Toward Distant Suns
by T. A. Heppenheimer
Copyright 1979, 2007 by T. A. Heppenheimer, reproduced with permission
Chapter 13: Perspectives on the Future
The subject of the future is a popular one, and there is no shortage of articles and books in this area. However, most such opinions have a curiously static quality. They assume that only a few aspects will change, such as population or the availability of energy; or they grind political axes by warning of doom in tones that hint of threats to human survival; or else they promote technical miracles to flow from some new invention. There rarely is a serious attempt to reflect the richness and diversity of any human experience, including that of going forward into the future. Most of all, few authors have come to grips with the contradictory nature of different trends. Yet inevitably a topic so complex as the future must be subject to many trends that will shift in importance and influence, alternately giving and withholding hope and bestowing that gift first upon one group of peoples, then another.
With these caveats, it is appropriate to offer what after all are my personal opinions. I think that humanity will advance and advance to a time of space colonies. I think there will be interstellar flight and that our descendants will make their mark upon the Galaxy. But while we do these things, we will face new and difficult times in which we will struggle with the effects of our past growth and progress.
What may be the most significant of these effects will involve nothing so straightforward as pollution or environmental despoliation, popular though these topics are. Indeed, these effects are properly described not as environmental at all, but as climatic.
As early as the 1930s there were scientists who appreciated that the growth of an industrial society might lead to changes in the weather. It was G.S. Callendar who pointed out that the burning of coal and other fossil fuels would lead to a buildup of carbon dioxide in the atmosphere. This CO2, then would act to trap heat by the greenhouse effect, raising global temperatures. The years 1880 to 1940 were years of growth in industrialization, and meterological records showed the average temperature rose by nearly 1°F in those years. It was quite tempting to suggest that the two trends were related.
A degree of temperature matters little in a day's weather, but as a change in a global average, it means a lot. Reid Bryson, director of the University of Wisconsin's Institute for Environmental Research, has shown that a drop in the global average of 1.8° shortens the growing season for crops by two weeks; in addition, the cooler growing days allow less growth. The result is a falloff in crop yields of 27 percent. A drop in the global average of 4.3° would cut crop yields by 54 percent and would effectively wipe out many agricultural regions.
After 1940 world temperatures turned downward, while industry (and fossil-fuel use) grew apace. Apparently things were not so simple; some scientists suggested that there was actually a net removal of CO2 due to expansion of agriculture. Evidently the scientists needed more data. In 1958 Charles D. Keeling, of Scripps Institute of Oceanography, began regular monitorings of CO2 in the atmosphere atop the Hawaiian mountain Mauna Loa, which was far from any industrial center. Keeling 's associates also undertook similar measurements at the South Pole. As the 1960s progressed, other scientists succeeded in devising means to determine past global temperatures, to understand how CO2 would be interchanged with the oceans, and to calculate with better accuracy how an increase in CO2 would lead to a rise in world temperatures.
By the 1970s the time was ripe for important advances. Based on studies of oxygen isotopes in ice cores taken from Camp Century, Greenland, W. Dansgaard and other glaciologists found a record of fluctuations in mean temperatures over past centuries. These fluctuations were quite adequate to account for the observed changes; this meant that human activities had not yet become a dominant influence. The news from Hawaii was less sanguine. Keeling showed that from 1958 to 1976, atmospheric CO2 increased by 5.4 percent, from 314 to 331 parts per million. That would be enough to raise world temperatures above their pre-industrial values by at least half a degree, according to such atmospheric scientists as NASA's Ichtiaque Rasool. Moreover, this CO2 buildup had followed closely the rise in burning of fossil fuels and could be understood if half the man-made CO2 stayed in the atmosphere while the rest dissolved in the oceans. Indeed, a number of oceanographers showed that this occurrence was quite reasonable, though the consensus was that the world's forests also helped by absorbing some of the CO2 in their growth.
