3001: The Final Odyssey

Frank Poole awoke, but he did not remember. He was not even sure of his name.

Obviously, he was in a hospital room. Even though his eyes were still closed, the most primitive and evocative of his senses told him that. Each breath brought the faint and not unpleasant tang of antiseptics in the air.

Now it was all beginning to come back. I'm Deputy Commander Frank Poole, executive officer, USSS Discovery, on a top secret mission to Jupiter.

It seemed as if an icy hand had gripped his heart. He remembered, in slow-motion playback, that runaway space pod jetting toward him, metal claws outstretched. Then the silent impact--and the not-so-silent hiss of air rushing out of his suit. After that--one last memory, of spinning helplessly in space, trying in vain to reconnect his broken air hose.

Whatever mysterious accident had happened to the space-pod controls, he was safe now. Presumably Dave Bowman had made a quick EVA and rescued him before the lack of oxygen could do permanent brain damage.

His confused train of thought was abruptly broken by the arrival of a matron and two nurses wearing the immemorial uniform of their profession. They seemed a little surprised: Poole wondered if he had awakened ahead of schedule, and the idea gave him a childish feeling of satisfaction.

"Hello!" he said after several attempts; his vocal cords appeared to be very rusty. "How am I doing?"

The matron smiled back at him and gave an obvious "Don't try to talk" command by putting a finger to her lips. Then the two nurses fussed swiftly over him with practiced skill, checking pulse, temperature, reflexes. When one of them lifted his right arm and let it drop again, Poole noticed something peculiar. It fell slowly and did not seem to weigh as much as normal. Nor, for that matter, did his body, when he attempted to move.

So I must be on a planet, he thought. Or a space station with artificial gravity. Certainly not Earth--I don't weigh enough.

He was about to ask the obvious question when the matron pressed something against the side of his neck. He felt a slight tingling sensation and sank back into a dreamless sleep. Just before he became unconscious, he had time for one more puzzled thought:

How odd--they never spoke a single word all the time they were with me.

When he woke again and found the matron and nurses standing around his bed, Poole felt strong enough to assert himself.

"Where am I? Surely you can tell me that!"

The three women then exchanged glances, obviously uncertain about what to do next. The matron answered, enunciating slowly and carefully: "Everything is fine, Mr. Poole. Professor Anderson will be here in a minute. He will explain."

Explain what? thought Poole with some exasperation. But at least she speaks English, even though I can't place her accent.

Anderson must have been already on his way, for the door opened moments later to give Poole a glimpse of a small crowd of inquisitive onlookers peering in at him. He began to feel like a new exhibit at a zoo.

Professor Anderson was a small, dapper man whose features seemed to have combined key aspects of several races--Chinese, Polynesian, Nordic--in a thoroughly confusing fashion. He greeted Poole by holding up his right palm, then did an obvious double take and shook hands with such curious hesitation that he might have been rehearsing some quite unfamiliar gesture.

"Glad to see you're looking so well, Mr. Poole. We'll have you up in no time."

Again that odd accent and slow delivery--but the confident bedside manner was that of all doctors, in all places and all ages.

"I'm glad to hear it. Now perhaps you can answer a few questions."

"Of course, of course. But just a minute."

Anderson spoke so rapidly and quietly to the matron that Poole managed to catch only a few words, several of which were wholly unfamiliar to him. Then the matron nodded at one of the nurses, who opened a wall cupboard and produced a slim metal band, which she proceeded to wrap around Poole's head.

"What's that for?" he asked--being one of those difficult patients, so annoying to doctors, who always want to know just what's happening to them. "EEG readout?"

Professor, the matron and nurses looked equally baffled. Then a slow smile spread across Anderson's face.

"Oh--electro...enceph...alo...gram," he said slowly, as if dredging the word up from the depths of his memory. "You're quite right. We just want to monitor your brain functions."

My brain would function perfectly well if you'd let me use it, Poole grumbled silently. But at least we seem to be getting somewhere--finally.

"Mr. Poole," said Anderson, still speaking in that curious stilted voice, as if venturing into a foreign language, "you know, of course, that you were...disabled...in a serious accident while you were working outside Discovery."

Poole nodded agreement.

