Nemesis

71



Crile Fisher watched the bright star thoughtfully.



At first, it had been too bright to watch in the ordinary sense. He had glanced at it every once in a while and would see a bright after-image. Tessa Wendel, who was in a state of despair over developments, had scolded and spoken of retinal damage, so he had opacified the viewport and had brought the brightness of the star down to just bearable levels. That dimmed the other stars to a downcast, tarnished glitter.



The bright star was the Sun, of course.



It was farther away than any human being had ever seen it (except for the people of Rotor on their journey away from the Solar System). It was twice as far away as one would see it from Pluto at its farthest, so that it showed no orb and shone with the appearance of a star. Nevertheless, it was still a hundred times the brightness of the full Moon as seen from Earth, and that hundredfold brightness was condensed and compacted into one brilliant point. No wonder one still couldn't bear to turn a direct and unflinching gaze upon it through an un-opacified glass.



It made things different. The sun, ordinarily, was nothing to wonder at. It was too bright to look at, too unrivaled in its position. The minor portion of its light that was scattered into blueness by the atmosphere was sufficient to blank out the other stars altogether, and even where the stars were not blanked out (as on the Moon, for instance) they were so overridden by the Sun that there was no thought of comparison.



Here, so far out in space, the Sun had dimmed at least to the point where comparison was possible. Wendel had said that from this vantage point, the Sun was one hundred and sixty thousand times as bright as Sirius, which was the next brightest object in the sky. It was perhaps twenty million times as bright as the dimmest stars he could see by eye. It made the Sun seem more marvelous by comparison than when it shone, uncompared, in Earth's sky.



Nor did he have much more to do than watch the sky, for the Superluminal was merely drifting. It had been doing that for two days - two days of drifting through space at mere rocket velocities.



At this speed it would take thirty-five thousand years to reach the Neighbor Star - if they had been heading in the right direction. And they weren't.



It was this that had turned Wendel, two days earlier, into a picture of white-faced despair.



Until then, there had been no trouble. When they were due to enter hyperspace, Fisher had tensed himself, fearing the possible pain, the piercing flash of agony, the sudden surge of eternal darkness.



None of that had happened. It had all been too fast to experience. They had entered into and emerged from hyperspace in the same instant. The stars had simply blinked into a different pattern with no perceptible moment in which they had lost their first pattern, yet not gained their second.



It was relief in a double sense. Not only was he still alive, but he realized that if something had gone wrong and he had died, then death would have come in such a no-time way that he could not possibly have experienced death. He would simply have been dead.



The relief was so keen that he was scarcely aware that Tessa had let out a gasp of disturbance and pain, and dashed out to the engine room with an outcry.



She came back looking disheveled - not a hair out of place, but looking internally disheveled. Her eyes were wild and she stared at Fisher as though she did not really recognize him.



She said, 'The pattern should not have changed.'



'Shouldn't it?'



'We haven't moved far enough. Or shouldn't have. Only one and a third milli-light-years. That would not have been enough to alter the star pattern to the unaided eye. However' - she drew a deep, shuddering breath -'it's not as bad as it might have been. I thought we had slipped and moved out thousands of light-years.'



'Would that have been possible, Tessa?'



'Of course it would have been possible. If our passage through hyperspace weren't tightly controlled, a thousand light-years is as easy as one.'



'In that case, we can as easily just go-'



Wendel anticipated the conclusion. 'No, we couldn't just go back. If our controls were that slipshod, every pass we would make would be uncontrolled travel, ending at some random point, and we'd never find our way back.'



Fisher frowned. The euphoria of having passed through hyperspace and back - and stayed alive - began to leak away. 'But when you sent out test objects, you brought them back safely.'



'They were far less massive and were sent out through far shorter distances. But, as I said, it's not too bad. It turns out we went the correct distance. The stars are in the correct pattern.'



'But they changed. I saw them change.'



'Because we're oriented differently. The long axis of the ship has veered through an angle of better than twenty-eight degrees. In short, we followed a curved path rather than a straight one for some reason.'



The stars, as seen through the viewport, were moving now, slowly, steadily.



Wendel said, 'We're turning to face the Neighbor Star again, just for the psychological value of facing in the right direction, but then we must find out why we curved in passage.'



