Two hours passed, and then two hours more.
We hardly spoke. We sat or stood or sprawled around the great room, puzzled, ill at ease, off guard, baffled into a state of total spinlessness. This episode had taken on all the qualities of a dream: our floating descent, the jostling and pinching given us by the towering robots, our inability to communicate with anyone, the eerie silence, the strangeness of the city, the unreality of this bare cavernous room in which we now found ourselves… prisoners.
Conversation, such as it was, tended to be made up mostly of phrases like:
“Where are we?”
“What does it all mean?”
“How long will they keep us here?”
“Where are the High Ones?”
“Are there any High Ones?”
“Why doesn’t Dihn Ruuu come back?”
“Whose pocket are we in?”
“What’s the whole giboo about?”
Since we had no answers to any of these questions, conversations that began with them tended to be rather brief. By the end of the second hour we had exhausted most immediate themes of this sort and had lapsed into silence all around. Mirrik and Kelly, as usual, were fairly cheerful; Dr. Horkkk sat by himself in a kind of black meditation, all his legs tightly crossed; Pilazinool unscrewed limbs; Dr. Schein wore a frown that deepened and deepened, as though he were having a great many second thoughts all at once; Leroy Chang skulked; Saul Shahmoon seemed to be asleep, possibly dreaming about the postage stamps of Mc-Burney IV; Nick Ludwig paced like a caged beast; Jan and I sat close together, and occasionally one of us flashed a quick nervous grin at the other. We tried not to show our fear; but, after all, this was no dream.
In the third hour we began to wonder when, if ever, the robots planned to let us out. Or feed us. We had a couple of days’ supply of food tablets, but for all we knew we’d be left here two or three months before anyone considered our needs. We had hardly any supply of water. There weren’t any hygienic facilities in here either.
It was the longest afternoon of my life, I think. Here we were in the midst of an incredible city of an ancient civilization — and unable to see a thing, unsure of what was in store.
Finally a place in the wall below one of the stripe-and-dot panels began to swell and pucker; it popped open and Dihn Ruuu stepped through. I could see a couple of the other robots lurking just beyond the opening. Dihn Ruuu moved slowly to the center of the room and swiveled to scan us all.
“The Mirt Korp Ahm,” the robot announced solemnly, “no longer inhabit the present planet. I have learned that this outpost was abandoned by them 84,005,675 years ago, and is currently occupied only by the Dihn Ruuu, that is to say, the Machines To Serve.”
The calm words, delivered in that weird metallic imitation of my own voice, hit us with tremendous impact.
We weren’t amazed to find that there were no High Ones here, just a population of self-sufficient, virtually immortal robots. But to learn that the High Ones had abandoned McBurney IV only some eighty-four million years ago — !
Funny how your perspective changes. On Earth eighty-four million years ago the dinosaurs still went stumbling around, and the only mammals that existed were little ratty things with long noses and sharp teeth. Nor had intelligent life evolved on any of the other planets of our galaxy that currently have it, such as Shilamak, Dinamon, or Thhh. So by any human perspective, eighty-four million years ago is pre-pre-pre-pre-historic.
Yet I said only eighty-four million years. And I wasn’t jesting.
Up to this point all archaeological evidence had indicated, as I’m sure I’ve told you, that the High Ones had mysteriously disappeared from our galaxy 850 million years ago. No trace of them more recent than that had ever been found. On that scale, eighty-four million years ago was practically last week. With one brief statement Dihn Ruuu had lopped away 90 percent of the time-span since the vanishing of the High Ones.
The implications of the robot’s statement staggered us. Seemingly we would have to rethink our entire outlook on the High Ones and their place in the sequence of time. A dozen questions jiggled my brain at once, and it must have been the same for everyone else. But before we could get anything out, Dihn Ruuu iced us on all wavelengths with a far more sposhing statement.
Like a college professor reading off routine announcements at the beginning of class, Dihn Ruuu went on, “It is with great pleasure that I state that the home world of the Mirt Korp Ahm does in fact still exist, and neither it nor its star have been destroyed, despite the impossibility of locating them that I experienced. According to communications received on this planet 13,595,486 years ago, the Mirt Korp Ahm embarked on a project at that time for the transformation of their home system into an enclosed sphere permitting full utilization of the solar energy. An uninhabited planet of the system was used as the source of mass for this project. The enterprise was successfully completed within a period of 150 years after receipt of first notice here. Thereafter, naturally, the home star of the Mirt Korp Ahm ceased to be detectible by conventional optical means.”
I pondered the meaning of that set of cloudy phrases without much immediate success. But to Saul Shah-moon the robot’s explanation was lucidity itself. “Of course!” Saul cried. “A Dyson sphere!” Taking no notice of the interruption, Dihn Ruuu sailed serenely onward. “No communications have been received from the home world since the completion of the enclosure project,” the robot said. “However, there is every reason to believe that the Mirt Korp Ahm continue to inhabit their original solar system. Inasmuch as my own responsibilities have been terminated, I propose to journey at once to that system and request reassignment. It would please me if you were to accompany me there.”
Time out for explanations. I needed some myself, at this point.
A Dyson sphere, according to Saul, is a concept first put forth by an American physicist, Freeman Dyson, some time in the early years of the Energy Revolution. Dyson lived in the middle of the twentieth century, after the harnessing of atomic energy but before the colonization of Earth’s surrounding planets.
Dyson’s main point was that in its natural state a solar system is a terribly wasteful thing. The central sun, surrounded by a handful of planets, sends most of its energy shooting uselessly off into space. The planets are too widely separated to intercept more than a small fraction of the energy the sun generates; and therefore the sun’s output speeds away in all directions, radiating so intensely in the visible spectrum alone that its light can be seen thousands of light-years away. This has the esthetic advantage of producing lovely starry nights on distant worlds, but otherwise has little to commend it.
A really thrifty civilization, Dyson said, would catch all of its sun’s energy before it was squandered. One way to do it, he suggested, was to demolish Jupiter and use its mass to build a shell surrounding the sun at approximately the distance of Earth’s orbit from the center of the solar system. Smashing up the biggest planet and rearranging its pieces this way would take a fair amount of energy all by itself: roughly as much as the sun’s total output for eight hundred years. But once the job was finished, the shell would intercept every photon of energy coming from the sun; this could be put to use as an all-purpose power source.
Mankind would cease to live on the Earth, which even in his time was a pretty small and crowded place, and unsatisfactory in terms of application of solar energy, since at any given time half of it is receiving no solar radiation at all. Instead we would take up residence on the inner surface of the artificial sphere. Not only would every point on that surface have full access to sunlight at every moment, but the surface area of the sphere would be about one billion times greater than the surface area of the Earth. Splicing in all the plus factors, we’d find that the sphere could comfortably support a human population of 3 x 1023 individuals, which is to say a good many sextillion or septillion people — work out the exponents yourself. Anyway, it would be a gigantic number. Let’s see: Earth has thirteen billion people now, which is 13 x 109, and things are pretty crowded, and this would be a population increase of 1014, so … It gives you the dizzies, eh?