Hans Rebka had arrived on Dobelle disoriented and angry. Darya Lang, following his subluminal path just three days later on her run from the final Bose Transition Point to the Opal spaceport, did not have room for anger.
She was nervous; more than nervous, she was scared.
For more than half her life she had been a research scientist, an archeologist whose mind was most comfortable seven million years in the past. She had performed the most complete survey of Builder artifacts, locating, listing, comparing, and cataloging every one so far discovered in Fourth Alliance territory, and noting the precise times of any changes in their historical appearance or apparent function. But she had done all that passively, from the tranquil harbor of her research office on Sentinel Gate. She might know by heart the coordinates of the twelve hundred-odd artifacts scattered through the whole spiral arm, and she could reel off the current state of knowledge concerning each one. But other than the Sentinel, whose shining bulk was visible from the surface of her home planet, she had never seen one.
And now she was approaching Dobelle—when no one else had even wanted her to go.
"Why shouldn't I go?" she had asked when the Committee of the Fourth Alliance on Miranda sent their representative to her. She was trembling with tension and annoyance. "The anomaly is mine, if it's anyone's. I discovered it."
"That is true." Legate Pereira was a small, patient woman with nut-brown skin and golden eyes. She did not appear intimidating, but Darya Lang found it hard to face her. "And since you reported it, we have confirmed it for every Artifact. No one is trying to deny you full credit for your discovery. And we all admit that you are our expert on the Builders, and are most knowledgeable about their technology—"
"No one understands Builder technology!" Even in her irritation, Darya could not let that pass.
"Most is a comparative term. No one in the Alliance knows more. Since, I repeat, you are most knowledgeable about the technology of the Builders, you are clearly the best-qualified individual to pursue the anomaly's significance." The woman's voice became more gentle. "But at the same time, Professor Lang, you must admit that you have little experience of interstellar travel."
"I have none, and you know it. But everyone, from you to my house-uncle Matra, tells me that interstellar travel offers negligible risk."
The legate sighed. "Professor, it is not the travel we question. Look around you. What do you see?"
Darya raised her head and surveyed the garden. Flowers, vines, trees, the cooing birds, the last rays of evening sunlight throwing dusty shafts of light through the trellis of the bower . . . It was all normal. What was she supposed to see?
"Everything looks fine."
"It is fine. That is my point. You have lived all your life on Sentinel Gate, and this is a garden world. One of the finest, richest, most beautiful planets that we know—far nicer than Miranda, where I live. But you are proposing to go to Quake. To nowhere. To a dingy, dirty, dismal, dangerous world, in the wild hope that you will find there new evidence of the Builders. Can you give me one reason for thinking that Quake has such potential?"
"You know the answer. My discovery provides that reason."
"A statistical anomaly. Do you want to endure misery and discomfort for the sake of statistics?"
"Of course I don't." Darya felt that the other woman was talking down to her, and that was the one thing she could not stand. "No one wants discomfort. Legate Pereira, you admit that no one in the Fourth Alliance has more knowledge of the Builders than I do. Suppose I do not go, and someone else does, and whoever goes in my place fails for lack of knowledge where I might have succeeded. Do you think that I could ever forgive myself?"
Instead of replying, Pereira went to the window and beckoned Darya Lang to her side. She pointed into the slowly darkening sky. The Sentinel gleamed close to the horizon, a shining and striated sphere two hundred million kilometers away and a million kilometers across.
"Suppose I told you that I knew a way to break in through the Sentinel's protective shield and to explore the Pyramid at the center. Would you go with me?"
"Of course. I've studied the Sentinel since I was a child. If I'm right, the Pyramid could contain a library for the Builder sciences—maybe their history, too. But no one knows how to break the shield. We have been trying for a thousand years."
"But suppose we could crack it."
"Then I would want to go."
"And suppose it involved danger and discomfort?"
"I would still want to go."
The legate nodded and sat in silence for a few seconds as the darkness deepened. "Very well,"she said at last. "Professor Lang, you are said to be a logical person, and I like to think that I am, too. If you are willing to run the risks of the Sentinel's shield, and those are unknown risks, then you have a right to endure the lesser risks of Quake. As for travel to the Dobelle system, we humans built the Bose Drive, and we understand exactly how it works. We know how to employ the Bose Network. The experience is frightening at first, but the danger is small. And perhaps if you can use that Network to explore the statistical anomaly that you alone discovered, it will finally provide the tool you need to crack the secret of the Sentinel. I cannot deny that chain of logic. You have the right to make the journey. I will approve your travel request."