With that, anyone reasonably acquainted with world industrial trends could show that by the early decades of the next century, CO2 levels were likely to rise above 500 parts per million, close to double the pre-industrial value. According to the most widely accepted climatic models, the attendant rise in world temperatures would be about 4°, which would make Earth 's climate warmer than at any time in the last thousand years.
If the resultant temperature rise was consistent throughout the planet, we might well say it would be pure delight. The last time global temperatures were even a couple degrees higher than today was around the year 1000, when Viking settlers were able to do farming in what was then the aptly named Greenland. The cited atmospheric models predict increased rainfall with the added CO2, which with the warmer temperatures would mean longer growing seasons, more vigorous growth of crops. The expectation that temperatures would stay at 1940-1950 levels led Soviet planners to seek to make cropland of the "virgin lands," marginal croplands in central Asia, in a project which failed dismally. A few extra degrees could make a lot of difference to the agriculture of the Soviets and of Canada, too. Indeed, to the extent that growing CO2 levels may enhance crop yields, the world's governments would welcome this effect and resist efforts to cut down on their CO2 releases.
That could prove their undoing. If temperate-zone climates were to warm by some 4°, then these same atmospheric models predict that polar temperatures would rise by up to 16°. That could well prove sufficient to change the temperature structure of the oceans, thus causing a major rise in sea level.
The temperate-zone oceans consist of a surface layer of relatively warm water, a zone of intermediate temperatures that decrease with depth, and a deep cold layer. It is this way because at cold polar regions, icy water descends to the ocean bottom and migrates at depth toward the equator. Any warming of the polar regions thus could warm the oceanic abysses as well, which now are only a few degrees above freezing; eventually the whole of the oceans would grow warmer. The oceans contain some sixty times as much CO2 as the atmosphere, and each degree of warming could release enough CO2 to increase the atmospheric content by 3 percent, leading to still further warming.
The syndrome of human-generated CO2, polar warming, deep ocean warming, and release of oceanic CO2 could bring rapid, unplanned changes, which would cause severe global difficulties. Moreover, there are enough fossil fuels available to produce a rise in CO2 levels not merely twofold, but tenfold. This syndrome could well result in that often-predicted and much-feared event, the melting of the polar caps. Depending on how extensive the melting and how strongly it would affect the mile-deep glaciers that cover Greenland and Antarctica, the rise in world sea levels could exceed a hundred feet.
It all could happen quite rapidly, too. It has happened before. The last major advance of the Ice Age glaciers was some seventy thousand years ago. For nearly sixty thousand years the ice sheets endured, a mile deep where Chicago stands today, extending south to the Carolinas, burying much of Europe beneath their massive frigidity. Then about fifteen thousand years ago, the glaciers, those sturdy and interminable institutions, began to melt; and when they did, how quickly they went! As the geologist Cesare Emiliani has noted in a 1975 Science article:
That earlier glacial melting lifted world sea levels by close to three hundred feet. If the sea level were to rise by a foot each year, many seaports and coastal areas could stay dry only by building seawalls and dikes on a massive scale. Many parts of the world might seek to become latter-day versions of Holland, and it is an interesting question how successful they would be. The drama of Noah's Ark could be played out in the flooded streets and avenues of Manhattan.
The situation is even more complex than this and thus potentially even more severe. Until recent years it was believed that a worldwide growth of living plants was serving to take up some of the excess CO2. This belief made it easier for oceanographers to account for the flow of CO2 into the oceans, since it limited the flow to levels consistent with their understanding of the oceans. However, in recent years such biologists as George M. Woodwell, director of the Ecosystems Center at Woods Hole, Massachusetts, have emphasized that the worldwide clearing of forests represents an additional source of CO2. This new source may be as large as that from fossil fuels. Trees chopped down are usually burned or left to decay; in either case there is CO2 release.
This discrepancy has caused a conflict between biologists and oceanographers. The biologists have pointed to much excess CO2 from man's clearing of forests and have noted that the total CO2 production, from forests and fossil fuels combined, far exceeds the increase in atmospheric CO2 as measured by Keeling. They have suggested that the excess winds up in the oceans. The oceanographers have offered much experimental evidence to show that they understand CO2 transport into the oceans and have insisted that in no way could the oceans accept so much excess as the biologists would wish. And while the scientific debates continue, the CO2 buildup in the atmosphere proceeds apace.
