"Then I don't do it that way. I wear a spacesuit, and I crawl up the drive tunnel and reach out a finger..."
"How clever of you to hit exactly the right spot! But if you did, when your finger got within — oh —something like a millimeter, I'd guess — the gravitational tidal forces would start to tear away at it. As soon as the first few atoms fell into the field, they'd give up all their mass-energy — and you'd think that a small hydrogen bomb had gone off in your face. The explosion would probably blow you out of the tube at a fair fraction of the speed of light."
Duncan gave an uncomfortable little laugh.
"It would certainly take a clever man to steal one of your babies. Doesn't it ever give you nightmares?"
"No. It's the tool I'm trained to use, and I understand its little ways. I can't imagine handling power lasers — they scare the hell out of me. You know, old Kipling had it all summed up, as usual. You remember me talking about him?"
"Yes."
"He wrote a poem called ‘The Secret of the Machines,’ and it has some lines I often say to myself when I'm down here:
"But remember, please, the Law by which we live,
We are not built to comprehend a lie,
We can neither love nor pity nor forgive.
If you make a slip in handling us you die!
"And that's true of all machines — all the natural forces we've ever learned to handle. There's no real difference between the first caveman's fire and the node in the heart of the Asymptotic Drive."
An hour later, Duncan lay sleepless in his bunk, waiting for the Drive to go on and for Sirius to begin the ten days of deceleration that would lead to her rendezvous with Earth. He could still see that tiny flaw in the structure of space, hanging there in the field of the microscope, and knew that its image would haunt him for the rest of his life. And he realized now that Warren Mackenzie had betrayed nothing of his trust; all that he had learned had been published a thousand times. But no words or photos could ever convey the emotional impact he had experienced.
Tiny fingers began to tug at him; weight was returning to Sirius. From an infinite distance came the thin wail of the Drive; Duncan told himself that he was listening to the death cry of matter as it left the known universe, bequeathing to the ship all the energy of its mass in the final moment of dissolution. Every minute, several kilograms of hydrogen were falling into that tiny but insatiable vortex — the hole that could never be filled.
Duncan slept poorly for the rest of the night. He had dreams that he too was falling, falling into a spinning whirlpool, indefinitely deep. As he fell, he was being crushed to molecular, to atomic, and finally to subnuclear dimensions. In a moment, it would all be over, and he would disappear in a single flash of radiation...
But that moment never came, because as Space contracted, Time stretched endlessly, the passing seconds becoming longer... and longer — until he was trapped forever in a changeless Eternity.
16
Port Van Allen
When Duncan had gone to bed for the last time aboard Sirius, Earth was still five million kilometers away. Now it seemed to fill the sky — and it was exactly like the photographs. He had laughed when more seasoned travelers told him he would be surprised at this; now he was ruefully surprised at his surprise.
Because the ship had cut right across the Earth's orbit, they were approaching from sunward, and the hemisphere below was almost fully illuminated. White continents of cloud covered most of the day side, and there were only rare glimpses of land, impossible to identify without a map. The dazzling glare of the Antarctic icecap was the most prominent surface feature; it looked very cold down there, yet Duncan reminded himself that it was tropical in comparison with much of his world.
Earth was a beautiful planet; that was beyond dispute. But it was also alien, and its cool whites and blues did nothing to warm his heart. It was indeed a paradox that Titan, with its cheerful orange clouds, looked so much more hospitable from space.
Duncan stayed in Lounge B, watching the approaching Earth and making his farewells to many temporary friends, until Port Van Allen was a dazzling star against the blackness of space, then a glittering ring, then a huge, slowly turning wheel. Weight gradually ebbed away as the drive that had taken them halfway across the Solar System decreased its thrust to zero; then there were only occasional nudges as low-powered thrustors trimmed the attitude of the ship.
The space station continued to expand. Its size was incredible, even when one realized that it had been steadily growing for almost three centuries. Now it completely eclipsed the planet whose commerce it directed and controlled; a moment later a barely perceptible vibration, instantly damped out, informed everybody that the ship had docked. A few seconds later, the Captain confirmed it.
"Welcome to Port Van Allen — Gateway to Earth. It's been nice having you with us, and I hope you enjoy your stay. Please follow the stewards, and check that you've left nothing in your cabins. And I'm sorry to mention this, but three passengers still haven't settled their accounts. The Purser will be waiting for them at the exit..."
A few derisive groans and cheers greeted this announcement, but were quickly lost in the noisy bustle of disembarkation. Although everything was supposed to have been carefully planned, chaos was rampant. The wrong passengers went to the wrong checkpoints, while the public-address system called plaintively for individuals with improbable names. It took Duncan more than an hour to get into the spaceport, and he did not see all of his baggage again until his second day on Earth.
But at last the confusion abated as people squeezed through the bottleneck of the docking hub and sorted themselves out in the appropriate levels of the station. Duncan followed instructions conscientiously, and eventually found himself, with the rest of his alphabetical group, lined up outside the Quarantine Office. All other formalities had been completed hours ago, by radio circuit; but this was something that could not be done by electronics. Occasionally, travelers had been turned back at this point, on the very doorstep of Earth, and it was not without qualms that Duncan confronted this last hurdle.
