashioned by amalgamating cells of different genetic varieties, all of which were tuned so they could form a cooperative package of cells that could be gestated and have different genetic codes in different parts of the organism.

All the previous stages involve organic biochemistry. At some point, there could be a closer bond between organic and inorganic components in some hybrid object. We on Earth use certain types of microbes to sort out dilute liquids containing minerals, and of course that should be expected to expand far beyond these ideas. For example, technology may well allow communication between whatever passes for neurons on an alien planet, and some semiconductor gizmos of equally small size. The neurons would be tailored genetically for this, and the gizmos specifically designed and printed to be a good substrate. Then anything is possible.

Authors and screenwriters like to play with the idea of a person from some centuries ago being brought into the modern world and being astounded by what they see. Someone from before the genetic grand transformation being brought to a time after it would be immeasurably more confounded by what is seen. We on Earth would do well to simply contemplate these potential changes to better appreciate what an alien civilization of advanced technology really looks like. Then we can better ask the question of why haven’t they visited us here.