The consequences of this debate will affect us all. If the biologists are right, then the sea can absorb more CO2 than is now believed, and it may be a long, long time before there is a climatic change. If the oceanographers are right, the buildup of atmospheric CO2 will continue with increasing speed, and the current rapid clearing of tropical rain forests may make the buildup proceed even faster. Until there is resolution of this issue, there will be no chance that scientists will be able to issue a clear warning of danger, much less that any warning would be heeded.
Without knowing it, humanity has entered into a vast global experiment with consequences that are poorly understood. These consequences could include shifts in patterns of wind and rainfall or of ocean currents such as the Gulf Stream. It is quite possible that humanity will inadvertently cross a critical threshold and trigger a rapid climatic warming. If unpleasant effects arise, they will not be quickly reversed and may not be reversed at all. Animals today generally are adapted to relatively cool conditions, and climatic change could mean vast shifts in Earth's patterns of life. A rise in sea levels could go beyond the capacity of societies to adjust easily.
These changes may take place during the very decades when space colonization could become significant, and it is tempting to imagine how activities in space may alleviate or even remove the climatic effects. To keep the CO2 buildup under control, the world would have to limit its burning of fossil fuels and restrict the clearing of forests. Yet these policies would mean social and economic upheavals virtually as severe as those from the CO2. The best solution would be for the world's peoples voluntarily to adopt new energy sources as replacements for fossil fuels, and this may yet come about.
One of these energy sources could well be the power satellite. It is one way to get energy without CO2, and while it is not the only one, it certainly will see intensive interest. If it proves the least costly and most readily expanded energy source, as it may, then the powersat may sweep all before it.
Space colonies then will have an inevitable distinction indeed, for they will become centers for the building of the next century's valued energy plants. Far from being a matter for speculation, as it is today, space colonization will attract vast resources and efforts. It would be the history of Alaska all over again. At the time of Alaska's purchase (for two cents an acre) in 1867, Secretary of State William Seward was accused of wastefulness for buying "Walrussia," or "Seward's Folly." Time passed, and the day came when the nation came to look to that very land as an important source of oil.
In the decades to come, shortages of oil may delay but will hardly prevent a growing worldwide surge toward industrialization. The worldwide demand for higher living standards is so pervasive, the possible means of obtaining needed energy and resources so numerous that such rising living standards surely will be achieved. A growing accumulation of atmospheric CO2 can only result from increased use of coal, oil shale, and (to the extent available) petroleum, and it is simply wrong to regard this as a bad thing, a form of pollution. What it will also mean will be rising worldwide affluence.
To speak of worldwide affluence may seem a bad joke, for today we are 4.2 billion people, most of them poor. Our tribe increases by some 70 million each year. There is no denying that today poverty is widespread, thoroughgoing, pervasive, and increasing year by year in the number of people it touches. The one thing it is not, or need not be, is interminable.
Worldwide affluence means the growth of a worldwide middle class. The definition of middle class varies from culture to culture even within a given country; thus autos, a virtual necessity even for many poor people in California, can be happily dispensed with at all income levels in Manhattan. Nevertheless, a broad measure of middle-class status would include ownership of autos and telephones and use of electricity and crude oil. Population specialist Nathan Keyfitz, of Harvard, has found that with such a measure the world middle class numbered some 500 million in 1970 and increased to perhaps 600 million by 1975. Significantly, the same index gives a total of only some 200 million in the world middle class in 1950. During those years, 1950 to 1975, world population grew from 2.5 to 4.0 billion, for an average annual increase of 1.9 percent. The average annual growth in the world middle class was 4.5 percent.