"Thank you, Legate Pereira." With the victory, Darya felt a chill that was not caused by the night air. She was passing from pleasant theory to commitment.
"But there is one other thing," Pereira's voice sharpened. "I trust that you have not told anyone outside the Alliance about your discovery of the anomaly?"
"No. Not a person. I sent it only through regular reporting channels. There is no one else here who would care to hear about it, and I wanted—"
"Good. Be sure you keep it that way. For your information, the anomaly is now to be treated as an official secret of the Fourth Alliance."
"Secret! But anyone could perform the same analysis that I did. Why . . ." Lang subsided. If she said that anyone could do the work, she might lose her claim to the anomaly—and the trip to Quake.
The legate stared at her soberly and finally nodded. "Remember, you are about to embark on a journey of more than seven hundred light-years, beyond the borders of the Alliance. In some ways I envy you. It is a journey more than I have ever made. I have nothing more to say, except to give you my good wishes for a safe trip and a successful mission."
Darya could hardly believe that she had won, after weeks of red tape and dithering from the authorities of the Fourth Alliance. And the perils of the Bose Drive had indeed faded, once she was on her way and made her initial step through the Network. The first Transistion was disconcerting, not for the feelings that it introduced but for their absence. The Transition was instantaneous and imperceptible, and that did not seem right. The human brain required some notice that it and the ship that carried it had been transported across a hundred light-years or more. Perhaps a slight shock, Darya thought; a little nausea, maybe, or some feeling of disorientation.
Then at the second and third Transitions that concern vanished, just as Legate Pereira had promised. Darya could take the mysteries of the Bose Drive for granted.
But what did not decrease was her own feeling of inadequacy. She was a bad liar; she always had been. The Dobelle system contained just one structure that dated back to the Builders: the Umbilical. And that was a minor artifact, one whose operations were self-evident even if the controls that governed it remained mysterious. She would never have made so long a journey merely to look at the Umbilical. No one would. And yet that was the Alliance's official rationale for her visit.
Someone was going to ask her why she had done so odd a thing; she just knew it. And nothing in half a lifetime of research work had taught her how to fake things. Her face would give her away.
The sight of Dobelle eased her uneasiness a little. In a universe that she saw as populated by the miracles of the Builders, here was a natural wonder to rival them. Forty or fifty million years earlier the planetary doublet of Quake and Opal had orbited the star Mandel in a near-circular path. That orbit had been stable for billions of years, resisting the gravitational tugs of Mandel's small and remote binary-system partner, Amaranth, and of its two great gas-giant planets, moving in their eccentric orbits five and seven hundred million kilometers farther out. The environment had been tranquil on both members of the Dobelle planetary pair, until a close encounter of the two gas-giants had thrown one of them into a grazing swing-by of Mandel. That unnamed stranger had emerged from its sun-skimming trajectory with a modified path that took it clear out of the stellar system and into the void.
That would have been the end of the story—except that Dobelle lay in the stranger's exit route. The gas-giant had done a complex dance about the doublet planet, moving Quake and Opal closer together while changing their combined orbit to one with a periastron that skimmed much closer to Mandel. Then the stranger had vanished into history. Only Dobelle and the gas-giant called Gargantua remained, their still-changing orbital elements allowing an accurate reconstruction of past events.
Summertide, Dobelle's time of closest approach to Mandel, was just a couple of weeks away. It would be a time, if Darya Lang's analysis was correct, of great significance in the spiral arm. And also in her own life. Her theories would at last be proved true.
Or false.
She went to the port and watched as the ship approached Dobelle. Opal and Quake whirled dizzily around each other in a mad dance, spinning three full turns in a standard day. She could actually see their motion. However, speed was all relative. The ship's rendezvous with the landing field on Opal's Starside sounded difficult, but it was a trivial problem for the navigation computers that would make the rendezvous.
The problems would come not from there, but from the humans who wanted to greet her. The tone of the message permitting her entry to Opal sounded ominous. "Provide the full identification of your sponsor. State in full the proposed length of stay. Give details of expected findings. Explain why the time of your requested visit is critical. Say just why you wish to visit Quake. Provide credit information or nonrefundable advance payment. Signed, Maxwell Perry, Commander."
Were the immigration officials on Opal so hostile to every offworld visitor? Or was her paranoia not paranoia at all, but a well-merited uneasiness?