"We don't get many visitors from Titan," said the medical officer who checked his record. "You come in the Lunar classification — less than a quarter gee. It may be tough down there for the first week, but you're young enough to adapt. It helps if both your parents were born..."
The doctor's voice trailed off into silence; he had come to the entry marked MOTHER. Duncan was used to the reaction, and it had long ago ceased to bother him. Indeed, he derived a certain amusement from the surprise that discovery of his status usually produced. At least the M.O. would not ask the silly question that laymen so often asked, and to which he had long ago formulated an automatic reply: "Of course I've got a navel — the best that money can buy." The other common myth — that male close must be abnormally virile "because they had one father twice" — he had wisely left unchallenged. It had been useful to him on several occasions.
Perhaps because there were six other people waiting in line, the doctor suppressed any scientific curiosity he may have felt, and sent Duncan "upstairs" to the Earth-gravity section of the spaceport. It seemed a long time before the elevator, moving out along one of the spokes of the slowly spinning wheel, finally reached the rim; and all the while, Duncan felt his weight increasing remorselessly.
When the doors opened at last, he walked stiff-legged out of the cage. Though he was still a thousand kilometers above the Earth, and his new-found weight was entirely artificial, he felt that he was already in the cruel grip of the planet below. If he could not pass the test, he would be shipped back to Titan in disgrace.
It was true that those who just failed to make the grade could take a high-speed toughening-up course, primarily intended for returning Lunar residents. This, however, was safe only for those who had spent most of their infancy on Earth, and Duncan could not possibly qualify.
He forgot all these fears when he entered the lounge and saw the crescent Earth, filling hal
f the sky and slowly sliding along the huge observation windows — themselves a famous tour de force of space engineering. Duncan had no intention of calculating how many tons of air pressure they were resisting; as he walked up to the nearest, it was easy to imagine that there was nothing protecting him from the vacuum of space. The sensation was both exhilarating and disturbing.
He had intended to go through the check list that the doctor had given him, but that awesome view made it impossible. He stood rooted to the spot, only shifting his unaccustomed weight from one foot to the other as hitherto unknown muscles registered their complaints.
Port Van Allen circled the globe every two hours, and also rotated on its own axis three times a minute. After a while, Duncan found that he could ignore the station's own spin; his mind was able to cancel it out, like an irrelevant background noise or a persistent but neutral odor. Once he had achieved this mental attitude, he could imagine that the was alone in space, a human satellite racing along the Equator from night into day. For the Earth was waxing visibly even as he watched, the curved line of dawn moving steadily away from him as he hurtled into the east.
As usual, there was little land visible, and what could be seen through or between the clouds seemed to have no relationship to any maps. And from this altitude there was not the slightest sign of life — still less of intelligence. It was very hard to believe that most of human history had take place beneath that blanket of brilliant white, and that, until a mere three hundred years ago, no man had ever risen above it.
He was still searching for signs of life when the disc started to contract to a crescent once more, and the public-address system called on all passengers for Earth to report to the shuttle embarkation area, Elevators Two and Three.
He just had time to stop of the "Last Chance" toilet — almost as famous as the lounge windows — and then he was down by elevator again, back into the weightless world of the station's hub, where the Earth-to-orbit shuttle was being readied for its return journey.
There were no windows here, but each passenger had his own vision screen, on the back of the seat in front of him, and could switch to forward, rear, or downward as preferred. The choice was not completely free, though this fact was not widely advertised. Images that were likely to be too disturbing — like the final moments of docking or touchdown — were thoughtfully censored by the ship's computer.
It was pleasant to be weightless again — if only during the fifty minutes needed for the fall down to the edge of the atmosphere — and to watch the Earth slowly changing from a planet to a world. The curve of the horizon became flatter and flatter; there were fleeting glimpses of island and the spiral nebula of a great storm, raging in silence far below. Then at last a feature that Duncan could recognize — the characteristic narrow isthmus of the California coastline, as the shuttle dropped out of the Pacific skies for its final landfall, still the width of a continent away.
He felt himself sinking deeper and deeper into the superbly padded seat, which spread the load so evenly over his body that there was the minimum of discomfort. But it was hard to breathe, until he remembered the "Advice to Passengers" he had finally managed to read. Don't try to inhale deeply, it had said; take short, sharp pants, to reduce the strain on the chest muscles. He tried it, and it worked.
Now there was a gently buffeting and a distant roar, and the vision screen flared into momentary flame, then switched automatically from the fires of reentry to the view astern. The canyons and deserts dwindled behind, to be replace by a group of lakes — obviously artificial, with the tiny white flecks of sailboats clearly visible. He caught a glimpse of the huge V-shaped wake, kilometers long, of some vessel going at great speed over the water, although from this altitude it seemed completely motionless.
