Extraterrestrial civiliz.., p.28
Extraterrestrial Civilizations, page 28
Such space settlements would not carry supplies of food and oxygen in the ordinary sense. They would be in functioning ecological balance that could maintain itself indefinitely, given a secure energy source and the replacement of minimal material. Nor would they carry a crew in the ordinary sense of the word. They would be inhabited by tens of thousands, perhaps even by tens of millions, to whom the settlement would be their planet.
The gradual exploration of the Solar system by the settlers and the gradual extension of the range of the settlements to the asteroid belt and beyond would surely weaken the emotional bonds that would hold the settlers to the ancestral Earth and even to the Sun.
The mere fact that to settlers in the asteroid belt and beyond the Sun will be so much farther off and so much smaller will decrease its importance. The fact that it will become harder to use as an energy source as distance increases will encourage the shift to hydrogen fusion, all the more so since there are ample hydrogen supplies in the Solar system beyond Mars. That, in turn, will make the settlements still less dependent on the Sun.
Furthermore, the farther a settlement moves from the Sun, the easier it can develop a speed capable of taking it out of the Solar system altogether.
Eventually, some space colony, seeing no value in circling round and round the Sun forever, will make use of some advanced propulsion system based on hydrogen fusion to break out of orbit and to carry its structure, its content of soil, water, air, plants, animals, and people out into the unknown.
Why?
Why not?
For the interest of it, perhaps. For seeing what lies beyond the horizon. For the curiosity and drive that has been extending the range of humanity since it came into being, sending bands of people trekking across continents even before civilization began, and now driving them to the Moon and beyond.
There might also be the pressure of mounting population. With ever more space settlements being constructed, there will be increasing pressure on hydrogen supplies, increasing impatience with the growing complexity of intersettlement relationships.
Besides, the trauma of change would be minimal. The settlers would not be leaving home—they would be taking home with them. Except for the fact that the Sun would be shrinking in apparent size and that radio contact with other settlements would become steadily more difficult to maintain (until both Sun and radio contact disappear altogether), there would be no important difference to the people inside the settlement as a result of the changeover from endless circling about the Sun to endless forward movement in the Universe at large.
Nor need the settlers necessarily fear the slow loss of resources through imperfect cycling, or the consumption of their hydrogen fuel. Once a space settlement becomes a free-world, bound to no star, it could find fuel here and there in the Universe.
It might, for instance, work its way through the comet cloud at the very rim of the Solar system, watching for one of the 100 billion comets present there in its native form as a small body of frozen ices. Even as a “small body,” of course, it is a few kilometers in diameter and would contain enough carbon, hydrogen, nitrogen, and oxygen to supply any loss of volatiles through imperfect cycling for a long time and supply enough hydrogen for fuel for an equally long time. (After all, the free-world will not be accelerating or decelerating very often or very much. For the most part it will be coasting.)
When a comet is found, it may be picked up and placed in tow to serve as a longtime source of material and energy. Given time, and the free-world will have nothing in greater profusion than time, a string of them can be picked up.
And the Universe may not be empty after the comet cloud is left behind. Other stars will have comet clouds surrounding them and there may well be occasional bodies totally independent of stars.
Such a voyage avoids all the difficulties we mentioned earlier.
The free-world will be moving slowly so that there will be none of the difficulties of gas resistance and collision, and no energy requirements for extensive accelerations and decelerations. Those on the free-world need be neither immortal nor frozen; they can live normal lives as we do on an extensive world with many people and with Earthlike scenery and a centrifugal effect that produces an Earthlike gravity. Sunlight will have to be artificial, but that can be lived with.
What’s more, the free-world will not have been built and invested in by the people of Earth. It will have been built by space settlers, much in the way that American cities were built by Americans and not by the European nations from which the Americans or their ancestors may have come. That means the free-world will not be dependent upon Earth’s willingness to invest.
Nor will the people on the free-world be inhibited by the thought that their children and their children’s children would pass their entire lives “on board ship”—that is what they would have done in any case. Nor will the free-world people be inhibited by the thought that when they return to Earth thousands or millions of years will have passed. It will very likely never occur to them that they need return to Earth at all.
Perhaps many settlements will convert themselves into free-worlds. The Solar system, having taken 4.6 billion years to develop a species intelligent enough to build a technological civilization capable of constructing space settlements, may finally “go to seed.” It may release free-worlds wandering off in all directions, each carrying its load of humanity in ecological balance with other forms of life.
It may even be that the home world, Earth, will in the long run have significance on a cosmic scale only as the source of the free-worlds. It may continue to serve as a source until such time as, for one reason or another, its civilization runs down, falls into decadence, and comes to an end altogether. The space settlements that do not choose to leave the Solar system may also shrivel and decay, and only the free-worlds will carry on a developing and vital humanity.