"I'm beginning to suspect," he said dryly, "that 'disabled' may be a slight understatement."

Anderson relaxed visibly, and a slow smile spread across his face.

"You're quite correct. Tell me what you think happened."

"Well, the best-case scenario is that, after I became unconscious, Dave Bowman rescued me and brought me back to the ship. How is Dave? No one will tell me anything!"

"All in due course--and the worst case?"

It seemed to Frank Poole that a chill wind was blowing gently on the back of his neck. The suspicion that had been slowly forming in his mind began to solidify.

"That I died but was brought back here--wherever here is--and you've been able to revive me. Thank you...."

"Quite correct. And you're back on Earth. Well, very near it."

What did he mean by "very near it"? There was certainly a gravity field here--so he was probably inside the slowly turning wheel of an orbiting space station. No matter: There was something much more important to think about.

Poole did some quick mental calculations. If Dave had put him in the Hibernaculum, revived the rest of the crew and completed the mission to Jupiter--why, he could have been "dead" for as long as five years!

"Just what date is it?" he asked as calmly as possible.

Professor and the matron exchanged glances. Again Poole felt that cold wind on his neck.

"I must tell you, Mr. Poole, that Bowman did not rescue you. He believed--and we cannot blame him--that you were irrevocably dead. Also, he was facing a desperately serious crisis that threatened his own survival.

"So you drifted on into space, passed through the Jupiter system and headed out toward the stars. Fortunately, you were so far below freezing point that there was no metabolism--but it's a near-miracle that you were ever found at all. You are one of the luckiest men alive. No--ever to have lived!"

Am I? Poole asked himself bleakly. Five years, indeed! It could be a century--or even more.

"Let me have it," he demanded.

Professor and the matron seemed to be consulting an invisible monitor: When they looked at each other and nodded agreement, Poole guessed that they were all plugged into the hospital information circuit linked to the headband he was wearing.

"Frank," said Anderson, making a smooth switch to the role of longtime family physician, "this will be a great shock to you, but you're capable of accepting it--and the sooner you know, the better.

"We're near the beginning of the fourth millennium. Believe me--you left Earth almost a thousand years ago."

"I believe you," Poole answered calmly. Then, to his great annoyance, the room started to spin around him, and he knew nothing more.

•

Despite her name, Doctor Indra Wallace's chief racial component appeared to be Japanese. She was the first visitor with a fluent command of Poole's own English, so he was delighted to meet her.

"Mr. Poole," she began in a very businesslike voice, "I've been appointed your official guide and, let's say, your mentor. My qualifications--I've specialized in your period--my thesis was The Collapse of the Nation-State, 2000--2050. I believe we can help each other in many ways."

"I'm sure we can. First, I'd like you to get me out of here, so I can see a little of your world."

"Exactly what we intend to do. But first we must give you an Ident. Until then you'll be a--what was the term?--nonperson. It would be almost impossible for you to go anywhere or get anything done. No input device would recognize your existence."

Indra walked over to a small rectangular plate, set at eye level in the door. She laid the palm of her hand on the plate, then removed it after a few seconds. She glanced at Poole, and said smilingly, "Come and look at this."

The inscription that had suddenly appeared made a good deal of sense when he read it slowly:

Wallace, Indra

[F2970.03.11/31.885//Hist.Oxford//*//]

"I suppose it means female, date of birth 11 March 2970--and that you're associated with the Department of History at Oxford. And I guess that 31.885 is a personal identification number. Is that correct?"

"Excellent, Mr. Poole. As you see, it's a part of you."

"Implant?"

"Yes--nanochip at birth, one in each palm for redundancy. You won't even feel yours when they go in. But you've given us a small problem."

"What's that?"

"The readers you'll meet most of the time are too simpleminded to believe your date of birth. So, with your permission, we've moved it up a thousand years. And now, Frank, Professor Anderson thinks you're strong enough to go for a little walk."

"I'm very pleased to hear it. Do you know the expression 'stir crazy'?"

"No, but I can guess what it means."

Poole had so adapted to the low gravity that the long strides he was taking seemed perfectly normal. Half a g, he had estimated--just right to give a sense of well-being. Poole had followed Indra for perhaps 200 meters when he came to a halt, shocked because he had not realized something so blindingly obvious.

