Making Aliens: The Repercussions of Planetary Settlement

by Athena Andreadis

Why Go at All?

Humans possess two interesting characteristics. The first is our curiosity: we have an insatiable need to know our universe. We've investigated our surroundings ever since we became self-aware. That inquisitiveness pushed us out of our original home in an African savanna and drove us to explore and occupy our entire planet, regardless of the local environment. The second is our ability to envision a destination before we actually embark on the quest. As with many of our capabilities, this is a double-edged weapon. It motivates exploration, but it also colors expectations. So it can distort reality, and act as an obstacle to understanding and accepting real discoveries.

Our curiosity and our yearning have fuelled our vision of exploring space. Until now, our dream of space exploration has rested on two very deeply embedded but rarely discussed assumptions. One is that humans can overcome everything, given enough technology. This outlook is not surprising, given that the primary movers behind the endeavor have been engineers. Another is that (taking into account our technological prowess) settling on other planets will be about as difficult as it was for our hominid ancestors to expand across the Earth.

Both assumptions are false. Some people advance the argument that humans are really not native to Earth, just to the African savanna. The conclusion is that since we colonized the entire planet, we can do the same with Mars or any other planet we put in our crosshairs. However, there are some fundamental biological limitations that technology cannot address. And these limitations are real enough, since they have prevented us from settling the terrestrial oceans, whose conditions are a distrorted yet faithful mirror of those on Mars -- namely, a fatal pressure differential, unfriendly temperature and an unbreathable atmosphere. Contrary to what we like to believe, humans, like all complex systems, are inherently fragile and completely dependent on both external and internal ecosystems.

At first glance, we're miracles of flexibility. Among advanced mammals, our physique is the least specialized and our brains the least hardwired -- at least at birth! With the exception of our manual dexterity, we're physically mediocre at everything else, jills and jacks of all trades and perfect for none. Our brains, too, can reroute and rewire almost at will, if presented with the crucial information at the right window of opportunity. So, for example, it has come to pass that we click computer mice and drive cars, skills never required of our tree-swinging ancestors.

However, this power of our mind, which made us wish to understand our universe and enabled us to take the first steps towards such a goal, cannot overcome all obstacles. Plainly put, humans are native to this planet in all aspects which matter. Perhaps terrestrial life originally arose from some version of panspermia. It may have arrived from Mars when it was the favorite within the Sun's habitable zone, dropped out of the sky from contaminated comets or seeded by experimenting aliens. Regardless of origin, the seeds were at most at the bacterial stage. We know this from the fossil record, from the fact that all earth life has the same genetic code and because all terrestrial species are, to a large extent, optimized for this planet.

At this point, humans have overrun the earth, to the point of endangering its miraculously favorable but fragile ecology. If we cannot stabilize our population and do not wish to give up the wasteful first-world living style, our only other choice is to expand outwards. Even if we reach environmental equilibrium, exploring and colonizing other planets is something we must eventually attempt to survive our sun's evolution into a red giant, regardless of how well these New Worlds can accommodate us.

So when we venture into space long-term, we have to deal with questions beyond the enormous cost and technical difficulty of the enterprise. Can we bridge the enormous distances between stars without forgetting either our technology or our mission? And can we flourish in a place that is not optimal for us -- which, by definition, will be every planet we encounter, as well as the spaceships that take us there?

The Journey

The distances between star systems are truly vast. To reach Mars, our nearest neighbor, takes six months with our current propulsion systems. Even fusion drives or light sails will not shorten stellar trips by much. Truly exotic means, such as warp drives and stable wormholes, may never leave the realm of fantasy because of fundmental constraints -- the lightspeed limit may prohibit the former, gravitational instability the latter.

So our current alternatives are the so-called "arks" or long-generation ships, which have to be enclosed and self-sustaining. The trouble is, we have never successfully engineered such a system, and the gobs of waste circling all our space vessels (particularly Mir) are sad witnesses to this fact. Biosphere 2, the first experiment to attempt creation of a totally enclosed, self-sufficient environment ended up with oxygen leaks, ecological breakdown, and severe carbon dioxide poisoning -- plus virulent infighting among the participants.

