A chorus of weary denials came back at her; they were tired of being asked. She’d been pacing the tour carefully—and the mountain’s interior was maintained at higher pressure than the air outside—but everyone’s metabolism was different, and Yalda had decided that it was better to nag than face a crisis. She certainly didn’t want any of these potential recruits associating the place with sickness.
“All right, we’re now coming to one of the top engine feeds.” For the last few saunters the tunnel had been lit solely by the red moss clinging to its walls, but the illumination from a more variegated garden could already be seen spilling around the bend.
As they took the turn, a vast, vaulted chamber appeared in front of them, a disk almost half a stroll wide and a couple of stretches high. It had been hollowed out of the rock three years before, using jackhammers powered by compressed air; no engines or lamps were employed in the presence of naked sunstone. The usual drab moss and some hardy yellow-blossomed vines covered the arched ceiling, but between the supports the floor was a maze of flower beds luminescing in every hue. Many of the plants were arranged haphazardly, or in small, localized designs, but long strands of cerulean and jade could be seen weaving from garden to garden around the gaping black mouths of the boreholes.
“It wasn’t always so colorful here,” Yalda recalled, “but the construction workers brought in different plants over the years.”
“Will you keep the gardens when the engine’s in use?” Nino asked.
“No—that would interfere with the machinery, and in the long term their roots could even damage the cladding. But these plants won’t be destroyed; they’ll be shifted to the permanent gardens higher up.”
Yalda led her dozen charges to the edge of the nearest borehole and invited them to peer down into the gloom. Far below the chamber, the darkness was relieved by four splotches of green and yellow light; clinging to rope ladders that ran the full height of the shaft, workers wreathed in vines were inspecting the hardstone cladding that lined the surrounding sunstone.
“When the engine is operating,” Yalda explained, “these holes will have been filled-in again, but liberator will be pouring down around the edges. If there are gaps in the cladding, the fuel could start burning in the wrong place.”
“This is the top layer of the rocket, isn’t it?” Doroteo asked.
“Yes.”
“So it won’t be in use for a very long time,” he pointed out.
“That’s true, and I’m sure it will be inspected again before it’s fired,” Yalda said. “But that’s no reason for us to neglect the job now.” Her ideal would have been to prepare every piece of machinery in the Peerless in such a way that the travelers would be able to turn around and come home safely whenever they wished—without requiring any new construction work, let alone any radical innovations. But given the current yield from the sunstone, this top layer of fuel would actually be burned away sometime during the decelerate-and-reverse phase, halfway through the journey. Relying on the status quo would not be an option.
Yalda led the group to a stairwell at the rim of the chamber, and they gazed up into its moss-lit heights. Four taut rope ladders ran down the center—installed early in the construction phase and retained in anticipation of weightlessness—but for now a more convenient mode of ascent involved the helical groove three strides deep that had been carved into the wall, its bottom surface tiered to form a spiral staircase.
“We’ll be climbing up four saunters here,” Yalda warned the group, “so please, take it carefully, and rest whenever you need to.”
Fatima said, “I don’t feel weak, but I’m getting hungry.”
“We’ll have lunch soon,” Yalda promised. Fatima was a solo, barely nine years old; Yalda felt anxious every time she looked at the girl. What kind of father would have let her travel alone across the wilderness, to enlist in a one-way trip into the void? But perhaps she’d lied to him in order to come here; perhaps he thought she was hunting for a co-stead in Zeugma.
The group was evenly split between couples and singles; the singles were all women, except for Nino. Yalda hadn’t interrogated Nino about his background, but she’d formed a hunch that he was that rare and shameful thing, a male runaway.
They began trudging slowly up the stairs; the pitch appeared to have been set to discourage running, should anyone have felt tempted. Their footsteps, and the whispered jokes of Assunta and Assunto up ahead, came back at them in multiple echoes from the underside of the stairs above. Beyond their own presence, Yalda could hear an assortment of odd percussive sounds, creaks and murmurs drifting down from higher levels. The workforce inside the mountain had fallen far below its peak, but it still numbered about a dozen gross, and most of the activity now was in the habitation high above the engines.
