Contact

CHAPTER 19 Naked Singularity

THEY WERE falling. The pentagonal panels of the dodecahedron had become transparent. So had the roof and the floor. Above and below she could make out the organosilicate lacework and the implanted erbium dowels, which seemed to be stirring. All three benzels had disappeared. The dodecahedron plunged, racing down a long dark tunnel just broad enough to permit its passage. The acceleration seemed somewhere around one g. As a result, Ellic, facing forward, was pressed backward in her chair, while Devi, opposite her, was bending slightly at the waist. Perhaps they should have added seat belts.

It was hard not to entertain the thought that they had plunged into the mantle of the Earth, bound for its core of molten iron. Or maybe they were on their way straight to… She tried to imagine this improbable conveyance as a ferryboat upon the River Styx.

There was a texture to the tunnel walls, from which she could sense their speed. The patterns were irregular soft-edged mottlings, nothing with a well-defined form. The walls were not memorable for their appearance, only for their function. Even a few hundred kilometers beneath the Earth's surface the rocks would be glowing with red heat. There was no hint of that. No minor demons were managing the traffic, and no cupboards with jars of marmalade were in evidence.

Every now and then a forward vertex of the dodecahedron would brush the wall, and flakes of an unknown material would be scraped off. The dodec itself seemed unaffected. Soon, quite a cloud of fine particles was following them. Every time the dodecahedron touched the wall, she could sense an undulation, as if something soft had retreated to lessen the impact. The faint yellow lighting was diffuse, uniform.

Occasionally the tunnel would swerve gently, and the dodec would obligingly follow the curvature. Nothing, so far as she could see, was headed towardthem. At these speeds, even a collision with a sparrow would produce a devastating explosion. Or what if this was anendless fall into a bottomless well? She could feel a continuous physical anxiety in the pit of her stomach. Even so, she entertained no second thoughts.

Black hole, she thought. Black hole. I'm falling through the event horizon of a black hole toward the dread singularity. Or maybe this isn't a black hole and I'm headed toward a naked singularity. That's what the physicists called it, a naked singularity. Near a singularity, causality could be violated, effects could precede causes, time could flow backward, and you were unlikely to survive, much less remember the experience. For a rotating black hole, she dredged up from her studies years before, there was not a point but a ring singularity or something still more complex to be avoided. Black holes were nasty. The gravitational tidal forces were so great that you would be stretched into a long thin thread if you were so careless as to fall in. You would also be crushed laterally. Happily, there was no sign of any of this. Through the gray transparent surfaces that were now the ceiling and floor, she could see a great flurry of activity. The organosilicate matrix was collapsing on itself in some places and unfolding in others; the embedded erbium dowels were spinning and tumbling. Everything inside the dodec—including herself and her companions— looked quite ordinary. Well, maybe a bit excited. But they were not yet long thin threads.

These were idle ruminations, she knew. The physics of black holes was not her field. Anyway, she could not understand how this could have anything to do with black holes, which were either primordial—made during the origin of the universe—or produced in a later epoch by the collapse of a star more massive than the Sun. Then, the gravity would be so strong that—except for quantum effects—even light could not escape, although the gravitational field certainly would remain. Hence “black,” hence “hole.” But they hadn't “collapsed a star, and she couldn't see any way in which they had captured a primordial blackhole. Anyway, no one knew where the nearest primordial black hole might be hiding. They had only built the Machine and spun up the benzels.

She glanced over to Eda, who was figuring something on a small computer. By bone conduction, she could feel as well as hear a low-pitched roaring every time the dodec scraped the wall, and she raised her voice to be heard. “Do you understand what's going on?”

“Not at all,” he shouted back. “I can almost prove this can't be happening. Do you know the BoyerLindquist coordinates?”

