by Greg Egan
“The one bad thing that always happens in my dreams,” he confessed, “is that the anchors all break free of the ground and rise into the air, while the balloon drifts upward toward absolute summer.”
Amina said, “If that does happen, you’ll be famous for rewriting half a dozen laws of physics before reaching your death.”
“That’s comforting,” Seth replied. He started down the stairs, trying not to dwell on the fact that a couple of snapped ropes could deliver the same endpoint far more easily, and with none of the glory.
as night approached, seth heard the rain spreading across the steamlands, but at the work site the air remained calm. He sat on the hillside in the twilight and watched the balloon floating beside the furnace room like a giant, inverted piece of fruit, its skin rippling and wrinkling as it swelled and ripened from the heat. A dozen short ropes restrained it, sparing the three anchors for now.
He heard footsteps approaching from the east, then Raina called out, “We have visitors!”
When Seth saw who accompanied her, he rose to his feet. “Welcome to the edge of madness. Are your husbands with you? And the children?”
“No, but Amir and Aziz send their good wishes.” Sarah clasped Seth’s shoulder in greeting.
Judith added, “They were tempted to make the journey, but it wouldn’t have been fair on our parents to expect them to look after the children for so long.”
Theo said, “You’ve arrived just in time: one day later, and you would have missed history being made.”
“Nothing’s over in a day,” Judith replied.
«Meaning what?» Theo wondered, before asking aloud, “Have you volunteered to do follow-up measurements?”
Sarah said, “We’re here to help in any way we can.”
“It’s a long way to come without a definite plan!” Theo seemed to be doing his best to sound friendly, but he couldn’t entirely erase the suspicion from his voice. He addressed Seth in private. «Why do I get the feeling that the armchair surveyors in Baharabad have already decided what comes next?»
«Paranoia?»
«Were you asleep through all the politics and infighting when I was trying to sell them on the project?»
«Quite possibly,» Seth admitted. Some of the meetings had lasted for hours, and since Theo had done most of the talking, it had only seemed fair to let him do most of the listening as well.
Sarah said, “Whatever you find, there’s sure to be more work to be done here. But I’m glad we arrived in time to wish you luck.”
“Thank you,” Seth replied.
Theo said, “Thanks for your good wishes—but if we find what I’m expecting, the work to be done will all be elsewhere.”
Judith laughed. “You think you get to make all the rules now?”
“It’s the world that makes the rules,” Theo retorted. “Or are those cliffs just a figment of my vanity?”
“We’ll only know what they are when we’ve mapped them properly,” Judith insisted. “But even if your guess turns out to have been right, that doesn’t turn your every whim into some kind of decree.”
Seth said, “I’m not going to spend what might be my last night alive listening to two bickering Siders. If you want to keep arguing, do it in your own language.”
There was an awkward silence, then Raina spoke. “I’ll be back in a little while, and we can go through the basket checks together.”
“Of course,” Seth replied.
As Raina and Sarah walked away back up the hill, Theo said, «If you’re having second thoughts, we don’t need to do this. There are plenty of people who’d be willing to take our place.»
«Fuck off.» Seth gazed at the balloon; the upper half, into which the hottest air fresh from the furnace had risen, was taut now, the skin stretched out as far as it could go. The thought of the impending journey terrified him, but he was trapped by his own vanity, not Theo’s. «You’re the one who doesn’t need to do this,» he said. «You could crawl out for the duration and wait on the ground. This is all about light; you wouldn’t be missed.»
«I’m not worried at all,» Theo declared brashly. «Everything’s been tested a dozen times. We’ll be safer tomorrow than we ever were stumbling about near the edge of the cliffs in the rain.»
«Maybe.» To back out now would be humiliating—but Seth had decided that the worst thing would be to back out and then watch their replacements die. So the more afraid he was that the ascent might go badly, the less choice he had.
an hour before dawn, Seth climbed into the basket and moved into position, lying face-down over the observation bay. He could smell the soil an arm’s length below the aperture, but all Theo could show him were his own hands beside two slates; the sides of the basket were so high that even the edges couldn’t be pinged from here.
“Are you comfortable?” Raina asked, standing beside him.
“As much as I’ll ever be.”
“Try reaching the alidade,” she suggested.
Seth maneuvered his right hand through the access hole and groped around for the sighting bar. Once he was touching it, he picked up a pencil with his left hand and scribbled a few random figures at the top of the slate. Theo pinged the thick residue clearly enough, and the numbers appeared legible. “It’s fine,” he said. He’d practiced all of these tasks many times, but there was still something reassuring about the last-minute checks.
