Incandescence

by Greg Egan

  "My name is Ra," Rakesh said.

  "I'm Neb," the farmer replied.

  "I've come from outside the world," Rakesh announced boldly.

  "We have enough workers," Neb explained. "We're not seeking recruits right now."

  "I want to talk with you, that's all."

  "You didn't hear me?" Neb admonished him. "You should return to your own team, or find another one. We have all the workers we need here."

  Neb moved away from him, sifting purposefully through the fungus.

  Rakesh kept trying, but each time he received the same perfunctory response. The fact that he could speak and was roughly the right shape seemed to be enough for the Arkdwellers to treat him as one of their own kind, but having made that categorization they had no interest in his actual words. If the team had been short-handed perhaps they would have sought to recruit him, but it was not, so he was irrelevant. Beyond the curt exchange of greetings that even a stranger merited, conversation served only as an adjunct to social bonding, and they had no need, or wish, to form any kind of bond with him.

  Rakesh stood motionless in the chamber and let the farmers pass him by. Nobody took it upon themself to say a word to him, to ask him where he was from, how he had arrived, what he wanted. A walking scarecrow from beneath the edge of the world was surplus to requirements.

  So be it. These farmers were not the only team in the Ark; there had to be one that would welcome a new recruit.

  Rakesh left the chamber by a tunnel opposite the one he'd come in by. At first there was no one else in sight, but as he ascended deeper into the Ark he started glimpsing people moving in the distance, crossing ahead of him through side tunnels. He thought of running after them, but he'd observed enough of the Arkdwellers' normal behavior to know that the hot pursuit of strangers, followed by begging for recruitment, lay right off the spectrum. The strangeness of his body had not proved to be the icebreaker he'd hoped; eccentric behavior was unlikely to open any more doors.

  He reached a T-junction in the tunnel he'd been following; he took a right turn, since that was the branch that continued to slope upward. Ahead of him was a female Arkdweller, pulling a wheeled cart loaded with animal hides.

  He greeted her, and introduced himself. Her name was Saf, and she proved to be far more responsive than the farmers; when he asked where she was going, she explained that she was carrying the hides to a depot about one shift's journey away.

  "Can I travel with you?" Rakesh asked.

  "Why should I stop you traveling wherever you wish?" she replied.

  Rakesh trudged beside her in silence. He was less inclined than before to blurt out a declaration of his origins, and risk rupturing this tenuous relationship.

  Saf said, "You don't look very healthy, but you move as fast as I do with very little effort. I can't even see your heartbeat."

  "I'm much healthier than I look," Rakesh agreed.

  "What work do you do?"

  "I have no team. I'm looking for a new one."

  "I see." Saf fell silent. Rakesh was beginning to wonder if it was a bad thing to admit to being unemployed; he had never actually seen an Arkdweller ejected from a team, and it would be understandable if that lowered his chances as a potential recruit. If he wanted to be headhunted, he should have claimed some high-status occupation that would have had everyone trying to poach him.

  "My colleague was recruited by susk herders on the way down," Saf confided. "If you want to pull the cart with me, we can be team-mates."

  Rakesh emitted a whoop of delight from his real mouth, then calmly and politely accepted the offer. Saf stopped and showed him how to take the cart's second harness, then they continued together.

  18

  "Seventy-two more shifts and we'll be done!" Bard said proudly.

  Roi stared down the length of the giant tunnel. It vanished into the distance, the far end lost in the glow from the walls. She could hear the din of workers chipping away at the rock face, but she couldn't see them, and it probably would have taken her half a shift to reach them. There might have been other tunnels in the Splinter as long as this, but there were none as wide, or as straight. In a way, she found the sight of it stranger than anything she'd seen in the void; you expected to be shocked when you climbed outside the world, but in this ordinary place the simple rearrangement of rock and empty space had created something unprecedented: a structure with the power to move the Splinter itself.