“No, sorry.” “I'll explain it to you later.” She was glad he thought there would be a “later.” Ellie felt the deceleration before she could see it, as if they had been on the downslope of a roller coaster, had leveled out, and now were slowly climbing. Just before the deceleration set in, the tunnel had made a complex sequence of bobs and weaves. There was no perceptible change either in the color or in the brightness of the surrounding light. She picked up her camera, switched to the long-focal-length lens, and looked as far ahead of her as she could. She could see only to the next jag in the tortuous path. Magnified, the texture of the wall seemed intricate, irregular, and, just for a moment, faintly self-luminous.

The dodecahedron had slowed to a comparative crawl. No end to the tunnel was in sight. She wondered if they would make it to wherever they were going. Perhaps the designers had miscalculated. Maybe the Machine had been built imperfectly, just a little bit off; perhaps what had seemed on Hokkaido an acceptable technological imperfection would doom their mission to failure here in… in wherever this was. Or, glancing at the cloud of fine particles following and occasionally overtaking them, she thought maybe they had bumped into the walls one time too often and lost more momentum than had been allowed for in the design. The space between the dodec and the walls seemed very narrow now. Perhaps they would find themselves stuck fast in this never-never land and languish until theoxygen ran out. Could the Vegans have gone to all this trouble and forgotten that we need to breathe? Hadn't they noticed all those shouting Nazis?Vaygay and Eda were deep in the arcana of gravitational physics—twistors, renormalization of ghost propagators, time-like Killing vectors, non-Abelian gauge invariance, geodesic refocusing, elevendimensional Kaluza-Klein treatments of supergravity, and, of course, Eda's own and quite different superunification. You could tell at a glance that an explanation was not readily within their grasp. She guessed that in another few hours the two physicists would make some progress on the problem.

Superunification embraced virtually all scales and aspects of physics known on Earth. It was hard to believe that this… tunnel was not itself some hitherto unrealized solution of the Eda Field Equations.

Vaygay asked, “Did anyone see a naked singularity?”

“I don't know what one looks like,” Devi replied. “I beg your pardon. It probably wouldn't be naked.

Did you sense any causality inversion, anything bizarre—really crazy—maybe about how you were thinking, anything like scrambled eggs reassembling themselves into whites and yolks…?”

Devi looked at Vaygay through narrowed lids. “It's okay,” Ellie quickly interjected. Vaygay's a little excited, she added to herself. “These are genuine questions about black holes. They only sound crazy.”

“No,” replied Devi slowly, “except for the question itself.” But then she brightened. “In fact it was a marvelous ride.”

They all agreed. Vaygay was elated.

“This is a very strong version of cosmic censorship,” he was saying. “Singularities are invisible even inside black holes.”

“Vaygay is only joking,” Eda added. “Once you're inside the event horizon, there is no way to escape the black hole singularity.”

Despite Ellie's reassurance, Devi was glancing dubiously at both Vaygay and Eda. Physicists had to invent wordsand phrases for concepts far removed from everyday experience. It was their fashion to avoid pure neologisms and instead to evoke, even if feebly, some analogous commonplace. The alternative was to name discoveries and equations after one another. This they did also. But if you didn't know it was physics they were talking, you might very well worry about them.

She stood up to cross over to Devi, but at the same moment Xi roused them with a shout. The walls of the tunnel were undulating, closing in on the dodecahedron, squeezing it forward. A nice rhythm was being established. Every time the dodec would slow almost to a halt, it was given another squeeze by the walls.

She felt a slight motion sickness rising in her. In some places it was tough going, the walls working hard, waves of contraction and expansion rippling down the tunnel. Elsewhere, especially on the straightaways, they would fairly skip along.

A great distance away, Ellie made out a dim point of light, slowly growing in intensity. A blue-white radiance began flooding the inside of the dodecahedron. She could see it glint off the black erbium cylinders, now almost stationary. Although the journey seemed to have taken only ten or fifteen minutes, the contrast between the subdued, restrained ambient light for most of the trip and the swelling brilliance ahead was striking. They were rushing toward it, shooting up the tunnel, and then erupting into what seemed to be ordinary space. Before them was a huge blue-white sun, disconcertingly close. Ellie knew in an instant it was Vega.