Fortunately, Biosphere 2 was set up on Earth, where the surroundings could easily come to the rescue. That will not be the case for a ship halfway to another planet. In this respect, environmentalism with its insistence on recycling and conserving resources is not only a good strategy for our increasingly crowded planet but may also devise partial solutions to the problem of long, slow interplanetary journeys.

A long journey has additional associated dangers beyond ecological breakdown. One is the loss of biodiversity for all the species within the ship, including the human passengers. Another is mass psychosis, which can grip entire nations and will be far more dangerous in an isolated context deprived of outside corrective influences. Either can lead to the loss of technology, which has happened here on Earth as a result of discontinuities from environmental catastrophes, large-scale migrations or disruptive conquests. Classical Greeks and medieval Europeans forgot the sophisticated drainage and sewage systems of the Minoans and Romans, respectively; the Native Americans forgot the wheel; the Tasmanians forgot boats and even fire. The persistent refusal of NASA to study complicated human interactions in space, including sex, has left us ignorant and highly vulnerable in this respect.

If a spaceship loses technology, its passengers may not be able to survive on a hostile planet. Terrestrial examples of isolated settlements illustrate this danger. The medieval Norse settlements on Greenland as well as several European colonies in New England perished from malnutrition despite their high-tech beginnings. The Polynesians of Pitcairn and Easter Islands stripped their lush islands of vegetation (thereby breaking down their ecology, losing all trade and cutting their communication lines). Their solution was to resort to cannibalism, which led to their extinction within a few hundred years of their arrival.

The Landing

Even if we come up with propulsion systems that shrink the distances between the stars, they are just the overture to a very long and difficult opera. If our venture out is not to be merely a more expensive repetition of our vanity foray to the Moon, we have to give serious thought to how we will live on extraterrestrial planets.

Like good representatives of humanity, we will address this question through technology -- but the vital question is, which technology. We have three choices:

1. closed systems -- terrariums for people such as Biosphere 2;

2. terraforming -- making other planets Earth-like; and

3. genetic engineering -- changing ourselves and our imports to suit our planet host.

Science fiction, especially in its film incarnations (with its preference for filiming in California), has spoiled us by postulating a universe that is excessively endowed with Earth-like planets. Even when shuttles are forced to perform unscheduled emergency landings, they invariably crash on planets where neither breathing apparatuses nor protective clothing are necessary, and which often tempt the crew with hanging fruit. But how likely is the existence of all the Xerox copies of Earth that have been paraded throughout sf films and series, from Star Trek to Star Wars?

At this point, evidence is steadily accumulating that Jovian planets are circling other suns. Where big gaseous planets exist, small rocky ones also must lurk. Nevertheless, all the planets that belong to the same class as Earth will differ widely in their outcomes, just as tiny details in our local drawing boards have generated environments as different as Earth and Venus, and on Earth itself hot springs and frozen mountains, and lifeforms as diverse as roses and sea urchins.

The final state of a planet depends on a huge number of variables -- type of primary, distance from primary, system configuration, planetary mass, rotation rate, inclination of orbit, number and size of moons, thickness and composition of atmosphere. So, contrary to the optimism of science fiction, we're unlikely to ever find a twin Earth. If we find planets within another star's habitable zone, we will probably need to either terraform them extensively or genetically engineer the colonists so that they can survive without external aid -- for example, make them able to hibernate. But let's suppose that we do find an unspoiled second Earth. Even if it fulfills all the requirements of the long astrophysical/planetological list, details are also important

For instance, one issue rarely discussed in science fiction is that all molecules involved in life display the property of chirality (Greek for "hand"). That is, they are fundamentally asymmetric. Life on Earth has exclusively chosen one of the two possible configurations -- the "left-handed" orientation -- and has stuck to it throughout its evolution.