  "Just seventy-two? Are you sure?" They were standing in the middle of the tunnel's longest segment, but there were a dozen others still growing out from their starting points, reaching toward each other but yet to join up.

  Bard retreated slightly. "Something close to that. I can't say exactly. The team's been growing steadily ever since the Jolt, but if the numbers level off we might take longer to complete it. We have as many workers as we can fit at the rock face, but we can always do with more shifting rubble."

  Word of Bard's project had spread throughout the Splinter. In ordinary times that would have counted for nothing, but it seemed that everyone who had been shaken free of their loyalties had come to take a look at the tunnel, and to hear the arguments its builders had to offer. Roi had encountered more than a dozen such travelers on her journey into the sardside, and they had all been willing to listen carefully to the case she'd made on Bard's behalf. People who, she was sure, would once have turned away in boredom and incomprehension at such useless metaphysical talk had striven patiently to come to terms with the subtleties of weight and motion, the nature of the Jolt, and the way the wind's free passage through this sardside tunnel might unbalance the Splinter and allow the garmside wind to carry them to safety.

  Bard wasn't even sure of the number of workers he had at any moment; he'd appointed supervisors to take charge of the various stretches of the tunnel, all the way from the rarb edge to the sharq, and they recruited new arrivals for themselves. When a segment was completed earlier than expected, as sometimes happened because the rock turned out to be softer than usual, the workers moved along until they found another place where they were needed.

  Roi had come to break the news to Bard that the tunnel was going to require some modifications. With the Wanderer orbiting further out from the Hub, they couldn't simply open the tunnel to the wind and then trust in their luck to carry the Splinter to safety. They would need to be able to block and reopen the tunnel at will, providing some control over the Splinter's outward spiral.

  Bard listened carefully as Roi explained what she and Ruz had observed. She knew he had lost interest in the fine points of space-time geometry, and he had nothing to say about the strange appearance of the void, but the prospect of a more complex role for his cherished creation seemed to delight him.

  "We can build cross-tunnels with plugs we can roll across into the main shaft," he suggested. "There are plenty of lodes of dense rock that we had to move whole, because they were too hard to break. In fact, if we build a whole system of movable plugs with different kinds of rock, we ought to be able to set the flow to any level you like."

  "That's a good start," Roi said. "I was wondering, though, what would happen if we needed to block or unblock the tunnel while we were in the Incandescence?"

  Bard was startled. "You think we might need such fine control that we can't wait for the next dark phase? Isn't it going to take a shift or two just to get word here that the tunnel should be blocked?"

  "I don't know what we're going to need," Roi admitted. "We still don't know how we're going to do this: what path we'll require the Splinter to take, and how we can ensure that we follow it precisely. But even if we don't need to alter the tunnel at short notice, there's a chance that as we move out from the Hub we might lose the oscillation the Jolt gave us; we might sink back into the Incandescence permanently. So we need to be able to open and close the tunnel, whether we're in the Incandescence or the void."

  Bard pondered this new challenge. "We could build some kind of system of ropes. Mount the plugs
on wheeled carts, and have people in the side-tunnels — sheltered behind fixed, dense lodes themselves — who can operate the ropes and slide the plugs into place."

  "That sounds perfect."

  Bard pressed himself against the rock, a posture jokingly suggesting that she was putting him under stress. "I hope you theorists know what you're doing."

  "I can assure you that we don't. The geometry is still beyond us. All I learned in the void was that our best guess so far is certainly wrong."

  "That's comforting." Bard looked down the tunnel and rasped frustration. "So when this magnificent work is finished, you'll want us to keep it plugged up for another thirty-six shifts while you do your calculations?"

  "At least," Roi agreed. "Maybe longer."

  "So what are we honest workers supposed to do while we're waiting for you to judge the shape of space-time?"

  Roi said, "You had plans for a second tunnel, didn't you?"