She was reluctant to look at it directly through the long-focal-length lens; this was foolhardy even for the Sun, a cooler and dimmer star. But she produced a piece of white paper, moved it so it was in the focal plane of the long lens and projected a bright image of the star. She could see two great sunspot groups and a hint, she thought, a shadow, of some of the material in the ring plane. Putting down the camera, she held her hand at arm's length, palm outward,to just cover the disk of Vega, and was rewarded by seeing a brilliant extended corona around the star; it had been invisible before, washed out in Vega's glare.

Palm still outstretched, she examined the ring of debris that surrounded the star. The nature of the Vega system had been the subject of worldwide debate ever since receipt of the prime number Message. Acting on behalf of the astronomical community of the planet Earth, she hoped she was not making any serious mistakes. She videotaped at a variety of f/stops and frame speeds. They had emerged almost in the ring plane, in a debris-free circumstellar gap. The ring was extremely thin compared with its vast lateral dimensions. She could make out faint color gradations within the rings, but none of the individual ring particles. If they were at all like the rings of Saturn, a particle a few meters across would be a giant. Perhaps the Vegan rings were composed entirely of specks of dust, clods of rock, shards of ice.

She turned around to look back at where they had emerged and saw a field of black—a circular blackness, blacker than velvet, blacker than the night sky. It eclipsed that leeward portion of the Vega ring system which was otherwise—where not obscured by this somber apparition—clearly visible. As she peered through the lens more closely, she thought she could see faint erratic flashes of light from its very center.

Hawking radiation? No, its wavelength would be much too long. Or light from the planet Earth still rushing down the tube? On the other side of that blackness was Hokkaido.

Planets. Where were the planets? She scanned the ring plane with the long-focal-length lens, searching for embedded planets—or at least for the home of the beings who had broadcast the Message. In each break in the rings she looked for a shepherding world whose gravitational influence had cleared the lanes of dust.

But she could find nothing.

“You can't find any planets?” Xi asked. “Nothing. There's a few big comets in close. I can see the tails.

But nothing that looks like a planet. There must bethousands of separate rings. As far as I can tell, they're all made of debris. The black hole seems to have cleared out a big gap in the rings. That's where we are right now, slowly orbiting Vega. The system is very young—only a few hundred million years old—and some astronomers thought it was too soon for there to be planets. But then where did the transmission come from?”

“Maybe this isn't Vega,” Vaygay offered. “Maybe our radio signal comes from Vega, but the tunnel goes to another star system.”

“Maybe, but it's a funny coincidence that your other star should have roughly the same color temperature as Vega— look, yon can see it's bluish—and the same kind of debris system. It's true, I can't check this out from the constellations because of the glare. I'd still give you ten-to-one odds this is Vega.”

“But then where are they?” Devi asked. Xi, whose eyesight was acute, was staring up—through the organosilicate matrix, out the transparent pentagonal panels, into the sky far above the ring plane. He said nothing, and Ellie followed his gaze. There was something there, all right, gloaming in the sunlight and with a perceptible angular size. She looked through the long lens. It was some vast irregular polyhedron, each of its faces covered with… a kind of circle? Disk? Dish? Bowl?" Here, Qiaomu, look through here. Tell us what you see.”

“Yes, I see. Your counterparts… radio telescopes. Thousands of them, I suppose, pointing in many directions. It is not a world. It is only a device.”

They took turns using the long lens. She concealed her impatience to look again. The fundamental nature of a radio telescope was more or less specified by the physics of radio waves, but she found herself disappointed that a civilization able to make, or even just use, black holes for some kind of hyperrelativistic transport would still be using radio telescopes of recognizable design, no matter how massive the scale. It seemed backward of the Vegans… unimaginative. She understood the advantage of putting the telescopes in polar orbit around the star, safe except for twice each revolution from collisions with ring plane debris.