The bright star, the beacon star, the star of brilliance entered the viewport and moved across it. Fisher blinked.



'That's the Sun,' said Wendel, answering Fisher's look of astonishment.



Fisher said, 'Are there any reasonable explanations why the ship curved in passage? If Rotor also curved, who knows where they ended?'



'Or where we will end either. Because I don't have any reasonable explanation. Not right now.' She looked at him, clearly troubled. 'If our assumptions were correct, then we should have changed position but not direction. We should have moved in a straight line, a Euclidean straight line, despite the relativistic curve of space-time, because we weren't in space-time, you see. There may be a mistake in the programming of the computer - or a mistake in our assumptions. I hope the former. That can be corrected easily.'



Five hours passed. Wendel came in, rubbing her eyes. Fisher looked up uncomfortably. He had been viewing a film, but had lost interest. He had then watched the stars, allowing the patterns to hypnotize him, like anesthesia.



He said, 'Well, Tessa?'



'Nothing wrong with the programming, Crile.'



'Then the assumptions must be wrong?'



'Yes, but in what way? There are an infinite number of assumptions we might make. Which are correct? We can't try them one after another. We'd never finish, and we'd be hopelessly lost.'



Silence fell between them for a while and then Wendel said, 'If it had been the programming, it would have been a stupid mistake. We would have corrected it, without learning anything, but we'd have been safe. But now, if we must go back to fundamentals, we have a chance of discovering something really important, but if we fail, we may never find our way back.'



She snatched at Fisher's hand. 'Do you understand, Crile? Something is wrong and if we don't find out what, there's no way - except sheer incredible accident - that will allow us to find our way home. No matter how we try, we may continue to end up in the wrong place, and find ourselves steadily wronger and wronger. Which means death eventually, when our cycling fails, or our power supply peters out, or deep despair drains away our ability to live. And it's I who've done this to you. But the real tragedy would be the loss of a dream. If we don't come back, they'll never know if the ship was successful at all. They might conclude the transition was fatal and they might never try again.'



'But they must if they expect to escape from Earth.'



'They may give up; they may sit cowering, waiting for the Neighbor Star to complete its approach and pass on, and dying bit by bit.' She looked up, her eyes blinking rapidly, her face looking terribly tired. 'And it would be the end of your dream, too, Crile.'



Crile's lips tightened, and he said nothing.



Almost timidly, Wendel said, 'But for years now, Crile, you've had me. If your daughter - your dream - is gone, was I enough?'



'I might ask: If superluminal flight is gone, was I enough?'



There seemed no easy answer on either side, but then Wendel said, 'You're second-best, Crile, but it has been a good second-best. Thank you.'



Fisher stirred. 'You speak for me, too, Tessa, something I wouldn't have believed at the start. If I had never had a daughter, there would have only been you. I almost wish-'



'Don't wish that. Second-best is enough.'



And they held hands. Quietly. And gazed out at the stars.



Until Merry Blankowitz poked her face through the doorway. 'Captain Wendel, Wu has an idea. He said he had it all along, but was reluctant to mention it.'



Wendel started to her feet. 'Why was he reluctant?'



'He said he once suggested the possibility to you, and you told him not to be a fool.'



'Did I? And what has convinced him that I'm never wrong? I'll listen to it now and if it's a good idea, I'll break his neck for not forcing it on me earlier.'



And she hurried out.



72



Fisher could only wait during the day and a half that followed. They all ate together as they always did, but silently. Fisher did not know if any of them slept. He slept only in snatches, and woke to renewed despair.



How long can we go on like this? he thought on the second day, as he looked at the beauty of that unattainable bright dot in the sky that, so brief a time ago, had warmed him and lighted his way on Earth.



Sooner or later, they would die. Modern space technology would prolong life. Recycling was quite efficient. Even food would last a long time if they were willing to accept the tasteless algae cake they would end up with. The micro-fusion motors would dribble out energy for a long time, too. But surely no-one would want to prolong life through the full time that the ship would make possible.



With a lingering, dragging, hopeless, lonely death finally certain, the rational way out would be to use the adjustable de-metabolizers.