If these trends were to persist, then as early as the year 2025 a majority of the world's population, some eleven billion, would enjoy middle-class standards of affluence. It is against this backdrop that one may assess the prospects for China's ambitious program of "Four Modernizations" (of agriculture, defense, industry, science and technology), which aim to bring the standard of living of her billion people to Western levels by the year 2000. The aim is a growth rate of 7 percent per year and the fact that China is self-sufficient in oil will help. By contrast, Japan enjoyed a growth rate of some 15 percent from 1950 to 1973, and since that oil-embargo year still has averaged 8 percent or 9 percent.
The years 1970 to 1973 were unprecedented in economics. Agricultural production rose; the Green Revolution offered increased yields for many crops. Petroleum was so abundant and cheap that even Japan and the nations of central Europe, oil-poor and long accustomed to coal, switched to the new fuel. Resources were ample to support growth both of economies and of populations. Today, of course, the situation is rapidly changing. Rising prices for energy, for agricultural products, and for many industrial raw materials signal increasing pressure by today's people on the available resources. Thus, will the trends of that quarter-century continue; will such advances in worldwide affluence indeed materialize? In Colonies in Space I used the work of Alvin Weinberg to point out that with the important exceptions of hydrocarbons and phosphorus for agriculture, the most extensively used materials exist in extractable quantities which at 1968 rates of use would last for millions of years. This is not to say that today we do rely on the resources that contain these materials in greatest total abundance. On the contrary, we usually rely on resources that furnish needed materials at the lowest cost, even if they can do so for only a few decades. Given time, the economic system is resilient and can substitute common materials for scarce ones, but this replacement does not happen overnight. What is needed is not only invention and innovation, but the huge capital investments that serve to develop new industries to replace old ones.
The long-delayed rise of a U.S. shale oil industry is a case in point. The world's greatest reserves of hydrocarbons are not in Saudi Arabia. They are found in the Green River, Uinta Mountains, and Piceance Creek oil-shale formations of Wyoming, Utah, and Colorado; but as with solar energy, the needed technology and capital have only lately seemed available. There is irony when motorists in these states curse the gasoline situation as they form long lines at the pumps; it is uncomfortably similar to Arthur Clarke's fable of cavemen freezing to death atop a mountain of coal.
As many writers have stated, the most important resource is human ingenuity. It is this resource, far more than any other, which will determine the pace of growth of the world middle class by overcoming limits of existing material supply and opening the prospects for substitutions or replacements. The economist Simon Kuznets of Harvard, a Nobel laureate, has summed up the world's economics: "Lack of resources is not the cause of underdevelopment. It is underdevelopment that is the cause of lack of resources."
With this perspective, power satellites may or may not lead a world advance to prosperity, but they can be very much a part of the work of human inventiveness. It is this inventiveness that may bring new agricultural techniques, better climate forecasts, fusion, new contraceptives, improved electronics, more widespread use of motors in place of human labor or draft animals, more responsive governmental policies, icebergs as a source of fresh water, increasingly influential regional economic groupings of nations, space colonies, and much more.
If space colonies open up as a virtually limitless human milieu, it is quite possible that they will see vast immigrations. People tend to move to wherever their prospects and hopes will be brightest, and the day may come when tens and even hundreds of millions of people live in space. Still, that will probably take several centuries, and it is not clear that rocket transport will ever be relatively less costly than the sea travel that brought America's settlers. In the course of a century of immigration, some thirty million people came to our shores—a total that today is exceeded by five months of growth in today's world population. It will be at the very least a long, long time before a space nation will offer the prospect of siphoning off Earth's growth in numbers.
No, the problem of population, which limits economic growth rates and delays improvements in living standards, probably will be faced and met on this planet. In anticipating a long-term future for humanity, whether on Earth or in space, one of the most fascinating possibilities is that of population shrinkage, not growth; and today's developed nations may show the way.
To achieve zero population growth, the women of a nation must have an average of 2.1 babies each; this is the so-called "replacement fertility." Of these, more will be boys than girls, while some will not live to reproductive age; that is why the figure is 2.1, not 2.0. Since census bureaus deal with births year by year, rather than over the decades of a woman's childbearing years, there is the yearly "fertility rate": the number of children 1,000 women would bear if they had children through all their fertile years at that yearly rate. A fertility rate of 2,100 then is the same as replacement fertility, if kept up for enough years.