But radio telescopes pointing all over the sky—thousands of them—suggested some comprehensive sky survey, an Argus in earnest. Innumerable candidate worlds were being watched for television transmission, military radar, and perhaps other varieties of early radio transmission unknown on Earth. Did they find such signals often, she wondered, or was the Earth their first success in a million years of looking? There was no sign of a welcoming committee. Was a delegation from the provinces so unremarkable that no one had been assigned even to note their arrival?When the lens was returned to her she took great care with focus, f/stop, and exposure time. She wanted a permanent record, to show the National Science Foundation what really serious radio astronomy was like. She wished there were a way to determine the size of the polyhedral world. The telescopes covered it like barnacles on a whaler. A radio telescope in zero g could be essentially any size. After the pictures were developed, she would be able to determine the angular size (maybe a few minutes of arc), but the linear size, the real dimensions, that was impossible to figure out unless you knew how far away the thing was. Nevertheless she sensed it was vast.

“If there are no worlds here,” Xi was saying, “then there are no Vegans. No one lives here. Vega is only a guard-house, a place for the border patrol to warm their hands.”

“Those radio telescopes”—he glanced upward—”are the watchtowers of the Great Wall. If you are limited by the speed of light, it is difficult to hold a galactic empire together. You order the garrison to put down a rebellion. Ten thousand years later you find out what happened. Not good. Too slow. So you give autonomy to the garrison commanders. Then, no more empire. But those”—and now he gestured at the receding blot covering the sky behind them—”those are imperial roads. Persia had them. Romehad them.

China had them. Then you are not restricted to the speed of light. With roads you can hold an empire together.”

But Eda, lost in thought, was shaking his bead. Something about the physics was bothering him.

The black hole, if that was what it really was, could now be seen orbiting Vega in a broad lane entirely clear of debris; both inner and outer rings gave it wide berth. It was hard to believe how black it was.

As she took short video pans of the debris ring before her, she wondered whether it would someday form its own planetary system, the particles colliding, sticking, growing ever larger, gravitational condensations taking place until at last only a few large worlds orbited the star. It was very like the picture astronomers had of the origin of the planets around the Sun four and a half billion years ago. She could now make out inhomogeneities in the rings, places with a discernible bulge where some debris had apparently accreted together.

The motion of the black hole around Vega was creating a visible ripple in the bands of debris immediately adjacent The dodecahedron was doubtless producing some more modest wake. She wondered if these gravitational perturbations, these spreading rarefactions and condensations, would have any long-term consequence, changing the pattern of subsequent planetary formation. If so, then the very existence of some planet billions of years in the future might be due to the black hole and the Machine… and therefore to the Message, and therefore to Project Argus. She knew she was overpersonalizing; bad she never lived, some other radio astronomer would surely have received the Message, but earlier, or later. The Machine would have been activated at a different moment and the dodec would have found its way here in some other time.

So some future planet in this system might still owe its existence to her. Then, by symmetry, she had snatched out of existence some other world that was destined to form bad she never lived. It was vaguely burdensome, being responsible by your innocent actions for the fates of unknown worlds.

She attempted a panning shot, beginning inside the dodecahedron, then out to the struts joining the transparent pentagonal panels, and beyond to the gap in the debris rings in which they, along with the black hole, were orbiting. She followed the gap, flanked by two bluish rings, further and further from her. There was something a little odd up ahead, a kind of bowing in the adjacent inner ring.

“Qiaomu,” she said, handing him the long lens, “look over there. Tell me what you sec.”

“Where?”

She pointed again. After a moment he had found it. She could tell because of his slight but quite unmistakable intake of breath. “Another black hole,” he said. “Much bigger.”

They were falling again. This time the tunnel was more commodious, and they were making better time.

“That's it?” Ellie found herself shouting at Devi. “They take us to Vega to show off their black holes.

They give us a look at their radio telescopes from a thousand kilometers away. We spend ten minutes there, and they pop us into another black hole and ship us back to Earth. That's why we spent two trillion dollars?”