  Bard replied wryly, "On skin, a second tunnel costs nothing. It was on the drawing I made, when I first had the idea. But I spent so long failing to get the first one started that I gave up thinking about anything so ambitious."

  "You should build the second one if you can," Roi said. "Then a third, then a fourth. There's every chance we're going to need them. When we go ducking and weaving around the Wanderer, the faster we can move, the better."

  Roi's second task on the sardside was to visit Neth, and see if she could persuade her to return to the Null Chamber. The theorists would need all the help they could get, and the battle Neth had come here to fight, to win people over to the cause of the tunnel, had been resoundingly won.

  Bard had given her directions to the place where she could find Neth, but nobody could keep track of all the obstructions and detours surrounding the Great Project. The signage teams had probably all gone mad, or disbanded. As Roi passed among a group of workers shifting rubble from the tunnel's construction, she recognized one of them as Jos, the light-maker she'd met when she was traveling with Ruz and Zak.

  Jos was happy to see her, but didn't want to stop working, so Roi walked beside her, helping her to carry a heavy piece of stone. Ideally, everyone doing this job would have had wheeled carts for their loads, but there probably weren't that many carts in the whole of the Splinter.

  "This must be hard work," Roi said. "Shift after shift." She was struggling beneath the weight of the stone, even with two of them sharing the burden.

  "It's not so bad," Jos said. "We're always taking the rubble downhill, sard of the tunnel. Bard told us that every rock we move shifts the Calm a small way sardwards, strengthening the garmside winds."

  The darkness descended, but Jos insisted that they keep moving. "I've traveled this route so many times that I know it by touch."

  Roi had little choice but to trust her. "What happened to your light machine?"

  "It's at one of the rock faces. It's more useful there, where they can leave it in one place for a while. If I tried to carry it with me everywhere, I'd have no room on my back, and no strength for any rock."

  "Fair enough." Roi hadn't brought the one that Cot had given her, even though she had little else to carry; this deep into the sardside the weight would have been too much.

  "I still think about light all the time," Jos said. "What it is, how we can make it and use it." She added, almost apologetically, "There's nothing else to think about when you're carrying rocks."

  Roi was no longer surprised by statements like this. Once, it had gone without saying that work and companionship, loyalty and cooperation, were more than enough to fill anyone's mind. Now the strange urges that had made people like her and Zak such aberrations were infesting half the Splinter. The strangest thing of all was that it had not brought anarchy and chaos, famine and death. People still carried out their work, still made sure that every necessary thing was done. There was a restlessness, though, a fluidity, reshaping the organization of the Splinter, faster than any tunnel builders could reshape its rock.

  "What kind of ways could we use light?" Roi asked her. "Apart from the obvious."

  "Imagine a flat sheet of metal at one end of a tunnel," Jos said. "An ordinary tunnel, not the one we're building. You could see it clearly from a very long distance: until the bend in the tunnel took it out of sight. Now if someone turned it edgeways to you, you'd notice straight away. In the dark phase you'd need a light machine beside it, but with care you could keep it visible all the time."

  "I don't doubt that, but what use would it be?"

  "Suppose you needed to get a message to someone on the other side of the Splinter. If we had a team of people positioned in the right locations, watching for changes in each other's sheets of metal, they could pass the message faster than anyone could run. Like couriers for words."

  Roi was bemused. "Words need drumming or writing. Where are the words?"

  "We agree on a list of simple words," Jos said. "Then we divide the list in half, in half again, and so on, until the last half is a single word. Tilting the metal once can tell us which half of the list the word is in, twice which half of that half-list, and so on."

  The light was returning. Roi said, "You've thought about this for a while?"

  "It passes the time."

  If they needed to change the plugs in Bard's tunnel quickly, a system such as this might help. Roi had been struggling to imagine how they were going to navigate their way safely out to the Wanderer's orbit and beyond, when the one place where they could see into the void and the one place from which they could change the Splinter's motion were so far apart. She'd thought of trying to construct a platform for observations closer to the tunnel, but the directions of the weight made that a daunting prospect. Having to cling upside-down to the Splinter's exterior — when there was nowhere to land if you should fall — was not a situation likely to be conducive to accurate measurements.