In America, the post-World War II years saw the Baby Boom, but the past decade has seen quite a different trend. The fertility rate peaked at 3,724 in 1957, but subsequent years saw it fall sharply. In 1970 it was 2,447; in 1972, 2,025, which for the first time was below replacement level. Since then it has fallen further. It was 1,900 in 1973, about 1,800 in 1978, and still is trending down. According to Charles Westoff, director of Princeton University's Office of Population Research, the rate is likely to go to 1,700.
Since there are a lot of young women in America, our population will keep rising for a while, albeit slowly, despite these low fertility rates. In Europe the situation is quite different. There the fertility rate in a number of countries may reach 1,500 by 1986 and stay there. In 1978 Westoff pointed out that both Germanys, the United Kingdom, Austria, and Luxembourg already were experiencing population declines. In 1979 Lester Brown, president of the Worldwatch Institute, added Belgium and Sweden to the list. He also suggested that by 1985 this roster might grow to include France, Italy, Japan, the Soviet Union—and the United States.
Why should this be? Better contraceptives have helped, but the U.S. fertility rate was between 2,100 and 2,200 during the Depression, long before the Pill. Much more important than contracep¬tives is the will to use them. Throughout the developed world there have been trends for women to receive more education, to marry later and to have the freedom to divorce, to spend at least part of their careers working outside the home, and to control the number and spacing of their babies. All these are powerful influences, which run counter to the traditional role of a wife who marries early and has lots of kids. Instead of motherhood being a woman's prime goal and role, it is increasingly only one of a number of interesting things she may do with her life.
The Baby Boom was actually an upward blip, albeit a significant one, on a 150-year trend to lower U.S. birth rates. In 1820 the birth rate was 55 births per 1,000 of population; by 1900 it was 32, and during the 1920s skidded to 21. During the Baby Boom it jumped up again, peaking at 27, but then fell back. By 1975 it was at an all-time low of 14.8. Still, this rate was not the lowest. In France in 1976 the birth rate was 13.6; in East Germany in 1975, 10.6. Even China apparently had the very low birth rate of 14.0 in 1975.
So it appears that these trends will continue and will touch more and more nations. In undeveloped economies children may be valued as economic assets; they can help with tilling the 238 fields and can provide for the parents in old age. With the growth of cities, the advent of more sophisticated agriculture, the rise in educational levels, children cease to be assets and become economic liabilities. This, plus advances in the status of women, serve as powerful incentives in reducing population growth.
In today's advanced nations, some 30 percent of young women will likely go through their childbearing years without having any children. This means that once the population levels off, it will turn downward with increasing speed; for if 30 percent are childless, to reach the replacement level of 2,100 births per 1,000 women the remaining 70 percent would need three children each. As Charles Westoff has put it (Marriage and Fertility...),
As these new population trends gain strength, it will become evident that many nations have embarked on another vast experiment. This one will test whether it is possible to have both replacement-level fertility and high levels of status and independence for women. It may be instead that even with elaborate pro-natalist programs, it still will prove quite difficult to prevent population declines. After all, baby-making is not only a highly personal choice; it also is par excellence the sort of thing of which a couple may say, "Let John and Marsha do it."
What's more, small families can live better and enjoy greater affluence. The difference between two children and three amounts to a 25 percent gain in income per person, which is more of a rise in living standards than a working man may achieve with ten years of raises. The future then could well be one of limited populations and, in many parts of the world, diminishing numbers of people, but all living better and better.
There is no obvious limit to this. If the world population peaks out at ten billion and thereafter declines at an average of one-half percent per year, the passage of fourteen hundred years will see a reduction to ten million. It may be hard to accept, but the mathematics are plain. And as long as declining populations pose no evident discomfort to people's lives, there will be little pressure to increase the birth rate. By the year 3000, the U.S. population could be down to the levels of a few hundred thousand that prevailed before 1492, but instead of living like Indians, each of these favored few would live at least as well as Jacqueline Onassis.