She was still standing by the port as the ship began its final approach. They were coming in from the direction of Mandel, and she had a fine sunlit view of the doublet. She knew that Opal was only slightly larger than Quake—5,600 kilometers mean radius, compared with Quake's 5,100—but the human eye insisted otherwise. The cloud-covered iridescent ball of Opal, slightly egg-shaped and with its long axis pointing always to its sister world, loomed large. The darker, smaller ovoid of Quake brooded next to it, a smooth-polished heliotrope against the brighter gemstone of its partner. Opal was featureless, but the surface of Quake was full of texture, stippled with patches of deep purple and darkest green. She tried to make out the thread of the Umbilical, but from that distance it was invisible.
Entry to the Dobelle system offered no options. There was only one spaceport, set close to the middle of Opal's Starside hemisphere. There was no spaceport of any kind on Quake. According to her reference texts, safe access to Quake came only via Opal.
Safe access to Quake?
A nice idea, but Darya recalled what she had read of Quake and of Summertide. Maybe the reference texts needed to find different words . . . at least at this time of the year.
The reference files of the Fourth Alliance had even fewer good things to say than Legate Pereira about the worlds controlled by the Phemus Circle. "Remote . . . impoverished . . . backward . . . thinly populated . . . barbaric."
The stars of the Circle lay in a region overlapped by all three major clades of the spiral arm. But in their outward expansions the Fourth Alliance, the Zardalu Communion, and the Cecropia Federation had shown negligible interest in the Phemus Circle. There was nothing there worth buying, bargaining for, or stealing—hardly enough to justify a visit.
Unless one was looking for trouble. Trouble was supposed to be easy to find on any world controlled by the Circle.
Darya Lang stepped out of the ship onto the spongy ground of Opal's Starside spaceport and looked around her with misgiving. The buildings were low and ground-hugging, built of what looked like plaited reeds and dried mud. No one was waiting to greet the ship. Opal was described as metal-poor, wood-poor, and people-poor. All it had was water, and lots of it.
As her shoe sank an inch or two into the soft surface she felt even more uneasy. She had never visited a waterworld, and she knew that instead of hard rock and solid ground beneath her feet, there was only the weak and insubstantial crust of the Sling. Below that was nothing but brackish water, a couple of kilometers deep. The buildings hugged the ground for a good reason. If they were too tall and heavy, they would break through it.
An irrelevant thought came to her: she could not even swim.
The crew of the ship that had brought her were still involved with the final stages of landing procedure. She began to walk toward the nearest building. Two men were finally emerging from it to greet her.
It was not a promising introduction to Opal. Both men were short and thin—Darya Lang was ten centimeters taller than either of them. They were dressed in identical dingy uniforms, with clothes that shared a patched and well-worn look, and from a distance the two might have been taken for brothers, one ten years or so older than the other. Only as she came closer were their differences revealed.
The older man had a friendly, matter-of-fact air to him and a self-confident walk. The faded captain's insignia on his shoulder indicated that he was the senior of the two in rank as well as age. "Darya Lang?" he said as soon as they were within easy speaking distance. He smiled and held out his hand, but not to shake hers. "I'll take your entry forms. I'm Captain Rebka."
Add "brusque" to the list of words describing the inhabitants of the Phemus Circle, she thought. And add "unkempt" and "battered" to Rebka's physical description. The man's face had a dozen scars on it, the most noticeable running in a double line from his left temple to the point of his jaw. And yet the overall effect was not unpleasant—rather the opposite. To her surprise, Darya sensed the indefinable tingle of mutual attraction.
She handed over her papers and made internal excuses for the scars and the grimy uniform. Dirt was only superficial, and maybe Rebka had been through some exceptional misfortune.
Except that the younger man looked just as dirty, and he had his own scars. At some time his neck and one side of his face had been badly burned, with a bungled attempt at reconstructive surgery that would never have been accepted back on Sentinel Gate.
Maybe the burn scars had also left the skin of his face lacking in flexibility. Certainly he had a very different expression from Rebka. Where the captain was breezy in manner and likeable despite his grubbiness and lack of finesse, the other man seemed withdrawn and distant. His face was stiff and expressionless, and he hardly seemed aware of Darya, although she was standing less than two meters from him. And whereas Rebka was clearly in top physical shape, the other had a run-down and unhealthy look, the air of a man who did not eat regular meals or care at all about his own health.
His eyes were at variance with his young face. Dead and disinterested, they were the pale orbs of a man who had withdrawn from the whole universe. He was unlikely to cause Darya any trouble.
Just as she reached that comforting conclusion the face before came alive and the man snapped out, "My name is Perry. Commander Maxwell Perry. Why do you want to visit Quake?"