If the biochemistry of New Earth is right-handed, we won't be able to digest any native foodstuffs, because our digestive apparatus will not be able to degrade them into useful units nor use them for energy. No matter how luscious the fruit appears, it will be strictly eye candy. The alternative will be to introduce terrestrial animals and plants, which may overwhelm indigenous life.

Other problems could doom would-be colonizers. Gravity significantly lower than terrestrial will make our muscles atrophy and turn our hip and leg bones brittle. More crucially, gravity seems to play a role in embryo formation and in correct configuration of brain synapses. It will avail us little to go to another planet, if we cannot have children, propagate plants -- or think straight. Even subtle shifts will lead to problems: for example, we have an in-built circadian rhythm of about 24 hours. If you think jet lag is bad, imagine what it would be like to suffer from it permanently, living on a planet whose length of day differs greatly from that of Earth. Just as a day of different length will confound our biological rhythms, a primary star of a different color will do the same to our vision (as explored by Ursula LeGuin in her short story, Persistence of Vision).

Such dislocations would drastically decrease our ability to survive, because the compatibility of inner and outer cues intimately affects competence and health. Too, recent results from orbital experiments show that mice born in low gravity have a permanently different sense of balance and of 3-D space and, unlike adults transiently exposed to low gravity, they don't re-adjust their brain wiring upon return to Earth. Contemporary Westerners tend to forget that even Earth presented humans with major survival challenges before engineering and medicine relegated most of them to dusty museum dioramas

Even if we find an ideal planet, should we try to colonize it, given the dismal record of human colonization on Earth? An Earth-like planet could harbor intelligent indigenous life, though some scientists believe that self-aware intelligence might be very rare in the universe. They point out that humanity is the only species that became sentient on Earth, even though billions of other species have existed during the planet's 4.6 billion year history.

I think that is too pessimistic an assessment. The fact that humans stand alone does not preclude non-human sentience, on Earth or elsewhere. Once humans developed intelligence they cut off the possible evolution to sentience of any other terrestrial species, even of close humanoid cousins who were already making the transition to high intelligence. The dice of evolution never fall the same way twice. If events had occurred just slightly differently on Earth, humans wouldn't have appeared. For example, the impact of the large meteor on the Yucatán Peninsula 65 million years ago, which wiped out the dinosaurs, gave mammals their big chance.

Though humans are unique in the cosmos, intelligence most likely is not. If a planet is Earth-like enough to tempt us to settle on it, I think it will be favorable enough to eventually grow its own version of intelligence. This raises a serious ethical dilemma, and past human behavior is not reassuring on this point. This is why we need to send the ships out early, before Earth runs out of resources. If we send out expeditions at the last possible moment, when our very survival is at stake, we won't have the luxury of factoring ethics into our equations and we'll undoubtedly swarm over the new planets like army ants, denuding and devastating as we go.

Playing God I

No matter where we go, if we choose to settle we will need aids for living at the start, so bubbles and domes will be inevitable for the early generations. However, for long-term exploration and living, adaptations are unavoidable, unless we want our new worlds to resemble prisons or intensive care units. Therefore, for the long haul, it will have to be terraforming, genetic engineering or, most likely, a combination of the two

Terraforming has been the darling of engineers and planetary physicists, for several reasons: it is macho; it bristles with gizmology and makes gods of engineers -- geeks becoming builders of worlds, games of SimCity turning into the real item. Terraforming is morally palatable at first glance, unless the planet to be terraformed has advanced endogenous life.

None of us would bat an eyelash at depriving bacteria and fungi of their niches, and most of us would tolerate the destruction of lower flora and invertebrates. On the other hand, we also dream of extraterrestrials as ahead of us as we are of invertebrates stepping down from on high bearing such gifts as immortality recipes and stable wormholes. Would we give equivalent gifts to beehives, which exhibit a certain kind of hardwired collective intelligence? My point here is that the cutoffs are dangerous slippery slopes, especially if one day we expect to be hosts to ET visitors, rather than unexpected guests on planets that lack technologically sophisticated stewards.