"This space station must be enormous!" he exclaimed.

Indra smiled back at him.

"Didn't you have a saying--'You ain't seen anything yet'?"

"Nothing," he said, correcting her absentmindedly. He was still trying to estimate the scale of this structure when he had another surprise. Who would have imagined a space station large enough to boast a subway--admittedly a miniature one, with a single small coach that is capable of seating only a dozen passengers?

"Observation Lounge Three," ordered Indra, and they drew silently and swiftly away from the terminal.

As far as Poole could judge by the speed and the elapsed time, they must have traveled at least three kilometers before the vehicle came to a silent stop, the doors opened and a bland autovoice intoned, "Have a good view. Thirty-five percent cloud cover today."

At last, thought Poole, we're getting near the outer wall. But here was another mystery: Despite the distance he had gone, neither the strength nor the direction of gravity had altered! He could not imagine a spinning space station so huge that the g vector would not be changed by such a displacement. Could he really be on some planet after all? But he would feel lighter--usually much lighter--on any other habitable world in the solar system.

When the outer door of the terminal opened and Poole found himself entering a small air lock, he realized he must indeed be in space. But where were the space suits? He looked around anxiously: It was against all his instincts to be so close to a vacuum, naked and unprotected. One experience of that was enough. "We're nearly there," Indra said reassuringly.

The last door opened, and he was looking out into the utter blackness of space through a huge window that was curved both vertically and horizontally. He felt like a goldfish in a bowl, and he hoped the designers of this audacious piece of engineering knew exactly what they were doing. They certainly possessed better structural materials than had existed in his time.

Though the stars must have been shining out there, his light-adapted eyes could see nothing but black emptiness beyond the curve of the great window. As he started to walk toward it to get a wider view, Indra restrained him and pointed straight ahead.

"Look carefully," she said. "Now do you see it?"

Poole blinked, and stared into the night. It must be an illusion--even, heaven forbid, a crack in the window!

He moved his head from side to side. No, it was real. But what could it be? He remembered Euclid's definition: "A line has length but no breadth."

For spanning the whole height of the window, and obviously continuing out of sight above and below, was a thread of light quite easy to see when he looked for it, yet so one-dimensional that the word thin could not even be applied. However, it was not completely featureless: There were barely visible spots of greater brilliance at irregular intervals along its length, like drops of water on a spider's web.

Poole continued walking toward the window, and the view expanded until at last he could see what lay below him. It was familiar enough; the whole continent of Europe and much of northern Africa, just as he had seen them many times from space. So he was in orbit after all--probably an equatorial one, at a height of at least a thousand kilometers.

Indra was looking at him with a quizzical smile.

"Go closer to the window," she said softly, "so that you can look straight down. I hope you have a good head for heights."

What a silly thing to say to an astronaut, Poole told himself as he moved forward. If I suffered from vertigo I wouldn't be in this business.

The thought had barely passed through his mind when he cried "My God!" and involuntarily stepped back from the window. Then, bracing himself, he dared to look again.

He was looking down on the distant Mediterranean from the face of a cylindrical tower, whose gently curving wall indicated a diameter of several kilometers. But that was nothing compared with its length, for it tapered away down, down, down--until it disappeared into the mists somewhere over Africa. He assumed that it continued all the way to the surface.

"How high are we?" he whispered.

"Two thousand k. But now take a look upward."

This time it was not such a shock; he had expected what he would see. The tower dwindled away until it became a glittering thread against the blackness of space, and he did not doubt that it continued all the way to the geostationary orbit, 36,000 kilometers above the equator. Such fantasies had been well known in Poole's day, yet he had never dreamed he would see the reality--and be living in it.

He pointed toward the distant thread reaching up from the eastern horizon.

"That must be another one."

"Yes--the Asia Tower. We must look exactly the same to them."

"How many are there?"

"Just four, equally spaced around the equator. Africa, Asia, America, Pacifica. The last one's almost empty--only a few hundred levels were completed. Nothing to see from that height except water."

Poole was still absorbing this stupendous concept when a disturbing thought occurred to him.

"There were already thousands of (continued on page 84)3001: The Final Odyssey(continued from page 70) satellites, at all sorts of altitudes, in my time. How do you avoid collisions?"

