The only adverse environmental conditions that would affect the underground world would be volcanoes, earthquakes, and meteoric impacts. However, we know where volcanoes exist and where earthquakes are common and might avoid those areas. And perhaps we will have a space patrol to destroy any meteoric objects likely to bring them uncomfortably close.
Second, local time would no longer be important. On the surface, the tyranny of day and night cannot be avoided, and when it is morning in one place, it is noon in another, evening in still another and midnight in yet another. The rhythm of human life is therefore out of phase. Underground, where artificial light will determine the day, we can if we wish make a uniform time the planet over. This would certainly simplify global cooperation and would eliminate jet lag. (If a global day and global night turn out to have serious deficiencies, any other system can be set up. The point is it will be our system and not one forced on us by the accident of Earth’s rotation.)
Third, the ecological structure could be stabilized. Right now, with humanity on the planetary surface, we encumber the Earth. Our enormous numbers take up room, as do all the structures we build to house ourselves and our machines, to make possible our transportation and communication, to offer ourselves rest and recreation. All these things distort the wild, depriving many species of plants and animals of their natural habitat-and sometimes, involuntarily, favoring a few, such as rats and roaches.
If humanity and its structures are removed below ground -well below the level of the natural world of the burrowing animals-Man would still occupy the surface with his farms, his forestry, his observation towers, his air terminals and so on, but the extent of that occupation would be enormously decreased. Indeed, as one imagines the underground world becoming increasingly elaborate, one can visualize much of the food supply eventually deriving from soilless crops grown in artificially illuminated areas underground. The Earth’s surface might be increasingly turned over to park and to wilderness, maintained at ecological stability.
Nor would we be depriving ourselves of nature. Indeed, it would be closer. It might seem that to withdraw underground is to withdraw from the natural world, but would that be so? Would the withdrawal be more complete than it is now, when so many people work in city buildings that are often windowless and artificially conditioned? Even where there are windows, what is the prospect one views (if one bothers to), but sun, sky, and buildings to the horizon-plus some limited greenery?
And to get away from the city now? To reach the real countryside? One must travel horizontally for miles and miles, first across city pavements and then across suburban sprawls. And the countryside we would be viewing would be steadily retreating and steadily undergoing damage.
In the underground world, we might have areas of greenery, too, even parks-and tropical growth in greenhouses. But we don’t have to depend on these makeshift attempts, comforting though they may be to many. We need only go straight up, a mere couple of hundred yards above the level of “Main Street, Underground” and-there you are.
The surface you would visit would be nature-perhaps tamer than it might be, but relatively unspoiled. The surface would have to be protected from too frequent, or too intense, or too careless visiting, but however carefully restricted the upward trips might be the chances are that the dwellers in the underground world would see more of the natural world, under ecologically sounder conditions, than dwellers of surface cities do today.
I am interested to see, by the way, that the notion of underground living has begun to seem more realistic in the decades since I wrote The Caves of Steel. For instance, many cities in the more northerly latitudes (where cold weather, ice, and snow inhibit shopping by making it unpleasant) are building underground shopping malls-more and more elaborate, more and more self-contained, more and more like my own imagined world.
However, my imagination is not the only one the world possesses. Here we have Refuge, by Rob Chilson, in which my underground city of the future is explored by another science-fiction writer skilled in his craft, who has taken my underground cities as the starting point for his own.
Chapter 1. Kappa Whale
The stars gave no light. Derec crawled slowly along the ship’s hull, peering intently through his helmet at the silvery metal. The ship was below him, or beside him, depending entirely on how one looked at it. He preferred to think of it as “beside”-he felt less as if he might fall that way.
To his left, to his right, “above” and “below” him, was nothing. But space was nothing new to Derec, whose memories began only a few months ago in a space capsule-a lifepod, in fact. At the moment he had no time for memories of the pod, of the ice asteroid, or of capture by the nonhuman pirate Aranimas. He was concentrating on swimming.
“I’m at the strut,” he announced.
“Good,” said Ariel, her voice booming in his helmet.
Derec hadn’t time to turn his radio down, nor did he wish to let go just yet. His crawl along the hull, helped by the electromagnets in knees and palms, had been slow, but inexorable. When he seized the strut, his hand stopped but his body continued on past, like a swimmer carried by a wave. A wave.()f inertia.
Gripping the strut, he found himself slowly swinging around it like a flag, facing back the way he’d come. He had realized immediately that he shouldn’t have grabbed the strut, but didn’t compound his error by trying to undo it. He let the swing take him, absorbed his momentum with his arm-it creaked painfully-and came to a stop.
A robot, advancing in its tracks, arrested itself on the other side of the strut in the proper way: a hand braced against it, the arm soaking up the momentum like a spring. Being a robot, he had no fear of sprained wrists, the most common injuries in free-fall.
The robot, Mandelbrot, paused courteously while Derec resolved his entanglement with the strut. Derec gripped it with both hands and bent one elbow while keeping the other straight. His body revolved slowly around the bent arm until he had reversed himself. Placing his foot against the strut, he tippy-toed away from it, letting go, uncoiling, and reaching out for the hull.
For a moment Derec was in free, dreamy flight, not touching the ship; then his palms touched down, the magnets clicking against it as he turned on crawlpower. He slid forward on hands and forearms while his inertia wave was absorbed by the “beach” of the ship’s hull. His chest and belly and finally his knees touched down painfully, to slide scraping along.
“Frost!” said Ariel. “What are you doing, sawing the hull in half?”
Derec didn’t reply. Not letting all his momentum be absorbed, he came quickly to hands and knees, reaching and pulling at the hull. The magnets were computer controlled and clicked on and off alternately in the crawl pattern.
In a few seconds he braked and all the magnets went on. He skittered slowly to a stop. Mandelbrot joined him in a similar fashion and looked at the hull, then moved aside.
“Right, we’re at the hatch,” said Derec. “It doesn’t look like we’ll need any tools to get in; just a matter of turning inset screws.”
There were two slits in the hull, each in a small circle. The circles were at one edge of a square outline-the hatch. Derec stuck two fingers in one of the slits, Mandelbrot copying his motion at the other side, and they twisted the circles clockwise. There was a pop, and the hatch rode free.
“Got it open,” Derec said.
That was a little premature. He would have to stand up on the hull to raise the hatch, or else move around. But before he could make up his mind, Mandelbrot reinserted his fingers into one of the slits and pulled. The hatch came free easily. Mandelbrot bent his arm like a rope, heaving the hatch up over his head, put up his other arm, and the hatch stood out from the hull.