Eventually, after a lapse of many generations, a particular free-world may approach a star. It would probably not be an accident that it does so. Undoubtedly, the free-world’s astronomers would study all stars within so many light-years’ distance and suggest an approach to one that is particularly interesting. They might in this way study white dwarfs, neutron stars, black holes, red giants, Cepheid variables, and so on—all from a careful, safe distance.
They may also favor approaching stars that are Sunlike in order to investigate (with some nostalgia, perhaps) the chances of a civilization in existence there. It could well be that there will be no impulse whatever to land on an Earthlike planet and to subject themselves to the long forgotten and by now possibly repulsive way of life on the outside of a world. On such an outside, the cycling system would be so large it could not be controlled, the weather would be a tissue of discomfort and vagaries, and the unselected wildlife would be annoying.
If there were small worlds at a distance from the star, at a sufficiently great distance to have icy materials as well as metals and rock—an asteroid belt would be ideal—then it might be time to build a new space settlement from scratch, abandoning the old free-world, which, despite all repairs, might by then be rather battered. (It would also be an opportunity to introduce new designs and technological advances from the hull in.)
There might well be an overwhelming temptation to linger a while, to build settlement after settlement in the new asteroid belt.
The advantages to this are obvious. During all the long years the free-world has wandered through space, it will have had to maintain a rigid population control. Now there will be a chance to expand population with wild abandon.
Again, through all the long years, the free-world, while much larger than what we would ordinarily think of as a space vessel, would be small enough to make it necessary to enforce a certain uniformity of culture and way of life. The building of numerous space settlements over a period of centuries in an asteroid belt would allow the establishment of widely different cultures.
And, of course, the new space settlements would eventually go to seed and move outward as a new generation of free-worlds.
We might almost imagine civilizations as existing in two alternating forms: a motile, population-controlled form as free-worlds drifting through space; and a sessile, population-expanding form as space settlements about a star.
Each free-world as it drifts through space eventually loses all contact with its home base, with space settlements, with other free-worlds. It becomes a lonely, self-contained culture that develops a literature of its own, as well as art forms, philosophy, science, and customs, with some Earth culture as a distant base, of course . Every other free-world does the same and no one of them is likely to duplicate the culture of another at all closely. And with each settlement in a new Solar system and eventual breakout, a new explosion of difference would result.
Such cultural variations could produce an infinite richness to humanity as a whole, a richness that could only be faintly hinted at if humanity were confined to the Solar system forever.
Different free-world cultures might have a chance to interact when the paths of two of them intersected.
Each would be detected by the other from a long distance, we might imagine, and the approach would be a time of great excitement on each. The meeting would surely involve a ritual of incomparable importance; there would be no flashby with a hail-and-farewell.* Each, after all, would have compiled its own records, which it could now make available to the other. There would be descriptions by each of sectors of space never visited by the other. New scientific theories and novel interpretations of old ones would be expounded. Differing philosophies and ways of life would be discussed. Literature, works of art, material artifacts, and technological devices would be exchanged.
There would also be the opportunity for a cross-flow of genes. Any exchange of population (either temporary or permanent) might be the major accomplishment of any such meeting. Such an exchange might improve the biological vigor of both populations.
To be sure, in the course of the long separation, enough mutation might have taken place to make the two populations mutually infertile. They might have evolved into separate species, but even so, intellectual cross-fertilization may be possible (provided always that the inevitable language difficulty is overcome, for even if two free-worlds had begun with the same language, these would have developed separately into widely different dialects).
In this way, humanity would become no longer a creature of Earth or of the Solar system, but would belong to the whole Universe, drifting outward, ever outward, forming a variety of related species, until such time as the Universe finally came to an enormously slow end and, through one route or another, could no longer support life anywhere within itself.
But what about the extraterrestrial intelligences? Assuming that they do not make use of any dream technologies we cannot even imagine at present, they too may have followed a development that makes the free-worlds a practical way (perhaps the only practical way) of sending living organisms through interstellar space.
Free-worlds may thus arise from thousands of different planetary sources, and some of them may have been moving through space, into and out of the asteroid belts of this star and that, for billions of years.
It may be that if extraterrestrial civilizations have visited us, it has been in the form of free-worlds. And if so, it may be that they have not visited Earth (in which their interest might be limited), but our asteroid belt.
It may be that when our space settlements move out into the asteroid belt we will find ourselves preempted; or perhaps find evidence that free-worlds have been there in the past and have long since gone.* Or it may be that free-worlds, on principle, avoid Sunlike stars with habitable planets. After all, for free-world purposes almost any star would do. A star might be a short-lived giant, but the free-world can stay far enough away to avoid the radiation and might not need more than, say, a century or two to build new starships out of what planetary material is available at such a distance. Even the least long lived star would last many times that period. Or (much more likely) a star might be pigmyish and cool, but the free-world would not need it for energy, just for the planetary bodies circling it.