Indra paused for a moment. "I believe there was a big cleanup operation centuries ago. There just aren't any satellites below the stationary orbit."

That made sense, Poole told himself. They wouldn't be needed--the four gigantic towers could provide all the facilities once provided by thousands of satellites and space stations.

"And there have never been any accidents--any collisions with spaceships either leaving Earth or reentering the atmosphere?"

Indra shook her head

"But they don't, anymore." She pointed to the ceiling. "All the spaceports are up there, on the outer ring. I believe it's been 400 years since the last rocket lifted off from the surface of the Earth."

Poole was still digesting this when a trivial anomaly caught his attention. His training as an astronaut had made him alert to anything out of the ordinary. In space, that might be a matter of life or death.

The sun was out of view, high overhead, but its rays streaming down through the great window painted a brilliant band of light on the floor underfoot. Cutting across that band at an angle was another, much fainter, one, so that the frame of the window threw a double shadow.

Poole had to go almost down on his knees so that he could peer up at the sky. He had thought himself beyond amazement, but the spectacle of two suns left him momentarily speechless.

"What's that?" he gasped when he had recovered his breath.

"Oh--haven't you been told? That's Lucifer."

"Earth has another sun?"

"Well, it doesn't give us much heat, but it has put the moon out of business. Before the second mission went there to look for you, that was the planet Jupiter."

•

"There's no need to close your eyes," said the technician, who had been introduced by the pretentious title of brain engineer. "When setup begins, all your inputs will be taken over. Even if your eyes are open, you won't see anything."

I wonder if everyone feels as nervous as this, Poole asked himself. Is this the last moment I'll be in control of my own mind? Still, I've learned to trust the technology of this age; up to now, it hasn't let me down. Of course, as the old saying goes, there is always a first time.

As had been promised, he felt nothing except a gentle tickling as the myriad nanowires wormed their way through his scalp. All his senses were still perfectly normal; when he scanned his familiar room, everything was exactly where it should have been.

The brainman--wearing his own skullcap, wired like Poole's to a piece of equipment that could easily have been mistaken for a 20th century laptop computer--gave him a brief reassuring smile.

"Ready?" he asked.

There were times when those old clichés were the best ones.

"I'm as ready as I'll ever be," Poole answered.

Slowly the light faded--or seemed to. A great silence descended, and even the gentle gravity of the tower relinquished its hold on him. He was an embryo, floating in a featureless void, though not in complete darkness. He had known such a barely visible, nearultraviolet tenebrosity, on the very edge of night, only once in his life--when he had descended farther than was altogether wise down the face of a sheer cliff at the outer edge of the Great Barrier Reef. Looking down into hundreds of meters of crystalline emptiness, he had felt such a sense of disorientation that he experienced a brief moment of panic and had almost triggered his buoyancy unit before regaining control. Needless to say, he never mentioned the incident to the Space Agency physicians.

From a great distance, a voice spoke out of the immense void that now seemed to surround him. But it did not reach him through his ears; it sounded softly in the echoing labyrinths of his brain.

"Calibration starting. From time to time you will be asked questions--you can answer mentally, but it may help to vocalize. Do you understand?"

"Yes," Poole replied, wondering if his lips were indeed moving. There was no way he could tell.

Something was appearing in the void--a grid of thin lines, like a huge sheet of graph paper. It extended up and down, right and left, to the limits of his vision. He tried to move his head, but the image refused to change.

Numbers started to flicker across the grid, too fast for him to read--but presumably some circuit was recording them. Poole could not help smiling (did his cheeks move?) at the familiarity of it all. This was just like the computer-driven eye examination that any oculist of his age would have given a patient.

The grid vanished, to be replaced by smooth sheets of color filling his entire field of view. In a few seconds, they flashed from one end of the spectrum to the other. "Could have told you that," Poole muttered. "My color vision's perfect. Next for hearing, I suppose."

He was correct. A faint drumming sound accelerated until it became the lowest of audible Cs, then raced up the musical scale until it disappeared beyond the range of human beings, into bat and dolphin territory.