A second point is that even if the endogenous life is advanced, we may fail to see it in time -- a strong possibility, given that life beyond earth will be so different as to be incomprehensible (such as the sentient ocean in Stanislaw Lem's classical novel, Solaris) and also given that our current primary indicator for intelligence boils down to the rather crude metric of technological prowess. Earth species are as similar to us as they can be, yet we still cannot agree if whales or elephants are intelligent -- or even our cousins, the higher apes, who have recognizable family and clan configurations and who also transmit acquired knowledge to their offspring, including rudimentary technology. In fact, the closer our host planets are to Earth, the more likely it becomes that they are favorable to life, and the least likely the natives will be to survive terraforming unscathed.

As it stands, not even Earth has done too well with terraforming. Straightening of rivers has led to horrific floods and avalanches, damming has extended the domain of diseases carried by insects and rodents, the building of enormous cities is straining their local environment -- witness the ever-expanding desert around large cities such as Brazilia and Los Angeles -- and the habits of the First World have started a greenhouse effect and blown a hole through the protective ozone layer. Even now, we come up with new facts about terrestrial geology that give us pause. A new planet will be a much greater mystery and delving into it without adequate knowledge may well destroy it. Furthermore, unless we have technology at Kardashev level II, we still won't be able to change a planet's rotation rate or its distance from its primary, the two major determinants of climate

The other sticky point about terraforming is that not only are we really clumsy at it, but we are also not long-lived enough to really follow it through. Even if we find ways to extend our lifespan, our time horizon is too short to allow us to be gods. The projections for terraforming Mars hover around thousands of years. Humans are clever and industrious, but their attention span is finite.That of an American politician hovers around two years. It is unclear that such a long project can be sustained unless it is turned over to a priesthood, thereby setting a dangerous precedent whose consequences are well documented on our planet, whether we are talking of the Catholic church or of the NASA upper echoelons. Even if we entrust the task to machines, they won't be able to gap such long time spans unless we make them self-reproducing and immune to programming mutations. Terraforming is like sculpting clay with a shotgun: you shoot at the clay until something emerges that you can live with -- if there's any clay left at that point.

Last but not least, terraforming is a failure of the imagination. Why would we want to turn other planets into second Earths? The terraforming approach reminds me of the English missionaries to Hawaii, who dressed in boiled wool and ate boiled meat while surrounded by hibiscus trees, warm waters and a sophisticated maritime culture -- or, closer to home, of people who go on expensive package tours but insist on eating at McDonald's in Paris.

So if we really wish to be an integral part of life on the new planets, rather than tourists gazing at the Serengeti from behind the glass of air-conditioned buses, we have to opt largely for the third choice: genetic engineering of the prospective colonists.

Playing God II

The expression genetic engineering automatically raises hackles -- especially in Europe, as the recent flap over engineered foostuffs attests. One reason for this is its novelty: the concept of the heliocentric system sounded equally incendiary and blasphemous when it was first discussed, to the point of getting several of its adherents burned at the stake. Another is its whiff of hubris. Altering the human germ line is considered equivalent to playing god and incompatible with free will (a strange correlative, since no human has even chosen her/his parents, gender or time and place of birth). In fact, most people seem to use the words genetic engineering and eugenics interchangeably and, granted, they do overlap and can be used for nefarious ends like any other application of scientific knowledge

Yet we do protest too much, and we know it. Everything that humans touch they engineer, whether these items are animate or inanimate. All our foods, vegetable or animal, all our clothes or structural materials which are not synthetic, our pets, our royal families, from the Levites to the Incas to the Hapsburgs, are the results of genetic engineering. Too, segments of humanity have practiced inbreeding for racial, cultural or even financial reasons -- and several cultures have additionally constricted their genotypic variety by selectively killing or aborting their daughters.

