Extraterrestrial Civilizations - Isaac Asimov [124]
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