That was the last of the simple, straightforward tests. He was briefly assailed by scents and flavors, most of them pleasant but some quite the reverse. Then he became, or so it seemed, a puppet on an invisible string.

He presumed that his neuromuscular control was being tested, and hoped there were no external manifestations; if there were, he would probably look like someone in the terminal stages of St. Vitus' dance. And for one moment he even had a violent erection but was unable to give it a reality check before he fell into a dreamless sleep.

Or did he dream that he slept? He had no idea how much time had elapsed before he awoke. The helmet was gone, along with the brainman and his equipment.

"Everything went fine," the matron said, beaming. "It will take a few hours to check that there are no anomalies. If your reading's KO--I mean OK--you'll have your braincap tomorrow."

Poole appreciated the efforts of his entourage to learn archaic English, but he could not help wishing that the matron had not made that unfortunate slip of the tongue.

•

When the time came for the final fitting, Poole felt almost like a boy again, about to unwrap some wonderful new toy under the Christmas tree.

"You won't have to go through all that setting up again," the brainman assured him. "Download will start immediately. I'll give you a five-minute demo. Just relax and enjoy."

Gentle, soothing music washed over him; though it was something familiar, from his own time, he could not identify it. There was a mist before his eyes, which parted as he walked toward it.

Yes, he was walking! The illusion was utterly convincing. He could feel the impact of his feet on the ground, and now that the music had stopped he could hear a gentle wind blowing through the great trees that appeared to surround him. He recognized them as California redwoods and hoped that they still existed in reality, somewhere on Earth.

He was moving at a brisk pace--too fast for comfort, as if time had been slightly accelerated so he could cover as much ground as possible. Yet he was not conscious of any effort; he felt he was a guest in someone else's body. The sensation was enhanced by the fact that he had no control over his movements. When he attempted to stop, or to change direction, nothing happened. He was going along for the ride.

It did not matter. He was enjoying the novel experience and could appreciate how addictive it could become. The "dream machines" that many scientists of his own century had anticipated--often with alarm--were now part of everyday life. Poole wondered how mankind had managed to survive--indeed, he had been told that much of it had not. Millions had been brain-burned and had dropped out of life.

Of course, he would be immune to such temptations! He would use this marvelous tool to learn more about the world of the third millennium and to acquire in minutes new skills that would otherwise have taken years to master. Well, he might, just occasionally, use the braincap purely for fun.

He had come to the edge of the forest and was looking out across a wide river. Without hesitation, he walked into it and felt no alarm as the water rose over his head. It did seem a little strange that he could continue breathing naturally, but he thought it much more remarkable that he could see perfectly in a medium where the unaided human eye cannot focus. He could count every scale on the magnificent trout that went swimming past, apparently oblivious to this strange intruder.

A mermaid! Well, he had always wanted to meet one, but he had assumed they were marine creatures. Perhaps they occasionally went upstream like salmon to have their babies. She was gone before he could question her, to confirm or deny this revolutionary theory.

The river ended in a translucent wall; he stepped through it onto the face of a desert beneath a blazing sun. Its heat burned him uncomfortably, yet he was able to look directly into its noonday fury. He could even see, with unnatural clarity, an archipelago of sunspots near one limb. And--this was surely impossible!--there was the tenuous glory of the corona, quite invisible except during a total eclipse, reaching out like swans' wings on either side of the sun.

Everything faded to black: The haunting music returned, and with it the blissful coolness of his familiar room. He opened his eyes (had they ever been closed?) and found an expectant audience waiting for his reaction.

"Wonderful!" he breathed almost reverently. "Some of it seemed, well, realer than real!"

Then his engineer's curiosity, never far from the surface, started nagging at him.

"Even that short demo must have contained an enormous amount of information. How's it stored?"

"In these tablets. Your audiovisual system uses the same, but with much greater capacity."

The brainman handed Poole a small square, apparently made of glass, silvered on one surface. It was almost the size of the computer diskettes of his youth but twice the thickness. As Poole tilted it back and forth, trying to see into its transparent interior, there were occasional rainbow-hued flashes, but that was all.

He was holding, he realized, the end product of more than a thousand years of electro-optical technology--as well as other technologies unborn in his era. And it was not surprising that, superficially, it closely resembled the devices he had known. There was a convenient shape and size for most of the common objects of everyday life--knives and forks, books, hand tools, furniture--and removable memories for computers.