This may be the world of the space colonies. This world, within which the colonies will flourish and expand, may be one of man-made climatic changes, of shrinking populations (or, in Africa, Asia, and Latin America, populations which are in the process of peaking out), and of a growing affluence produced by the work of human ingenuity. In such a world, powersats and space colonies need not be rejected or dismissed merely because they appear to be far-out ideas; the world will need many far-out ideas to maintain its recent trends toward prosperity. Nor may such space projects be left to languish for want of needed capital or support, for vast flows of capital will come forth for the most promising prospects and the best-founded new programs. The building of powersats and the colonization of space will be weighed on their merits.
A trend to limited or shrinking populations may well mean that the human race, despite a significant reach into space, would still keep Earth as its center. The space colonies might be the new America, but it is worth remembering that this continent has never held more than 7 percent of the world's people, despite centuries of growth and immigration. In his famous 1974 article in Physics Today, "The Colonization of Space," Gerard K. O'Neill of Princeton University pointed out that the resources of the asteroids alone could support twenty thousand times the present world population at very high standards of living. Yet if the colonies follow the precedent of America, they may never support more than a few percent of humanity. In a world that increasingly may emphasize quality of life over quantity in numbers, the colonies could lead the way.
One area in which the colonies can take this lead will be in the introduction and increasing use of robots. The initial use of robots in construction activities will mean that they will be an integral part of life, and colonists will be inclined to find new opportunities to use them. If the population of humans is to shrink while that of robots is to grow, might the day come when they would become the dominant species?
In Chapter 2 I mentioned and then put aside the question: Could silicon-based life grow out of carbon-based life? As the reader may have guessed, what I meant was the origin of an intelligent species manifesting life as we know it, which goes on to invent computers and robots and then loses control of its own inventions. If robots are to proliferate, might the orbiting colonies prove a variation on the theme of monsters from space that take over from humans?
Certainly, computers and robots can be made to superficially mimic life, even intelligent life. However, they lack one essential element, which is life itself.
The basic unit of life is the cell, and one-celled plants and animals are quite common. Under the microscope they swim and move to and fro. They must ceaselessly carry out a metabolism, taking in some substances and excreting others; they continually require energy. They recognize food; they avoid less hospitable surroundings and seek the more hospitable. They can exchange genetic material with others of their kind, through the process known as conjugation, and at length they will fission and reproduce. Theirs is a continual struggle to maintain their molecular complexity, to avoid being broken up into simpler and more stable compounds. Theirs is the law: Grow, or die.
The basic unit of a computer is a transistor or similar circuit element, a simple structure of silicon. It exists in one of two electronic states, depending on the flows of current it has received—and that is all. It conducts no metabolism. It seeks no food, nor does it seek electrons. It can exist amid rapid switchings between states or in quiescence—it is ambivalent. It need do nothing to prevent death or decay, for it is already in a simple chemical state, which it can sustain throughout the ages.
In ages past men erected statues of stone that were cunningly wrought, and, carried away by the skill of their work, declared that the statues were gods, with the power and influence of a living king. The art of building computers and robots is skillful indeed, yet it does not alter the nature of their materials or change them from nonlife to life. A device like the Speak and Spell is indeed a wonder; it is akin to teaching a stone to speak. Yet the stone remains a stone. It is not a man, nor is it a new form of life.
Yet if it is not through robots that space colonies may devise a next step beyond man, still in these colonies the successor to H. sapiens indeed could be created. The colonies will be quite diverse, and it will be a common thing for specialized groups of people, with distinct customs and interests, to go off to the far reaches of the asteroid belt and establish space colonies of their own. Perhaps among these groups there will be some dedicated to developing an advanced or improved type of human being.