Then the scene changed with an abruptness that took him by surprise. He might have been flying over the ocean once more, so uniform was the view below. Still so high that he could not see the individual trees, he was passing over the endless forests of the American Midwest.
Here indeed was proof of Life, on a scale such as he had never imagined. On all of Titan, there were fewer than a hundred trees, cherished and protected with loving care. Spread out beneath him now were incomputable millions.
Somewhere, Duncan had encountered the phrase "primeval forest," and now it flashed again into his mind. So must the Earth have looked in the ancient days, before Man had set to work upon it with fire and axe. Now, with the ending of the brief Agricultural Age, much of the planet was reverting to something like its original state.
Though the fact was very hard to believe, Duncan knew perfectly well that the "primeval forest" lying endlessly beneath him was not much older than Grandfather. Only two centuries ago, this had all been farmland, divided into enormous checkerboards and covered in the autumn with golden grain. "That concept of seasons was another local reality he found extremely difficult to grasp...) There were still plenty of farms in the world, run by eccentric hobbyists or biological research organizations, but the disasters of the twentieth century had taught men never again to rely on a technology that, at its very best, had an efficiency of barely one percent.
The sun was sinking, driven down into the west with unnatural speed by the shuttle's velocity. It clung to the horizon for a few seconds, then winked out. For perhaps a minute longer the forest was still visible; then it faded into obscurity.
But not into darkness. As if by magic, faint lines of light had appeared on the land below — spiders' webs of luminosity, stretching as far as the eye could see. Sometimes three or four lines would meet at a single glowing knot. There were also isolated islands of phosphorescence, apparently unconnected with the main network. Here was further proof of Man's existence; that great forest was a much busier place than it appeared to be by daylight. Yet Duncan could to help comparing this modest display with pictures he had seen from the early Atomic Age, when millions of square kilometers blazed at night with such brilliance that men could no longer see the stars.
He suddenly became aware of a compact constellation of flashing lights, moving independently of the glimmering landscape far below. For a moment, he was baffled; then he realized that he was watching some great airship, cruising not much faster than a cloud with its cargo of freight or passengers. This was one experience Titan could not provide. He determined to enjoy it as soon as the opportunity arose.
And there was a city — quite a big one, at least a hundred thousand people. The shuttle was now so low that he could make out blocks of buildings, roads, parks, and a stadium blazing with light, presumably the scene of some sporting event. The city fell astern, and a few minutes later everything was lost in a gray mist, lit by occasional flashes of lightning, not very impressive by the standards of Titan. Inside the cabin, Duncan could hear nothing of the storm through which they were now flying, but the vibration of the engines had taken on a new note and he could sense that the ship was dropping rapidly. Nevertheless, he was taken completely by surprise when there was a sudden surge of weight, the slightest of jolts — and there on the screen was a sea of wet concrete, a confusion of lights, and half a dozen buses and service vehicles scurrying around in the driving rain.
After thirty years, Duncan Makenzie had returned to the world where he was born, but which he had never seen...
Part Three
Terra
17
Washington, D.C.
"Sorry about the weather," said George Washington. "We used to have local climate control, but gave it up after an Independence Day parade was blocked by snow."
Duncan laughed dutifully, though he was not quite sure if he was supposed to believe this.
"I don't mind," he said. "It's all new to me. I've never seen rain before."
That was not the literal truth, but it was near enough. He had often driven through ammonia gales and could still remember the poisonous cascades streaming down the windows only a few centimeters before his eyes. But this was harmless — no, beneficent — wa
ter, the source of life both on Earth and on Titan. If he opened the door now he would merely get wet; he would not die horribly. But the instincts of a lifetime were hard to overcome, and he knew that it would require a real effort of will to leave the protection of the limousine.
And it was a genuine limousine — another first for Duncan. Never before had he traveled in such sybaritic comfort, with a communications console on one side and a well-stocked bar on the other. Washington saw his admiring gaze and commented: "Impressive, isn't it? They don't make them any more. This was President Bernstein's favorite car."
Duncan was not too good on American presidents — after all, there had been by now ninety-five of them — but he had an approximate idea of Bernstein's date. He performed a quick calculation, didn't believe the result, and repeated it.
"That means — it's more than a hundred and fifty years old!"
"And it's probably good for another hundred and fifty. Of course, the upholstery — real leather, notice — is replaced every twenty years or so. If these seats could talk, they could tell some secrets. As a matter of fact, they often did — by you have my personal assurance that it's now been thoroughly debugged."
"Debugged? Oh, I know what you mean. Anyway, I don’t have any secrets."
"Then we'll soon provide you with some; that's our chief local industry."
As the beautiful old car cruised in almost perfect silence under the guidance of its automatic controls, Duncan tried to see something of the terrain through which he was passing. The spaceport was fifty kilometers from the city — no one had yet invented a noiseless rocket — and the four-lane highway bore a surprising amount of traffic. Duncan could count at least twenty vehicles of various types, and even though they were all moving in the same direction, the spectacle was somewhat alarming.
"I hope all those other cars are on automatic," he said anxiously.