“Will the travelers be able to see the stars?” Fatima asked Yalda, trailing her by a couple of steps.
“Of course!” Yalda assured her, trying to dispel any notion that the Peerless would end up feeling like a flying dungeon. “There are observation chambers, with clearstone windows—and it will even be possible to go outside for short periods.”
“To stand in the void?” Fatima sounded skeptical, as if this were as fanciful as walking on the sun.
Yalda said, “I’ve been in a hypobaric chamber, as close to zero pressure as the pumps could produce. It feels a bit… tingly, but it’s not painful, and it’s not harmful if you don’t do it for too long.”
“Hmm.” Fatima was begrudgingly impressed. “And in the sky—will they be our stars, or the other stars?”
“That depends on the stage of the journey. Sometimes both will be visible. But I’ll talk about that with everyone later.” A moss-lit staircase wasn’t the place to start displaying four-space diagrams.
They emerged from the stairwell into a wide horizontal tunnel; this one ran all the way around the mountain, but the nearest junction was just a short walk ahead. Yalda offered no warning as to what lay around the corner; the light gave some clues, but the thing itself always took the uninitiated by surprise.
The chamber was no wider than the one below, but it was six times taller—and the broad stone columns supporting the arched ceiling were all but lost among the trees. High above their heads, but far below the treetops, giant violet flowers draped across a network of vines formed a fragmented canopy that divided the forest vertically. With no sunlight to guide their activity, these flowers had organized themselves into two populations with staggered diurnal rhythms, one group opening while the others were closed. Through the gaps left by the sagging, dormant blossoms, shafts of muted violet reflected back by the stone above revealed swirling dust and swooping insect throngs. Even the air moved differently here, driven by complex temperature gradients arising within the vegetation.
Yalda strode forward through the bushes that had been planted around the chamber’s edge, where the ceiling was too low for trees. “This might look like a strange indulgence,” she admitted. “When we have farms, plantations and medicinal gardens, what need is there for wilderness? But if our survival depends on the handful of plants we’ve learned to harvest routinely, this place still encodes more knowledge about light and chemistry than all the books ever written. Every living organism has solved problems concerning the stability of matter and the manipulation of energy that we’re only just beginning to grasp. So I believe it’s prudent to bring as many different kinds of plant and animal life with us as we can.”
“What kind of animals?” Leonia asked; she didn’t sound too happy about the prospect of sharing the Peerless with a teeming menagerie.
“In here right now, there are insects, lizards, voles and shrews. Soon we’ll be adding a few arborines.” Yalda watched the group’s reaction with her rear gaze; eventually it was Ernesto who said, “Aren’t arborines dangerous?”
“Only when threatened,” Yalda declared confidently. “Most of the stories about them are exaggerated. In any case, they’re our closest cousins; if th
ere are medical treatments we need to test, there’s only so much you can learn from a vole.” It was Daria who’d sold her on most of these assertions—the same Daria who’d made half her wealth from impresarios’ claims about the creature’s ferocity.
Fatima said, “What happens when there’s no gravity? Won’t everything… come loose?”
Yalda squatted down and cleared a small patch of soil, exposing the layer of netting that sat over it. “This is attached to the rock with spurs at regular intervals. The root systems bind the soil together, too—and the soil itself is actually quite sticky. A handful of soil will trickle through your fingers easily enough, but an absence of gravity is not the same as turning everything upside down. What I’m expecting is that the air here and in the farms will grow hazy with dust, but there’ll be an equilibrium where that dust is re-adhering to the bulk of the soil as often as it’s breaking free.”