The question destroyed her composure completely. Coming without the preliminary and traditional courtesies of Alliance introductions, it convinced Darya Lang that these people knew—knew about the anomaly, knew about her role in discovering it, and knew what she was there to seek. She felt her face turning red.
"The—the Umbilical." She had to struggle to find words. "I—I have made a special study of Builder artifacts; it has been my life's work." She paused and cleared her throat. "I have read all that I could find about the Umbilical. But I want to see it for myself and learn how the tethers work on Opal and Quake. And discover how Midway Station controls the Umbilical for the move to space at Summertide." She ran out of breath.
Perry remained expressionless, but Captain Rebka had a little smile on his face. She was sure that he saw right through her every word.
"Professor Lang." He was reading from her entry papers. "We do not discourage visitors. Dobelle needs all the revenue it can get. But this is a dangerous time of year on Opal and Quake."
"I know. I have read about the sea tides on Opal, and the land tides on Quake." She cleared her throat again. "It is not my nature to seek danger." That at least was true, she thought wryly. "I propose to be very careful and take all precautions."
"So you have read about Summertide." Perry turned to Rebka, and Darya Lang detected a tension between the two men. "As have you, Captain Rebka. But reading and experiencing something are not the same. And neither of you seems to realize that Summertide this time will be different from all others in our experience."
"Every time must be different," Rebka said calmly. He was smiling, but Darya Lang could feel the conflict. Rebka was the older and the more senior, but on the issue of Summertide Commander Perry did not accept the other's authority.
"This is exceptional," Perry replied. "We will be taking extraordinary precautions, even on Opal. And as for what may happen on Quake, I cannot begin to guess."
"Even though you have experienced half a dozen Summertides?"
Rebka had lost his smile. The two men faced each other in silence, while Darya looked on. She sensed that the fate of her own mission hung on the argument that they were having.
"The Grand Conjunction," Perry said after a few seconds. And finally Darya had a statement that made sense to her as a scientist.
She had studied the orbital geometry of the Mandel system in detail while working on the Lang catalog of artifacts. She knew that Amaranth, the dwarf companion of Mandel, normally moved so far from the primary that the illumination it provided to Dobelle was little more than starlight. However, once every few thousand years its motion brought it much closer, to less than a billion kilometers of Mandel. Gargantua, the remaining gas-giant planet of the system, moved in the same orbital plane, and it, too, had its own point of close approach to Mandel.
Dobelle's critical time of Summertide usually occurred when Gargantua and Amaranth were both far from Mandel. But all three orbits were in resonance lock. On rare occasions, Amaranth and Gargantua swung in together to Mandel, at a time that coincided with Summertide for Opal and Quake. And then . . .
"The Grand Conjunction," Perry repeated. "When everything lines up at periastron, and the sea tides and land tides on Opal and Quake are as big as they can possibly be. We have no idea how big. The Grand Conjunction happens only once every three hundred and fifty thousand years. The last time was long before humans settled Dobelle. But the next time will happen just thirty-three days from now—less than two standard weeks. No one knows what Summertide will do to Opal and Quake then, but I do know that the tidal forces will be devastating."
Darya looked at the soft ground beneath their feet. She had the terrible feeling that the flimsy mud-raft of living and dead plants was already crumbling under the assault of monstrous tides. No matter what the dangers might be on Quake, surely they were preferable to staying on Opal.
"So wouldn't you all be safer on Quake?" she asked.
Perry shook his head. "The permanent population of Opal is more than a million people. That may seem like nothing for someone like you, from an Alliance world. But it is a lot for a Circle world. My birth planet had less than a quarter of that."
"And mine less than an eighth of it," Rebka said mildly. No one stayed on Teufel who had any way to get off it.
"But do you know the permanent population of Quake?" Perry glared at both of them while Lang wondered how she had ever thought him calm and passionless.
"It is zero," he said after a pause. "Zero! What does that tell you about life on Quake?"
"But there is life on Quake." She had studied the planetary index. "Permanent life."
"There is. But it is not human life, and it could not be. It is native life. No human could survive Quake during Summertide—even a normal Summertide."
Perry was becoming increasingly assertive. Darya knew that her case for visiting Quake was lost. He would deny her access, and she would get no closer to Quake than the Starside spaceport. As she decided that, help came from an unexpected direction.
Rebka turned to Max Perry and pointed a thin finger up to Opal's cloudy skies. "You are probably right, Commander Perry," he said quietly. "But suppose strangers are coming to Dobelle because it will be the Grand Conjunction? We did not consider that possibility when we were examining their applications." He turned to stare at Darya Lang. "Is that your real reason for being here?"