"What's its capacity?" he asked. "In my time, we were up to a terabyte in something this size. I'm sure you've done a lot better."

"Not as much as you might imagine--there's a limit, of course, set by the structure of matter. By the way, what was a terabyte? I'm afraid I have forgotten."

"Shame on you! Kilo, mega, giga, tera--that's ten to the twelfth bytes. Then the petabyte--ten to the fifteenth. That's as far as I ever got."

"That's about where we start. It's enough to record everything that any person can experience during one lifetime."

It was an astonishing thought, yet it should not have been so surprising. The kilogram of jelly inside the human skull was not much larger than the tablet Poole was holding in his hand, and it could not possibly be as efficient a storage device--it had so many other duties to deal with.

"And that's not all," the brainman continued. "With some data compression, it could store not only the memories but also the actual person."

"And reproduce him again?"

"Of course. Straightforward job of nanoassembly."

So I'd heard, Poole told himself, but I never really believed it.

Back in his century, it seemed wonderful enough that the entire lifework of a great artist could be stored on a single small disk.

And now something no larger could hold the artist as well.

•

"Now I've some good news. Anderson has finally given his--what was the phrase?--OK. You're fit enough to go for a little trip upstairs...to the lunar level."

"Wonderful. How far is that?"

"Oh, about 12,000 kilometers."

"Twelve thousand? That will take hours!"

Indra looked askance at his remark, then she smiled.

"Not as long as you think. No--we don't have a Star Trek transporter yet, though I believe they're working on it! But first you'll need new clothes, and someone to show you how to wear them. And to help you with the hundreds of little everyday jobs that can waste so much time. So we've taken the liberty of arranging a human personal assistant for you. Come in, Danil."

Danil was a small, light-brown man in his mid-30s, who surprised Poole by not giving him the usual palm-to-palm salute, with its automatic exchange of information. Indeed, it soon appeared that Danil did not possess an Ident. Whenever it was needed, he produced a small rectangle of plastic that apparently served the same purpose as the 21st century's smart card.

"Danil will also be your guide and--what was that word? I can never remember. Rhymes with ballet. He's been specially trained for the job. I'm sure that you will find him completely satisfactory."

Though Poole appreciated this gesture, it made him feel a little uncomfortable. A valet, indeed. He could not recall ever meeting one; in his time, they were already a rare and endangered species. He began to feel like a character from an early 20th century English novel.

"You have a choice," said Indra, "though I know which one you'll take. We can go up on an external elevator and admire the view--or on an interior one and enjoy a meal and some light entertainment."

(continued on page 92)3001: The Final Odyssey(continued from page 86)

"I can't imagine anyone wanting to stay inside."

"You'd be surprised. It's too vertiginous for some people--especially visitors from down below. Even mountain climbers who say they have a head for heights may start to turn green when the heights are measured in thousands of kilometers, instead of meters."

"I'll risk it," Poole answered with a smile. "I've been higher."

When they had passed through a double set of air locks in the exterior wall of the tower (was it his imagination or did he feel a curious sense of disorientation then?), they entered what might have been the auditorium of a small theater. Rows of ten seats were banked up in five tiers; they all faced one of the huge picture windows that Poole still found disconcerting, as he could never quite forget the hundreds of tons of air pressure striving to blast it out into space.

The dozen or so other passengers, who had probably never given the matter any thought, seemed perfectly at ease. They all smiled as they recognized him, nodded politely and then turned away to admire the view.

"Welcome to Skylounge," said the inevitable autovoice. "Ascent begins in five minutes. You will find refreshments and toilets on the lower floor."

Just how long will this trip last? Poole wondered. We're going to travel more than 20,000 klicks, there and back: This will be like no elevator ride I ever knew on Earth.

While he was waiting for the ascent to begin, he enjoyed the panorama laid out 2000 kilometers below. It was winter in the northern hemisphere, but the climate had indeed changed drastically, for there was little snow south of the Arctic Circle.