That was the preferred method for suicide on Earth; why should it not be onboard ship as well? You could - if you wished - adjust the dose for a full day of reasonably normal life, live it out as joyously as you could - a known last day. At the end of the day, you would grow naturally sleepy. You would yawn and release your hold on wakefulness, passing into a peaceful sleep of restful dreams. The sleep would slowly deepen, the dreams would slowly fade, and you would not wake up. No kinder death had ever been invented.



And then, Tessa, just before 5 p.m., ship-time, on the second day after the transition that had curved instead of being straight, burst into the room. Her eyes were wild and she was breathing hard. Her dark hair, which, in the last year had become liberally salted with gray, was mussed.



Fisher rose in consternation. 'Bad?'



'No, good!' she said, throwing herself into a chair rather than sitting down.



Fisher wasn't sure he had heard correctly, wasn't sure that perhaps she might only have been speaking ironically. He stared at her and watched her as she visibly gathered herself together.



'Good,' she repeated. 'Very good! Extraordinary! Crile, you're looking at an idiot. I don't suppose I'll ever recover from this.'



'Well, what happened?'



'Chao-Li Wu had the answer. He had it all along. He told me. I remember him telling me. Months ago. Maybe a year ago. I dismissed it. I didn't even listen, really.' She paused to catch her breath. Her excitement had completely disoriented the natural rhythm of her speech.



She said, 'The trouble was that I thought of myself as the world authority on superluminal flight, and was convinced that no-one could possibly tell me anything I didn't know or hadn't thought of. And if someone did suggest something that seemed strange to me, the idea was simply wrong, and, presumably, idiotic. Do you know what I mean?'



Fisher said grimly, 'I've met people like that.'



'Everyone's like that, now and then,' said Wendel, 'given certain conditions. I suppose aging scientists are particularly like that. That's why the daring young revolutionaries of science become old fossils after a few decades. Their imaginations harden with encrusted self-love and that's their end. It is now my end... But enough of that. It took us over a day to really work it out, to adjust the equations, to program the computer and set up the necessary simulations, to go down blind alleys and catch ourselves. It should have taken a week, but we were all driving each other like maniacs.'



Wendel paused here, as if to catch her breath. Fisher waited for her to continue, nodding encouragement as he reached out to grasp her hand.



'This is complex,' she continued. 'Let me try to explain. Look- We go from one point in space through hyperspace to another point in space in zero time. But there's a path we take to do that, and it's a different path each time, depending on the starting and ending points. We don't observe the path, we don't experience it, we don't actually follow it in space-time fashion. It exists in a rather incomprehensible way. It's what we call a "virtual path". I worked out that concept myself.'



'If you don't observe it, and don't experience it, how do you know it's there?'



'Because it can be calculated by the equations we use to describe the motion through hyperspace. The equations give us the path.'



'How can you possibly know that the equations are describing anything that has actual reality? It could be just - mathematics.'



'It could be. I thought it was. I ignored it. It was Wu who suggested it might have significance - maybe a year ago - and like a full-grown idiot, I dismissed it. A virtual path, I said, had merely virtual existence. If it couldn't be measured, it was outside the realm of science. I was so shortsighted. I can't endure myself when I think of it.'



'All right. Suppose the virtual path has some sort of existence. What then?'



'In that case, if the virtual path is drawn near a sizable body, the ship experiences gravitational effects. That was the first breathtakingly true and useful new concept - that gravitation can make itself felt along the virtual path.' Wendel shook her fist angrily. 'I saw that myself, in a way, but I reasoned that since a ship would be moving at many times the speed of light, gravitation would have insufficient time to make itself felt to any measurable extent. Travel would therefore be, by my assumption, in a Euclidean straight line.'



'But it wasn't.'



'Obviously not. And Wu explained it. Imagine that the speed of light is a zero point. All speeds less than that of light would have negative magnitude, and all speeds gre.ater than that of light would have positive magnitude. In the ordinary Universe we live in, therefore, all speeds would be negative, by that mathematical convention, and, in fact, must be negative.



'Now, the Universe is built on principles of symmetry. If something as fundamental as speed of movement is always negative, then something else, just as fundamental, ought to be always positive, and Wu suggested that that something else was gravitation. In the ordinary Universe, it is always an attraction. Every object with mass attracts every other object with mass.