"No. Definitely not." She felt relief at being able to give an honest answer. "I never thought about the Conjunction until Commander Perry mentioned it."
"I believe you." Rebka smiled, and she was suddenly convinced that he did. But she recalled Legate Pereira's words: "Don't trust anyone from the Phemus Circle. They practice survival skills that we in the Alliance have never been forced to learn."
"People's reasons for coming here are not too relevant, of course," he went on. "They don't make Quake any safer." He turned to Perry. "And I feel sure you are right about the dangers of Quake at Summertide. On the other hand, I have a responsibility to maximize the revenues of Dobelle. That's my job. We have no responsibility to protect visitors, beyond a duty to warn them. If they choose to proceed, knowing the risks, that is their option. They are not children."
"They have no notion of what Quake is like at Summertide." Perry's face had turned blotchy white and red. He was overwhelmed by strong emotion. "You have no idea."
"Not yet. But I will have." Rebka's manner changed again. He became a boss who was clearly giving orders. "I agree with you, Commander. It would be irresponsible for Professor Lang to visit Quake—until we are sure of the hazards. But once we do understand them—and can explain them—we have no duty to be overprotective. So you and I will go to Quake, while Professor Lang remains here on Opal."
He turned to Darya. "And when we return . . . well, then, Professor Lang, I will make my decision."
ARTIFACT: SENTINEL
UAC#: 863
Galactic Coordinates: 27,712.863/16,311.031/761.157
Name: Sentinel Star/planet association: Ryders-M/Sentinel Gate
Bose Access Node: G-232 Estimated age: 5.64 ± 0.07 Megayears
Exploration History: Sentinel was discovered in Expansion Year 2649 by human colonists of the trans-Orionic region. First entry attempt, E. 2674, by Bernardo Gullemas and the crew of exploration vessel D-33 of Cyclops class. No survivors. Subsequent approaches attempted E. 2682, E. 2695, E. 2755, E. 2803, E. 2991. No survivors.
Sentinel warning beacon set in place, E.2739; monitoring station established on nearest planet (Sentinel Gate), E. 2762.
Physical Description: Sentinel is a near-spherical inaccessible region, a little less than one million kilometers across. No visible internal energey sources, but Sentinel glows faintly with its own light (absolute magnitude +25) and is visible from every point of the Ryders-M system. The impassable surface of Sentinel readily permits two-way passage of light and radiation of any wavelength, but it reflects all material objects including atomic and subatomic particles. There is photon flux only from the interior, with no particle emission. Laser illumination of the interior is possible, and reveals a variety of structures at the center of the sphere. The most prominent such feature is "The Pyramid," a regular tetrahedral structure which absorbs all light falling onto it. If interior distances within Sentinel have meaning (there is evidence that they do not—see below) then the Pyramid would be approximately ninety kilometers on a side. No increase in temperature of the Pyramid is detectible, even when incident absorbed radiation is at the gigawatt level.
Path length measurements using lasers show that rhe interior of Sentinel is not simply-connected; minimal light travel time across Sentinel is 4.221 minutes, compared with a geodesic travel time of 3.274 seconds for equivalent distance across empty space remote from matter. For light incident normally on the Sentinel "equator" travel times across Sentinel are infinite, or certainly in excess of a thousand years. Red shift and grazing incidence laser beams indicate that no mass is present within Sentinel, a result that is inconsistent with the observed interior structure.
Sentinel holds a precise distance of 22.34a.u. from the Ryders-M primary star, but is not in orbit about it. Gravitational forces and radiation pressure forces either are exactly compensated by some unknown mechanism in Sentinel, or do not act on the structure at all.
Physical Nature of Sentinel: According to Wollaski'i and Drews, Sentinel takes advantage of and is built around a natural anomaly of space-time and possesses only weak physical coupling to the rest of the universe. If so, this is one of only thirty-two Builder artifacts that were created with the use of preexisting and natural features.
Sentinel topology appears to be that of a Ricci-Cartan-Penrose knot in 7-space.
Intended Purpose: Unknown. However, it is conjectured (by analogy with other Builder artifacts, see Entry 311, 465, and 1223) that the Pyramid may possess near-infinite information storage capacity and lifetime. It has therefore been suggested (Lang, E. 4130) that the Pyramid and possibly the whole of Sentinel form a Builder library.
—From the Lang Universal Artifact Catalog, Fourth Edition.