They took the stairs up to one of the farms, and ate a lunch prepared from the local crops. Wheat adapted well to sunlessness; it grew faster in here than on the farms outside, now that Gemma had all but banished night again. The disruption caused by the second sun varied with the season and the year—and there were periods when it rose and set close to the original, almost restoring normality—but the last Yalda had heard from Lucio was that he and her cousins had given up trying to adjust to the complicated cycle and were simply building canopies over all their fields.
Then it was on to the storerooms, workshops and factories, the school, the meeting hall, the apartments. They ended the day in an observation chamber close to the peak, where they watched the sun setting over the plain below, revealing the mountain’s stark shadow in the rival light from the east.
There was a food hall beside the chamber. Yalda found a free patch of floor among the crowd of construction workers and sat everyone down. Up here they were far enough from the sunstone to use lamps; it might have been any busy establishment in Zeugma or Red Towers.
Yalda dropped her recruiting spiel and let the group eat, with no accompaniment but the sputter of firestone and the chatter of their fellow diners. By now they’d seen not the whole of the Peerless, but at least one example of everything it contained. They’d reached the point of being able to imagine what it would be like to spend their lives inside this mountain.
Leonia, who’d been tense throughout the tour, now appeared almost tranquil; Yalda’s guess was that she’d made up her mind to find an easier way of avoiding her co than fleeing into the void in the company of wild animals. Nino looked haunted, but equally resolved to make the opposite choice. Looking back, Yalda realized that every question he’d asked her had concerned something innocuous or trivial; it was as if he’d wanted to appear engaged as a matter of courtesy, but he’d been so committed to his plan from the start that he’d preferred not to delve into anything that might risk swaying him.
With the others, she was unsure. It was as easy to undersell the problems the travelers would face as to oversell them. Anyone who reached the end of the tour believing that the project was hopelessly ill-conceived would walk away—but equally, anyone who was convinced that the triumphant return of the Peerless was inevitable would have scant motivation to join the crew. Rather than sentencing your descendants to indefinite exile, why not choose the version of events that lasted a mere four years, in which your death far from home was replaced by the imminent arrival of the most powerful allies you could hope for? Of course a Hurtler might incinerate the world before then, but it had been five years since Gemma’s ignition, so it wasn’t hard to imagine the same luck holding out for another five.
In between those two extremes was a sweet spot, where the mission’s potential was beyond doubt but its success remained far from guaranteed—allowing a wavering recruit to imagine their own contribution tipping the balance. Yalda aimed squarely for that result, and she no longer felt guilty or manipulative for doing so. The truth was, though she and Eusebio had filled all the jobs that they knew beyond doubt to be essential, there was nothing gratuitous about raising the numbers still higher—increasing the range of skills, temperaments and backgrounds among the travelers. It was like bringing the forest as well as the farms: the Peerless was sure to find a use for everyone, even if they could not yet say what it would be.
“One came back!” Benedetta shouted ecstatically, running across the sandy ground between the main office and the truck compound. There was a rolled-up sheet of paper in her hand. “Yalda! One came back!”
Yalda gestured to the group to wait for her. She’d been about to take them over to the test site to watch a demonstration launch, but if she understood Benedetta’s cryptic exclamation then this was worth a delay.
Yalda jogged over to meet her. “One of the probes returned?”
“Yes!”
“You’re serious?”
“Of course I’m serious! This is the image it took!”
Benedetta unrolled the crumpled sheet.
Yalda had barely taken in the spatter of black specks when Benedetta turned the paper over to show her the opposite side. It had been marked with three signatures in red dye: Benedetta’s, Amando’s and Yalda’s, along with a serial number, an arrow in one corner to fix its orientation in the imaging device… and instructions to anyone finding it upon its return.
Apart from the image on the sensitized side, Yalda certainly recognized the sheet. It was one of a gross that she’d signed at Benedetta’s request, two and a half years earlier, to guarantee their authenticity.
“Who sent this to you?”