'However, if something goes at a superluminal speed - that is, faster than light - then its speed is positive and the other something that was positive has to become negative. At superluminal speed, in other words, gravitation is a repulsive force. Every object with mass repels every other object with mass. Wu suggested that to me a long time ago and I wouldn't listen. His words just bounced off my eardrums.'



Crile said, 'But what's the difference, Tessa? When we're going at enormous superluminal speeds, and gravitational attraction doesn't have time to affect our motion, neither would gravitational repulsion.'



'Ah, that's not so, Crile. That's the beauty of it. That reverses, too. In the ordinary Universe of negative speeds, the faster the speed relative to an attractive body, the less gravitational attraction affects the direction of movement. In the Universe of positive speeds, hyper-space, the faster we go relative to a repulsive body, the more gravitational repulsion affects the direction of movement. That makes no sense to us, since we're used to the situation as it exists in the ordinary Universe, but once you are forced to change signs from plus to minus and vice versa, you find these things falling into place.'



'Mathematically. But how much can you trust the equations?'



'You match your calculations against the facts. Gravitational attraction is the weakest of all the forces and so is the gravitational repulsion along the virtual paths. Within the ship and within us, every particle repels all other particles while we are in hyperspace, but that repulsion can do nothing against the other forces that hold it together and have not changed signs. However, our virtual path from Station Four to here carried us close to Jupiter. Its repulsion along the virtual hyperspatial path was just as intense as its attraction would have been along a nonvirtual spatial path.



'We calculated how Jupiter's gravitational repulsion would affect our path through hyperspace, and that path curved exactly as it had been observed to do. In other words, Wu's modification of my equations not only simplifies them, but it makes them work.'



Fisher said, 'And did you break Wu's neck, Tessa, as you promised you would?'



Wendel laughed, remembering her threat. 'No, I didn't. Actually, I kissed him.'



'I don't blame you.'



'Of course, it's more important now than ever that we get back safely, Crile. This advance in superluminal flight must be reported, and Wu must be properly honored. He built on my work, I admit, but he went on to do what I might never have thought to do. I mean, consider the consequences.'



'I can see them,' said Fisher.



'No, you can't,' said Wendel sharply. 'Now, listen to me. Rotor had no problems with gravitation because they merely skimmed the speed of light - a little below it at some times, a little above it at others - so that gravitational effects, whether positive or negative, attractive or repulsive, had immeasurably small effects on them. It was our own true superluminal flights at many times the speed of light that makes it imperative to take gravitational repulsion into account. My own equations are useless. They will get ships through hyperspace, but not in the right direction. And that's not all.



'I have always thought that there was a certain unavoidable danger in emerging from hyperspace - the second half of the transition. What if you merge into an already existing object? There would be a fantastic explosion that would destroy the ship and everything in it in a trillionth of a trillionth of a second.



'Naturally, we're not going to end up inside a star because we know where the stars are located and can avoid them. In time, we might even know where a star's planets are and avoid them, too. But there are asteroids by the tens of thousands and comets by the tens of billions in the neighborhood of every star. If we end up overlapping one of those, that would still be deadly.



'The only thing that would save us, in the situation as I had thought it to be before today, is the laws of chance. Space is so huge that the chance of striking any object larger than an atom or, at most, a grain of dust is extraordinarily small. Still, given enough trips through hyperspace, the overlapping of matter is a catastrophe just waiting to happen.



'But under conditions as we now know them to be, the chances are zero. Our ship and any sizable object would repel each other and tend to move apart. We are not likely to run afoul of anything deadly. They would all automatically move out of our path.'



Fisher scratched at his forehead. 'Wouldn't we move out of our path, too? Won't that upset our course unexpectedly?'



'Yes, but the small objects we are likely to encounter will alter our path in very limited fashion and we could easily make it up - a small price to pay for safety.'



Wendel took a deep breath and stretched luxuriantly. 'I feel great. What a sensation all this will make when we get back to Earth.'



Fisher chuckled. 'You know, Tessa, before you came in, I was building a morbid picture in my head of our being irretrievably lost; of our ship wandering for ever, with five dead bodies aboard; of its being found someday by intelligent beings who would mourn the obvious space tragedy-'



'Well, it won't happen, you can count on that, my dear,' said Wendel, smiling, and they embraced.