We have also practiced reverse genetic engineering by allowing the continuation of genotypes that would normally have become extinct -- from the short-sighted and disabled, who would have ended up inside the stomachs of a lioness pride under normal circumstances, to hemophiliacs who would have bled to death from a minor scratch before reaching their reproductive years.

Genetic engineering has advantages that outweigh those of terraforming by a wide margin, in my opinion. Genetic engineering requires neither nuclear bombs nor mirrors the size of a solar system. Its results can be seen within a few years, given the generation time of most terrestrial species, compared with the millennia of terraforming. Also, whereas terraforming is a linear, one-shot deal, genetic engineering resembles parallel processing in that several lines of inquiry can be pursued concurrently.

Last but decidedly not least, genetic engineering may well turn out to be economical. Species not so good for one world may well thrive on another. The hubris involved in genetic engineering is several orders of magnitude smaller than that involved in terraforming. At least we're good at the former, as the variety and quality of our foodstuffs and pharmaceuticals attest. Nor would we be condemning entire worlds or species to destruction. Terraforming is a battering ram, genetic engineering is a scalpel. Which one would you prefer for a delicate, complex operation -- whether this is repairing a watch, performing a heart bypass or fine-tuning a new world?

The Descendants

Among its consequences, genetic engineering may also reverse a problematic human trend towards biological homogenization which is as dull and dangerous as its cultural equivalent. By eventually recognizing that we are one species and interbreeding enthusiastically to celebrate that fact, we have stopped our further evolution by extinguishing isolated breeding pools. We have overtaken earth, first by being adaptable, then by dint of our technology. From a jaundiced ecological viewpoint, the recent explosion of humanity has been likened to a lemming population boom or a moth infestation. Such booms are invariably followed by busts -- and in our case, a crash would also mean irreversible loss of technology.

From our very beginnings, we tended to consider ourselves the jewel in the crown of creation. We believed that at least some of us had been created in the image of the local deity. Yet by considering our germ line sacrosanct, we have painted ourselves in a biological corner. Each terrestrial species has a finite lifespan. Moreover, most successful species branch, whereas we humans are down from a half dozen relatives to a single representative -- Homo Sapiens sapiens. If we insist in remaining unchanged, without evolving or radiating, we may degenerate and disappear without intervention of a great catastrophe either from something home-brewed like war or from a random event, such as the impact of a rogue comet. We'll blink out not with a bang, but with a whimper.

In that respect, our absolute dominance in our current configuration has not served us well for the next step. Deeply embedded in all our plans and ideas is the not-so-hidden assumption that we will fundamentally remain as we are. But the difference between living on Earth and anywhere else is qualitatively different from living in New York versus living in the Arctic. Almost certainly, if we really wish to go into space as long-term explorers, rather than as tourists, we will have to accept radical change -- and with it the disquieting possibility that we will not be the crowning spire of the next cycle, but its foundation.

Interestingly enough, we actually seem to be designed for rapid speciation. The successive branchings of the humanoid group have come at ever shorter intervals: the genus Homo arose 5 million years ago; Sapiens, 0.5 million years ago; Sapiens sapiens, 0.05 million years ago. If you put 1,000 people in a row, the first in the line would be the very first Cro-Magnon, the last in line one of us. Our species is actually very young, and almost certainly in biological flux -- except for our insistence that we are the perfected end product.

Settling on other planets will speciate humanity even if we forego genetic engineering, because it will create relatively isolated breeding pools in circumstances radically different from those on earth. Human groups also developed characteristics specific to their terrestrial environment -- the Mongolian epicanthic fold, the heat-efficient Inuit compactness, the heat-dissipating Tutsi lankiness, the enlarged heart of the Nepalese and Ecuadorians; last but not least melanin, whose dosage increased where appropriate to provide shelter from sunburn, unwittingly causing humanity endless woes. Genetic alleles that are anathema today spread quickly and widely through populations for very good reasons in the past: a mutant hemoglobin made carriers resistance to malaria, while killing homozygotes with sickle cell anemia; a mutant ion transporter did the same for cholera, but killed homozygotes with cystic fibrosis. Between the expense of interstellar travel and the discomfort from different gravity, pressure and other planetary specifics, we will see differentiation much faster.

