Extraterrestrial Civilizations (36 page)

It might well be necessary, then, to strike some middle ground, and send out probes containing devices elaborate enough to send back as much useful and interesting information as possible, but simple enough to endure through the ages. It seems obvious, though, that this middle ground will result in ships being piloted by devices far less intelligent than human beings.

This, too, may be the answer to the puzzle of why we have not been visited by other civilizations. Perhaps we have been; but not by living organisms. Perhaps probes have passed through our Solar system and have sent messages back on the nature and properties of the Sun and its planets, and, specifically, on the fact that a habitable planet exists in the system. If one has passed recently enough, it might have reported a burgeoning civilization.

Of course, we can’t say how often a probe may have passed through, or when the last probe passed, or whether all the probes have belonged to some one particular civilization.
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A conservative view of the possibilities of interstellar travel has made it seem that there is no practical way of sending intelligent organisms from star to star and that the best way would be the use of automatic probes.

So far, however, we have made the assumption that a crew of
astronauts must complete a round-trip voyage to the stars in the space of a human lifetime—either by going faster than light, by experiencing time dilatations, by possessing extended lifetimes, or by the use of deep freezing. Every such device seems impractical.

But then, what if we abandon the assumption and do not require a round-trip in a single lifetime?

Suppose we design a ship that will coast to Alpha Centauri and take centuries to make the trip. Suppose we do not expect the astronauts to be immortal or frozen, but to live normal lifetimes in the normal manner.

Naturally, they will die long before the voyage is completed. However, astronauts of both sexes are on board, and children are born to them, and these carry on—and their children do the same— and their children—for many generations until the destination is reached
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An elaborate life-support system is still needed, but the problem of keeping the astronauts occupied and unbored may be solved. Having children helps pass the time. Deaths and births will bring about a steady change in personnel and remove the boredom implicit in a long, long period of the same old faces. Then, too, youngsters born on the ship will know no other existence (at least firsthand) and presumably will not be bored.

On the other hand, is any trip worth that? Will there be volunteers who will not only be willing to spend the rest of their lives on board ship, but who will be willing to condemn their children and their children’s children to a total life, from birth to death, on board ship? And will the people on Earth be willing to invest in a tremendously expensive project where any benefits to be derived may come only to their descendants 1,000 years hence?

The answer to these questions might be an obvious “No!”. In fact, the average person might be so horrified at the thought as to feel that merely to ask the question is not quite sane.

Yet that might be only because all through this chapter I have been (without quite saying so) assuming that the space vessels undertaking the long trip to the stars are what we ordinarily think of as
“ships”—like a huge ocean liner, or like the Starship
Enterprise
on the television show “Star Trek.”

As long as we deal with such ships, the objections to a generations-long voyage are difficult, perhaps impossible, to counter—but must we deal with them?

At the end of the previous chapter, I had envisaged a Solar system dotted with space settlements—settlements large enough to constitute worldlike communities in themselves.

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.
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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).