To say that this idea is unpopular, that it conjures up visions of every horror from Frankenstein's monster to Nazi experiments, is to explain why the advocates of this goal might seek to live and work far from the broader community of Earth-people. The human culture will tolerate and even encourage much. Few customs or codes of law will appear unacceptable, and differences in people's appearances will carry less and less weight. What we have no experience with in modern times, what we have not faced since the Cro-Magnon gained dominance over the earlier Neanderthalers, is for an established human stock to face a genetically superior species.
By "genetically superior" I have in mind the Darwinian concept of competition between species, rather than any cultural patterns. As to what endowments, what innate ways of thinking, what physical changes could constitute transhumanity—that is a hard matter to address. It is difficult to say what the limits are to cultural changes, or to what degree such changes could fail to leave humanity equipped to meet future challenges. Yet we know that people have all too frequently suffered from mass delusion and self-delusion, from tendencies to be carried away by their emotions at the expense of their reason, and from difficulty in adopting critical or skeptical modes of thought or in weighing present desires against the more significant needs of the future. Are these merely cultural shortcomings that could be overcome with better forms of education? Or will some group of experimenters link these features to structures of the human brain, which can then be rewired?
The question of human conformity, the urge to follow and belong to a group, may be important here. Harvard's Edward 0. Wilson, founder of the science of sociobiology, has written of "conformist genes," suggesting that conformist tendencies are inherited, not learned. Paul MacLean of the National Institutes of Mental Health, whose work formed much of the basis for Carl Sagan 's The Dragons of Eden, has traced the roots of conformist behavior to the deep-seated structures of the brain known as the R-complex. He has pointed out that Einstein was a nonconformist and a loner and has suggested that "some individuals may become creative because of a constitutional incapacity for imitation...a defect of the nervous system that might interfere with the intercommunicative [group-feeling] process. " Such a person could talk with members of a group, and join in its activities, yet would not necessarily feel himself to be a part of that group. A genetically superior humanity then might simply be one in which the R-complex has been modified or weakened. This could come through editing the genetic code, which contains the specifications for a human being.
I do not know whether anyone will ever determine the complete sequence of the nucleotide bases that serve to specify a human being, but it may happen. For several years the means have existed to do precisely that, at least in principle. All living beings have their nature coded in long molecules of the genetic material, DNA. The code consists of sequences of the molecules adenine, thymine, cytosine and guanine, denoted A, T, C, G; any triplet of these so-called nucleotide bases then codes for or corresponds to a specific amino acid. A complete nucleotide sequence is a long string of these bases. It is like an encyclopedia of words all run together, written with an alphabet of four letters.
Thus far, genetic codes have been worked out only for such simple creatures as viruses. For instance, Frederick Sanger and his associates at Cambridge University have found that a bacterial virus designated øx174 has a nucleotide sequence of 5,375 bases that are grouped into nine genes, which in turn code for the amino acid sequences of nine different proteins. The complete nucleotide sequence for øx174 fills a page of ordinary type. A typical bacterium would need two thousand such pages to represent its code; a man would need a million pages.
The working-out of such sequences has involved techniques closely allied to those that actually serve in the manipulation of genes and the revising or editing of genetic codes. It is not appropriate here to go into the controversy that these techniques have spawned in recent years. However, these methods permit the extraction of sequences of DNA from one species and their transplantation or splicing into the DNA sequence of an entirely different species. These methods, known collectively as "recombinant DNA," have allowed biologists to create entirely new forms of bacterial life. Such bacteria have already been successfully designed to manufacture the brain hormone somatostatin, and there recently have been major advances in transplanting rat genes into bacteria so as to cause them to produce insulin.
It is too early to say what will be the ultimate impact of this control over the ultimate sources of life. For now, we must imagine that these techniques, or their even more sophisticated descendants, have allowed a group of researchers in a space colony to evolve a genetic sequence which, when incorporated in a fertilized human ovum, leads to the first of the species Homo transsapiens. In that distant colony, guided by the researchers, the transhumans could then assemble their gene combinations and increase in number.