If many civilizations adopt that technique, it may well be that some human free-world, dropping down toward some planetary system, will find it already preempted by other free-worlds that are nonhuman.
Surely by that point in history, it will be understood that it is the nature of the mind that makes individuals kin, and that the differences in shape, form, and manner are altogether trivial.
It may be that as the human free-worlds start moving outward, they will find themselves part of a vast brotherhood of intelligence; part of the complex of innumerable routes by which the Universe has evolved in order to become capable of understanding itself.
And it may be that in combination, humanity and all the extraterrestrial civilizations can advance farther and faster than any one of them could alone. If there is any chance of defeating what we now see as the laws of nature and of bending the entire Universe to the will of the intelligences it has given rise to, then it will be in combined effort that the greatest chance of success will arise.
* There is one somewhat more hopeful aspect of such a trip that I am omitting now, but that I will come back to later.
*The speed-of-light limit exists for tachyons as well as for particles with ordinary mass (tardyons) but in the case of the former, the limit is a floor rather than a ceiling. Particles with zero mass (or luxons from a Latin word for light) go just at the speed of light, or right at the limit that serves as a boundary, a “luxon wall” between our own tardyon Universe and the ultrafast tachyon Universe.
† In science fiction stories it has long been customary to get round the speed-of-light barrier by making use or some aspect of the Universe in which the barrier no longer exists. The aspect is called hyperspace or subspace, but whatever the word the imagined properties are those of the tachyonic Universe.
*For 25 years, physicists accepted the existence of the neutrino even though it had never been detected, because that existence was necessary to explain observed phenomena. Right now, physicists accept the existence of particles called quarks though they have never been detected, because that existence is necessary to explain observed phenomena. There are no observed phenomena that require the existence of tachyons, however, only the manipulation of equations.
* If a photonic drive were possible, the rate of time passage to people experiencing the drive would be zero. All trips, even to the very edge of the Universe, would seem to take place in an instant. That is why, fast as time dilatation makes astronauts think they are going, they can never beat a ray of light. It may take them only 60 years to reach the Andromeda Galaxy, but when they get there they will find that a light ray would have reached the Andromeda Galaxy efore they did.
* It is easy to speculate that those UFOs that are not hoaxes or mistakes (assuming there are any that don’t fall into one category or the other) are probes, rather than actual extraterrestrial spaceships piloted by living organisms. That is not inconceivable, but, on the other hand, there is no reasonable evidence in favor of this notion. Not yet For that matter, it might well be that the probes have outlived their particular civilization and are sending back messages uselessly.
*Lyman Spitzer suggested such generations-long voyages in 1951, and the science fiction writer Robert A. Heinlein wrote a novelette called “Universe” on this theme in 1941
* It is conceivable that particular free-worlds might be isolationist, fearful or suspicious of other free-worlds, and might choose to veer away from the approach of another. Surely this would not happen often, however. I have better hopes of the curiosity of intelligent creatures
* Those with a more romantic imagination might even suggest that there was an intact planet in the orbit between those of Mars and Jupiter; that a free-world dismantled it in order to build numerous space settlements over a long period of time; and that the asteroid belt is the remnant they left behind.
CHAPTER 13
Messages
SENDING
We have concluded, then, that there may well be over 500,000 civilizations in the Galaxy, but that the only way any of them are likely to emerge from their planetary systems is by interstellar probes or in the form of free-worlds.
There is nothing compelling about either emergence. The vast majority of civilizations, conceivably all of them, may simply remain in their own planetary systems. Any interstellar probes that are sent out may be devices not designed to land on habitable planets but to confine themselves to observations and reports from space. Any free-worlds that may come our way might be more interested in material and energy with which to maintain themselves than in involvement with a sedentary civilization.
In this way, we can rationalize the apparent paradox that while the Galaxy may be rich in civilizations we remain unaware of them.
But what ought we to do in that case?
The simplest answer and the one that involves the least trouble is to do nothing at all. If extraterrestrial civilizations can’t or won’t reach us, we could just go about our own business. Certainly we have enough troubles of our own to occupy us.
The second possibility is to send out some sort of message in order to make contact. Even if an extraterrestrial civilization can’t reach us, or we them, we can perhaps establish communication across space; even if it is only the message: “We are here. Are you there?”
This is such a normal impulse that back in the nineteenth century, when people were still speculating concerning life on other worlds in the Solar system and almost taking it for granted that there would be civilizations even on the Moon, there were suggestions for methods of communication.
The German mathematician Karl Friedrich Gauss (1777–1855) once suggested that lanes of forest be planted on the steppes of central Asia in the form of a gigantic right triangle with squares on each side. Within the triangle and squares, grain would be planted to darken the shapes with a uniform color. A civilization on the Moon or Mars, for instance, closely studying the surface of the Earth, might see this clear display of the Pythagorean theorem and would conclude at once that there was intelligence on Earth.