“Maybe we're beside the point,” Lunacharsky was saying. “Maybe the only real point was to plug themselves into the Earth.”

She imagined nocturnal excavations beneath the gates of Troy.

Eda, fingers of both hands outspread, was making a calming gesture. “Wait and see,” he said. “This is a different tunnel. Why should you think it goes back to Earth?”

“Vega's not where we're intended to go?” Devi asked. “The experimental method. Let's see where we pop out next.” In this tunnel there was less scraping of the walls andfewer undulations. Eda and Vaygay were debating a space-time diagram they had drawn in Kruskal-Szekeres coordinates. Ellie had no idea what they were talking about. The deceleration stage, the part of the passage that felt uphill, was still disconcerting.

This time the light at the end of the tunnel was orange. They emerged at a considerable speed into the system of a contact binary, two suns touching. The outer layers of a swollen elderly red giant star were pouring onto the photosphere of a vigorous middle-aged yellow dwarf, something like the Sun. The zone of contact between the two stars was brilliant. She looked for debris rings or planets or orbiting radio observatories, but could find none. That doesn't mean very much, she told herself. These systems could have a fair number of planets and I'd never know it with this dinky long lens. She projected the double sun onto the piece of paper and photographed the image with a short-focal-length lens.

Because there were no rings, there was less scattered light in this system than around Vega; with the wide-angle lens she was able, after a bit of searching, to recognize a constellation that sufficiently resembled the Big Dipper. But she had difficulty recognizing the other constellations. Since the bright stars in the Big Dipper are a few hundred light-years from Earth, she concluded that they had not jumped more than a few hundred light-years. She told this to Eda and asked him what he thought. “What do I think? I think this is an Underground.”

“An Underground?”

She recalled her sensation of falling, into the depths of Hell it had seemed for a moment, just after the Machine had been activated.

“A Metro. A subway. These are the stations. The stops. Vega and this system and others. Passengers get on and off at the stops. You change trains here.”

He gestured at the contact binary, and she noticed that his hand cast two shadows, one anti-yellow and the other anti-red, like in—it was the only image that came to mind—a discotheque.

“But we, we cannot get off,” Eda continued. “We are in a closed railway car. We're headed for the terminal, the end of the line.”

Drumlin had called such speculations Fantasyland, and this was—so far as she knew—the first time Eda had succumbed to the temptation.

Of the Five, she was the only observational astronomer, even though her specialty was not in the optical spectrum. She felt it her responsibility to accumulate as much data as possible, in the tunnels and in the ordinary four-dimensional space-time into which they would periodically emerge. The presumptive black hole from which they exited would always be in orbit around some star or multiple-star system. They were always in pairs, always two of them sharing a similar orbit—one from which they were ejected, and another into which they fell. No two systems were closely similar. None was very like the solar system. All provided instructive astronomical insights. Not one of them exhibited anything like an artifact—a second dodecahedron, or some vast engineering project to take apart a world and reassemble it into what Xi had called a device.

At this time they emerged near a star visibly changing its brightness (she could tell from the progression of f/stops required)—perhaps it was one of the RR Lyrae stars; next was a quintuple system; then a feebly luminous brown dwarf. Some were in open space, some were embedded in nebulosity, surrounded by glowing molecular clouds.

She recalled the warning “This will be deducted from your share in Paradise.” Nothing had been deducted from hers. Despite a conscious effort to retain a professional calm, her heart soared at this profusion of suns. She hoped that every one of them was a home to someone. Or would be one day.

But after the fourth jump she began to worry. Subjec-tively, and by her wristwatch, it felt something like an hour since they had “left” Hokkaido. If this took much longer, the absence of amenities would be felt.

Probably there wereaspects of human physiology that could not be deduced even after attentive television viewing by a very advanced civilization.