Europe was almost cloud-free, and there was so much detail that the eye was overwhelmed. One by one he identified the great cities whose names had echoed down the centuries. They had been shrinking even in his time, as the communications revolution changed the face of the world, and had now dwindled still further. There were also some bodies of water in improbable places--the northern Sahara's Lake Saladin was almost a small sea.

Poole was so engrossed by the view that he had forgotten the passage of time. Suddenly he realized that much more than five minutes had passed--yet the elevator was still stationary. Had something gone wrong, or were they waiting for late arrivals?

And then he noticed something so extraordinary that at first he refused to believe the evidence of his eyes. The panorama had expanded, as if he had already risen hundreds of kilometers! Even as he watched, he noticed new features of the planet below creeping into the frame of the window.

Then Poole laughed, as the obvious explanation occurred to him.

"You could have fooled me, Indra! I thought this was real--not a video projection!"

Indra looked at him with a quizzical smile.

"Think again, Frank. We started to move about ten minutes ago. By now we must be climbing at, oh, at least 1000 kilometers an hour. Though I'm told these elevators can reach a hundred gs at maximum acceleration, we won't touch more than ten on this short run."

"That's impossible! Six is the maximum they ever gave me in the centrifuge, and I didn't enjoy weighing half a ton. I know we haven't moved since we stepped inside."

Poole had raised his voice slightly and suddenly became aware that the other passengers were pretending not to notice.

"I don't understand how it's done, Frank, but it's called an inertial field. Or sometimes a Sharp one--the S stands for a famous Russian scientist, Sakharov. I don't know who the others were."

Slowly, understanding dawned in Poole's mind--and also a sense of awestruck wonder. Here, indeed, was a technology indistinguishable from magic.

"Some of my friends used to dream of 'space drives'--energy fields that could replace rockets and allow movement without any feeling of acceleration. Most of us thought they were crazy--but it seems they were right! I can still hardly believe it...and unless I'm mistaken, we're starting to lose weight."

"Yes--it's adjusting to the lunar value. When we step out, you'll feel we're on the moon. But for goodness' sake, Frank, forget you're an engineer and simply enjoy the view."

It was good advice, but even as he watched Africa, Europe and much of Asia flow into his field of vision, Poole could not tear his mind away from this astonishing revelation. Yet he should not have been wholly surprised: He knew that there had been major breakthroughs in space propulsion systems since his time but had not realized they would have such dramatic applications to everyday life--if that term could be applied to existence in a 36,000-kilometer-high skyscraper.

And the age of the rocket must have been over centuries ago. All his knowledge of propellant systems and combustion chambers, ion thrusters and fusion reactors, was totally obsolete. Of course, that no longer mattered--but he understood the sadness that the skipper of a windjammer must have felt when sail gave way to steam.

His mood changed abruptly, and he could not help smiling when the autovoice announced, "Arriving in two minutes. Please make sure you do not leave any of your personal belongings behind."

How often had he heard that announcement on some commercial flight. He looked at his watch and was startled to see that they had been ascending for less than half an hour--that meant an average speed of at least 20,000 kilometers an hour, yet they might never have moved. What was even stranger, for the past ten minutes or more they must actually have been decelerating so rapidly that by rights they should all have been standing on the roof, heads pointing toward Earth!

The doors opened silently, and as Poole stepped out he again felt the slight disorientation he had noticed on entering the elevator lounge. This time, however, he knew what it meant: He was moving through the transition zone where the inertial field overlapped with gravity--at this level, equal to the moon's.

Indra and Danil followed him, walking carefully now at a third of their customary weight, as they went forward to meet the next of the day's wonders.

Though the view of the receding earth had been awesome, even for an astronaut, there was nothing unexpected about it. But who would have imagined a gigantic chamber, apparently occupying the entire width of the tower, so that the far wall was more than five kilometers away? Perhaps by this time there were larger enclosed volumes on the moon and Mars, but this must surely be one of the largest in space itself.

They were standing on a viewing platform, 50 meters up on the outer wall, looking across an astonishingly varied panorama. Obviously, an attempt had been made to reproduce a whole range of terrestrial biomes. (concluded on page 158)3001: The Final Odyssey(continued from page 92) Immediately beneath them was a group of slender trees that Poole could not at first identify. Then he realized they were oaks, adapted to one sixth of their normal gravity. What, he wondered, would palm trees look like here? Giant reeds, probably.