“A man in a little village near Mount Respite,” Benedetta said. “I’ll need your authorization to pay him the reward.”
“Do you know what state the probe itself is in?”
“In his letter he said there wasn’t much left of it apart from a few cogs hanging off the frame, but it was still so heavy that he couldn’t afford to send it to us.”
“Add something to the reward to cover the freight, and get us the whole thing.” Yalda took the sheet from her. “Octofurcate me sideways,” she muttered. “You and Amando really did it.” She looked up. “Have you told him yet?”
“He’s in Zeugma helping Eusebio with something.”
“I never thought this would work,” Yalda admitted.
Benedetta chirped gleefully. “I know! That makes it so much better!”
Yalda was still having trouble believing it. She was holding in her hands a sheet of paper that had left the world behind, crossed the void faster than anything but a Hurtler, turned around and come back… and then traveled here by post from Mount Respite.
“Which stage was it taken in?” she asked.
Benedetta pointed to the serial number.
“Meaning…?” Yalda had forgotten what the numbers signified.
“Odd numbers were for the first stage of the journey, when the probe was traveling away from us.”
“Good,” Yalda managed numbly. She thought for a while. “I think you should come and tell my recruits what you’ve found.”
“Of course.”
Yalda introduced Benedetta to the group, then recounted some of the background to the problem. Years before, she had managed to identify a slight asymmetry in the Hurtlers’ light trails, demonstrating that their histories were not precisely orthogonal to the world’s. This had finally made it possible to say which direction they were coming from; until then, their trails might have marked a burning pebble crossing the sky in either direction. But it had revealed nothing about the Hurtlers’ own arrow of time.
Doroteo was confused. “Why doesn’t their arrow of time just point from their origin to their destination?”
Yalda said, “Suppose you drive toward a railway crossing, and you notice that the track doesn’t make a perfect right angle with the road you’re on; it comes in from the left as you approach the crossing. You might think of the ‘origin’ of the track as being a station that lies behind you, to the left—but assuming that this track is only used in
one direction, you still have no reason to believe that the trains will actually be traveling from your left to your right.”
Doroteo grappled with the analogy. “So… we can map the geometry of a Hurtler’s history through four-space as a featureless line, but we can’t put an arrow on it. We can’t assume that the tilt you discovered means the Hurtler’s arrow is pointing slightly toward our future; it might as easily be pointing slightly toward our past.”
“Exactly,” Yalda said. “Or at least, that was how things stood until now.”
Benedetta was shy before the strangers, but with Yalda’s encouragement she took over the story.
The probes had been launched two and a half years earlier: six dozen rockets fuelled by sunstone from the mountain’s excavations, fitted with identical instruments and sent out like a swarm of migrating gnats in the hope that one of them would complete its task and find its way home. Their flight plan had been a less ambitious variation on that of the Peerless, reaching just four-fifths the speed of blue light before decelerating and reversing, with literally just a couple of bells spent in free fall along the way. Compressed air, clockwork and cams controlled the timing of the engines, with opposing pairs of thrusters built into the design to avoid the need to rotate the craft. The aim of the project had been to get an imaging device moving as rapidly as possible, parallel to the Hurtlers’ path, first in one direction and then the opposite.
“This paper was made sensitive to ultraviolet light, about one and a half times as fast as blue light,” Benedetta explained, holding up the travel-worn sheet. “The orthogonal stars all lie in our future, so we can’t expect to see them, or image them under ordinary conditions. But the whole meaning of ‘past’ and ‘future’ depends on your state of motion.”
She sketched the relevant histories on her chest.
“With the probe traveling at four-fifths the speed of blue light, infrared light from the orthogonal stars would have reached it at an angle in four-space corresponding to ultraviolet light from the past.” Benedetta held up the evidence again. “So we’ve managed to record an image of these stars—which to us still lie entirely in the future—by giving the probe a velocity that placed part of their history in its past.”