And when they venture forth to face a solar system dominated by H. sapiens, what response will they find? Will they be greeted in friendship, welcomed to an honored place in the family of man? Or will they meet fear and hostility, and the certainty that however few their number, they will be regarded with the awe and fear with which the Neanderthalers must have faced the Cro-Magnon?
If they are to be treated as outsiders, relegated to remote regions of the Solar System rather than be granted the opportunity to make good their competitive advantage, then these transhumans might emigrate rather than accept such restrictions. They could not emigrate to any part of Earth, of course, nor to any other region of nearby space. Instead, their port of call would be—the stars.
It is no new thing to write of star flight, star colonization; what has not been so evident has been a motive. It cannot be commerce, nor population pressure, or even wanderlust or adventure. To speak of starfarers as adventurers is in a sense a contradiction in terms. They would have to spend decades or centuries under disciplined restrictions while en route before their descendants could establish their settlements. And in all but a vanishingly small number of cases, the settlements would be space colonies built from asteroidal materials, differing only insubstantially from what they might have built in unsettled regions of our own Solar System.
Yet what if the motivation is not adventure, but opportunity? What if the emigration is a necessity, if the starfarers are to avoid hostility or severe restrictions on their actions? On Earth oppressed peoples have commonly sought freedom in new lands beyond the seas. This oppression has stemmed from cultural differences; how much more significant may the differences be if they are not cultural, but genetic.
Still, the question of a motive is one that may resolve itself in time. The idea of transhumanity achieved through recombinant DNA is no more than a speculation; far more so is the notion of transhumans becoming starfarers in order to escape persecution. After all, recombinant DNA today is no more than the latest technique in the human quest for knowledge. In the early 1800s the latest technique was electricity, which Galvani had used to cause frogs' legs to twitch. This was the discovery that inspired Mary Wollestonecraft Shelley to conceive the legend of a new form of human invented by her fictional medical student, Dr. Frankenstein. To write of transhumanity fleeing to stellar space may be simply a fable, a suggestion of the character of a world that could send ships to the stars.
In the end, we can only say this: If space colonization goes forward, in time people will have both the ability and the means to seek the stars. We have been in such situations before, and we have seldom disdained to take advantage of the new opportunities. It has lately been fashionable to say that all we need is on Earth, that there is no reason save mere vainglory to venture into space. The whole of this book argues against this. In the future it may be said that all we need will be in the Solar System, that there will be no reason to seek the stars. Perhaps that view will in time also pass away, even if for reasons that today are obscure.
We do know that if humanity persists and endures, in time we will come face to face with the evolution of our sun. In a few billion years its slow brightening will speed up as it swells into a red giant. Earth then will be uninhabitable, as will the inner regions of the Solar System. Yet there will be other and more clement stars to which our descendants may wish to migrate. Certainly, a society that has developed space flight and space colonization will have the advantage of never thereafter having to stand hostage to fortune.
There still is the question posed in the last two chapters: Are we alone? The answer is there to be found. It exists somewhere out among the stars, and it will be our spacefaring descendants who will learn it.
Descendants of space colonists, heirs to a world deeply influenced by these colonizations, will be touched and shaped by their milieu. It is that milieu, what the poet Diane Ackerman has called the cosmic overwhelm, which even today looms as one that will increasingly occupy our attentions in the decades, the centuries ahead. It will give terror and delight, loneliness and fond companionship, reverence and awe. It will be a challenge to face, a source of hope and wonder, a highway, a sea—yes, and a place of death.
There are people of islands and seacoasts, of rocky peninsulas where the surf murmers at night amid the salt spray. Their lives, their beliefs, their work all have entered our common heritage. The sea has governed and shaped their ways, fashioned their histories as surely as it has cut the ocean cliffs beside which they fish. Their thoughts and experiences have become part of our culture, and we are the richer for it.
So it will be with that vaster sea, that overwhelm, and with those who will build their homes afar, live their lives in the void. It will be thus with those adventurous ones, those creators of new things, those people of the future, who will venture toward distant suns.