  Roi explained all of this to Jos.

  "So you think it could actually be useful?"

  "Absolutely! You need to start work on this immediately," Roi said. "See if you can persuade some of your team-mates to join you. Work out the details, smooth out the problems. Then come and meet me at the Null Line and let me know how things are going." Roi gave her directions to the Null Chamber.

  Jos seemed overwhelmed by the sudden turn of events. "I believe you when you say this is important," she said. "But my job here, with the rocks. I came here, I listened to Bard. " She trailed off, confused. The Jolt had changed her enough to bring her here, and enough to make her restless with ideas, but she hadn't entirely lost the sense that the best thing to do was to stick with your team as long as you could.

  "When will it end?" she implored Roi. "I want the old way back."

  "You'll get it back," Roi said. "But first you have to do this."

  Jos signaled to her to halt, and they came to a stop together. With a rasp of reluctant acquiescence she eased the rock down between them.

  Roi said, "You're just going to leave that here?"

  "It's not my job any more," she replied.

  Roi found Neth alone in a chamber, surrounded by template frames. Neth greeted her warmly, and listened to all the news.

  "I'm sad to hear of Zak's death," Neth said, "but I expected it long ago."

  Roi didn't want to dwell on that. "So how are you spending your time here?"

  "I'm trying to understand the wind," Neth said. "Even before we've cut open the mouth of the tunnel, moving all this rock has changed the flow. This whole thing is not as simple as Bard suggests."

  "What do you mean?"

  "If the Splinter simply wasn't here, the wind would blow straight from rarb to sharq; we can all agree on that. I'm not convinced, though, that cutting a long tunnel through the Splinter will necessarily have the same effect. The surrounding rock will still be diverting and complicating the flow of the rest of the wind. It will all mix together in the tunnel. The result isn't easy to predict."

  Roi was dismayed. She had thought the hard p
art would be persuading people to help build the tunnel; now Neth was suggesting that it might not even work.

  "What can we do if the flow isn't strong enough to make a difference? Build more tunnels?"

  "That could help," Neth said. "But the important thing will be learning how to shape and control the flow through however many tunnels we have. What you say Bard has planned, with the varying plugs, will make a good start, but we'll need to study the effects of that arrangement, experiment with it, fine-tune it."

  "And make calculations?"

  "Of course."

  Roi struggled to reconcile herself to this new setback. She couldn't be sure that Neth was right, but she appeared to have thought about the problems of the flow more deeply than anyone else. Bard would certainly get the rock shifted and the machinery in place, but without Neth's aid, there was a chance it would all be in vain.

  She could not ask Neth to leave and join her in the Null Chamber.

  "Tell me," Roi said, "given what I saw in the void, how do you think we should approach the calculations now?"

  For a few long heartbeats Roi was afraid that Neth was going to modestly demur that it was not her place to offer advice on the matter, now that she'd left the theorists' group. Not my job any more.

  If that was her inclination, she managed to overcome it. "Try to hold on to as much symmetry as you can," she suggested. "You've shown that there isn't perfect symmetry around the Hub in all directions. But for all the time we sat in the plane of the Incandescence, nothing in the weights changed while the Splinter completed each orbit. In fact, the period of the orbit was impossible to discern without looking outside the Splinter. That tells us that the geometry as we moved around the Hub was completely unvarying."

  "We were moving through just one plane, though," Roi said.

  "Yes," Neth replied, "but the simplest way such a symmetry could arise would be if it held true for all planes parallel to the Incandescence. So if you rotate the whole geometry around an axis passing through the Hub, perpendicular to the plane of the Incandescence, it should be left unchanged. Instead of the symmetry of a sphere, look for the symmetry of an ellipsoid."