Speciation means this, in practical terms: At some point, the pools will no longer be able to interbreed. Our colonials will not just have different accents. They won't be Brazilian Portuguese, or Egyptiot Greeks -- or even those real aliens, Australians. They will no longer be humans as we define the term. To put in succinctly, they will not be someone that we can easily love either in the fundamental biological sense or in the equally influential cultural one -- and in the end, that is the commonality that binds us.

In that respect, TV science fiction has served us poorly, by depicting humanoid aliens as ersatz samurai like the Klingons or fake Tibetans like the Bajorans. Written science fiction has done much better in presenting visions of such offshoots of humanity -- for example, Kingsbury's Courtship Rite and Cherryh's 40,000 in Gehenna. In effect, by sending out long-term planetary expeditions, we will create aliens more surely than by leaving picnic trash on an uninhabited planet. Our first alien encounter, beyond earth just as it was on earth, will be with ourselves as seen through the distorting mirror of divergent evolution.

The differentiation of humans into truly separate branches will force us to face our hard-wired fear of anyone who is almost like us, but not quite. The last true such encounter was roughly 40,000 years ago, between the Neanderthals and the Cro-Magnon, though it has been replayed in countless first contact situations between cultures ever since (not to mention the exchanges between the sexes). Ever since humans became sapient, they enhanced their self-esteem and justified their raids by insisting that those beyond the next hill (or for that matter, those cleaning their latrines and/or bearing their children) were subhuman, despite the indisputable and well-known fact that all aliens were fully human by the sole criterion that is biologically relevant; namely, production of offspring.

Such xenophobia was once a survival mechanism, but now it's as useful as our appendix and wisdom teeth. And despite our other strengths, embracing the alien is decidedly not high on our list of attributes. Certain segments of the scientific and space aficionado communities have been cheerfully discussing how to interact with Little Green Women and Men. Well, the armchair philosophers will get the chance to practice their theory when humanity splits into groups of cousins who won't look like the usual Hollywood brands of benevolent aliens -- not like angels, not like human newborns and not like snuggly, cuddly Ewoks.

This prospect is one of the scariest aspects of venturing into space, yet at the same time one of the most exciting. It's also a development that will guarantee the survival if not of our species, then certainly of our legacy. It has taken us a long time to reach a fragile and imperfect unity, cemented by the understanding that we are all really one large family. To go to the next stage, we must voluntarily renounce that unity and relax our iron grip on the evolution that we have arrested. After all, don't forget that if not for sudden jumps in speciation, most of them caused by environmental pressures -- an asteroid hit here, an Ice Age there -- we wouldn't be here. Planetary settlement helped along by judicious application of genetic engineering is merely the continuation of this trend, except that some of the process will be under our control. Stasis ends in death not only culturally but also biologically. If we don't go into the next stage, our descendants won't just lead lives devoid of meaning, doomed to repeat outworn patterns in the confines of a worn out planet. They will also peter out, dead branches of a dried-up tree.

If we allow ourselves to grow up and give rise to other sapients, it's quite possible that our descendants will be as kind to us as we were to our ancestral species. However, whether we like each other or not, I hope that they inherit our curiosity, because that's the one indispensable ingredient for success. And despite all the caveats I listed, I think we will venture to the stars -- for knowledge, for glory, but above all, because we thirst to know what is behind the next bend in the path. Compared to the oceans that we and our inheritors will navigate, our efforts until now are like the launching of paper boats in a bird fountain.

This article was delivered as a talk at the Apollo 2000 Rendezvous of the Ohio Valley Astronomical Society on June 10, 2000 and at the International Convention of the Mars Society in Toronto on August 11, 2000. It may be not be used for profit, must be reproduced with no changes, editing, or additions whatsoever, and must be accompanied by the following copyright notice: Copyright © 2000 by Athena Andreadis. All rights reserved

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