And if the extraterrestrials were so smart, why were they putting us through so many little jumps? All right, maybe the hop from Earth used rudimentary equipment because only primitives were working one side of the tunnel. But after Vega? Why couldn't they jump us directly to wherever the dodec was going?Each time she came barreling out of a tunnel, she was expectant. What wonders had they in store for her next? It put her in mind of a very upscale amusement park, and she found herself imagining Hadden peering down his telescope at Hokkaido the moment the Machine had been activated.

As glorious as the vistas offered by the Message makers were, and however much she enjoyed a kind of proprietary mastery of the subject as she explained some aspect of stellar evolution to the others, she was after a time disappointed. She had to work to track the feeling down. Soon she had it: The extraterrestrials were boasting. It was unseemly. It betrayed some defect of character.

As they plunged down still another tunnel, this one broader and more tortuous than the others, Lunacharsky asked Eda to guess why the subway stops were put in such unpromising star systems. “Why not around a single star, a young star in good health and with no debris?”

“Because,” Eda replied, “—of course, I am only guessing as you ask—because all such systems are inhabited…”

“And they don't want the tourists scaring the natives,” Sukhavati shot back. Eda smiled. “Or the other way around.”

“But that's what you mean, isn't it? There's some sort of ethic of noninterference with primitive planets.

They know that every now and then some of the primitives might use the subway…”

“And they're pretty sure of the primitives,” Ellie continued the thought, “but they can't be absolutely sure. After all, primitives are primitive. So you let them ride only onsubways that go to the sticks. The builders must be a very cautious bunch. But then why did they send us a local train and not an express?”

“Probably it's too hard to build an express tunnel,” said Xi, years of digging experience behind him.

Ellie thought of the Honshu-Hokkaido Tunnel, one of the prides of civil engineering on Earth, all of fifty-one kilometers long.

A few of the turns were quite steep now. She thought about her Thunderbird, and then she thought about getting sick. She decided she would fight it as long as she could. The dodecahedron had not been equipped with airsickness bags.

Abruptly they were on a straightaway, and then the sky was full of stars. Everywhere she looked there were stars, not the paltry scattering of a few thousand still occasionally known to naked-eye observers on Earth, but a vast multitude—many almost touching their nearest neighbors it seemed—surrounding her in every direction, many of them tinted yellow or blue or red, especially red. The sky was blazing with nearby suns. She could make out an immense spiraling cloud of dust, an accretion disk apparently flowing into a black hole of staggering proportions, out of which flashes of radiation were coming like heat lightning on a summer's night. If this was the center of the Galaxy, as she suspected, it would be bathed in synchrotron radiation. She hoped the extraterrestrials had remembered how frail humans were.

And swimming into her field of view as the dodec rotated was… a prodigy, a wonder, a miracle. They were upon it almost before they knew it. It filled half the sky. Now they were flying over it. On its surface were hundreds, perhaps thousands, of illuminated doorways, each a different shape. Many were polygonal or circular or with an elliptical cross section, some had projecting appendages or a sequence of partly overlapping off-center circles. She realized they were docking ports, thousands of different docking ports— some perhaps only meters in size, others clearly kilometers across, or larger. Every one of them, she decided, was the template of some interstellar machine like this one. Bigcreatures in serious machines had imposing entry ports. Little creatures, like us, had tiny ports. It was a democratic arrangement, with no hint of particularly privileged civilizations. The diversity of ports suggested few social distinctions among the sundry civilizations, but it implied a breathtaking diversity of beings and cultures. Talk about Grand Central Station! she thought.

The vision of a populated Galaxy, of a universe spilling over with life and intelligence, made her want to cry for joy.

They were approaching a yellow-lit port which, Elbe could see, was the exact template of the dodecahedron in which they were riding. She watched a nearby docking port, where something the size of the dodecahedron and shaped approximately like a starfish was gently insinuating itself onto its template.

She glanced left and right, up and down, at the almost imperceptible curvature of this great Station situated at what she guessed was the center of the Milky Way. What a vindication for the human species, invited here at last! There's hope for us, she thought. There's hope! “Well, it isn't Bridgeport.”

She said this aloud as the docking maneuver completed itself in perfect silence.