In the middle distance there was a small lake, fed by a river that meandered across a grassy plain, then disappeared into something that looked like a single gigantic banyan tree. What was the source of the water? Poole had become aware of a faint drumming sound, and as he swept his gaze along the gently curving wall, he discovered a miniature Niagara with a perfect rainbow hovering in the spray above it.

He could have stood there for hours, admiring the view and still not exhausting all the wonders of this complex and brilliantly contrived simulation of the planet below. As it spread out into new and hostile environments, perhaps the human race felt an ever-increasing need to remember its origins. Of course, even in his own time every city had its parks as reminders--usually feeble--of nature. The same impulse must be acting here on a much grander scale. Central Park, Africa Tower!

"Let's go down," said Indra. "There's so much to see, and I don't come here as often as I'd like."

Followed by the silent but ever-present Danil, who always seemed to know when he was needed but otherwise kept out of the way, they began a leisurely exploration of this oasis in space. Though walking was almost effortless in this low gravity, from time to time they took advantage of a small monorail, and stopped once for refreshments at a café cunningly concealed in the trunk of a redwood that must have been at least a quarter of a kilometer tall.

There were very few other people about--their fellow passengers had long since disappeared into the landscape--so it was as if they had all this wonderland to themselves. Everything was so beautifully maintained, presumably by armies of robots, that from time to time Poole was reminded of a visit he had made to Disney World as a small boy. But this was even better: There were no crowds and indeed very little reminder of the human race and its artifacts.

They were admiring a superb collection of orchids, some of enormous size, when Poole had one of the biggest shocks of his life. As they walked past a typical gardener's shed, the door opened--and the gardener emerged.

Frank Poole had always prided himself on his self-control and never imagined that as a full-grown adult he would give a cry of pure fright. But like every boy of his generation, he had seen the Jurassic movies--and he knew a raptor when he met one eye-to-eye.

"I'm terribly sorry," Indra said, with obvious concern. "I never thought of warning you."

Poole's jangling nerves returned to normal. Of course there could be no danger in this perhaps too-well-ordered world, but still!

The dinosaur returned his stare with apparent disinterest, then doubled back into the shed and emerged again with a rake and a pair of garden shears, which it dropped into a bag hanging over one shoulder. It walked away from them with a birdlike gait, never looking back as it disappeared behind some ten-meter-high sunflowers.

"I should explain," Indra said contritely. "We like to use bio-organisms when we can, rather than robots--I suppose it's carbon chauvinism! There are only a few animals that have any manual dexterity, and we've used them all at one time or another.

"And here's a mystery that no one's been able to solve. You'd think that enhanced herbivores such as chimps and gorillas would be good at this sort of work. Well, they're not; they don't have the patience for it.

"Yet carnivores like our friend here are excellent, and easily trained. What's more--here's another paradox!--after they've been modified they're docile and good-natured. Of course, there are almost a thousand years of genetic engineering behind them, and look what primitive man did to the wolf, merely by trial and error!"

Indra laughed and continued: "You may not believe this, Frank, but they also make good babysitters--children love them! There's a 500-year-old joke: 'Would you trust your kids to a dinosaur?' 'What--and risk injuring it?'"

Poole joined in the laughter, partly in shamefaced reaction to his own fright. To change the subject, he asked Indra the question that was still worrying him.

"All this," he said, "is wonderful, but why go to so much trouble when anyone in the tower can reach the real thing just as quickly?"

Indra looked at him thoughtfully, weighing her words.

"That's not quite true. It's uncomfortable--even dangerous--for anyone who lives above the half-g level to go down to Earth, even in a hoverchair. So it has to be this or--as you used to say--virtual reality."

Now I'm beginning to understand, Poole told himself. That explains Anderson's evasiveness, and all the tests he's been doing to see if I've regained my strength.

I've come all the way back from Jupiter, to within 2000 kilometers of Earth--but I may never again walk on the surface of my home planet.

Looking down into the crystalline emptiness, he experienced a brief moment of panic.

The age of the rocket must have been over centuries ago. All his knowledge was obsolete.

The dinosaur returned his stare, doubled back into the shed and emerged with a rake and garden shears.