“All right,” Raina said. “See you soon.”
Seth listened to the squeaking of the boarding ladder as she departed. When she was gone, all he could hear was the slow wheezing of the balloon itself, like a giant in poor health standing over him, trying unsuccessfully to breathe quietly.
Theo, though, had heard something more. «Here we go!» he announced excitedly, sounding as untroubled as if they were about to sled up a ramp.
The restraint ropes were cut in rapid succession, sending the basket tipping unevenly until it was free. The balloon rose up smoothly for a second or two, then it jerked and swung westward a short distance before finding itself suddenly constrained again. Seth braced himself and waited for the motion to die down, glad that it was still too dark for him to see the ground shifting below.
Eventually the balloon settled, having found the spot where all three anchor ropes were taut. In the stillness, Seth felt his fear abating. Give or take the effects of the wind, the teams on the ground could now control his position by choosing how much rope to dispense from each reel. He trusted the rope teams, having witnessed their discipline first-hand—and if he’d marveled at the elegance of the positioning system when he’d merely been watching from the ground, here, even in the darkness, he felt the consequences more viscerally than ever. Three hyperboloids with three different centers intersected in a single point. That geometric theorem was keeping him from drifting away into the summer sky.
The unreeling began, and the balloon rose and shifted, smoothly for the most part, sometimes in fits and starts. Seth stared down through the observation bay at the dark land spread out beneath him, where the blackness was beginning to give way to hints of desert hills in the predawn light. The exact scale was difficult to judge, and for all he knew thousands of people might have enjoyed higher vantage points from various mountainsides. But if his altitude alone was as yet unexceptional, his separation from the ground was already surreal.
The balloon wanted nothing more than to ascend, but the rope teams offered it a deal: it could only gain altitude by moving south. Below, slender threads of pale gray appeared, water reflecting the brightening sky. When the strip of vegetation beside the steamlands slid into view, Seth felt a giddy thrill at the sheer speed and effortlessness of the journey. On foot, it would have taken him at least half a day to come this far—and for all their labors, the rope teams had only dispensed a tiny fraction of the horizontal distance he’d covered.
«We were right to thank the furnace workers,» he told Theo. If anyone’s exertions had been commensurate with this result, it was theirs.
/> Vegetation gave way to mud flats, still damp and glistening in places, though the dustier, desiccated regions were growing visibly larger as he watched. At the sight, Seth became conscious of the heat, which had arrived with such speed that he’d had no time to dwell on it. The sides of the basket shielded him from any possibility of direct sunlight, but his altitude alone thrust him even deeper into summer than the parched land below. Still, the temperature was not intolerable—and if a scamper could complete the journey and return unsinged, he had no reason to start fretting when his own trip had barely begun.
«Almost, almost,» Theo muttered. Seth shifted his shoulders and tried to make himself ready; he’d been lying so still that all his muscles had grown stiff.
The cliffs came into view on his right, at the periphery of his vision, but the pace of the balloon left him with no time to grow impatient; if anything, he wished it could have moved more slowly, giving him a better chance to understand what he was seeing. The mud flats disappearing to the north remained crisp and comprehensible, but past the edge, in the gloom untouched by the dawn, he could find nothing for his eyes to fix on.
The ropes were slowed and locked; the basket lurched disconcertingly, but then stabilized, swinging gently. They had come to a halt just south of the edge, leaving Seth staring down at the sheer rock of the cliff face on his left, while below, and stretching to his right as far as he could see, was a shadowed landscape so dark and distant that only the constancy of its few discernible features convinced him that they were more than hallucinations, summoned by his eyes to puncture the monotony of the blackness.
«So it’s not straight down forever,» he said numbly, as if that had ever been a real prospect. But finally glimpsing the floor—or shelf—that had stopped all the pebbles he’d tossed over the edge from actually falling all the way to the antipode was no small comfort.
«I think that gray patch in the upper right is something we can fix on,» Theo suggested, laudably businesslike in the face of the vertiginous spectacle beneath them. «Even when the background’s not as dark, it should show enough contrast.»
«Right.» Seth reached out and brought the alidade into play, then sighted the pale feature and recorded its angle from the nadir. The light remained too dim for him to see the instrument’s markings with his eyes, but the alidade was geared to a pointer on his left, which showed the angle on a dial that Theo could ping.
As the sky brightened, they chose another dozen points to record. Seth could only guess what kind of geology these distant smudges of contrast represented, but so long as they hadn’t been fooled by pools of water that might shift or vanish, it didn’t matter exactly what they were seeing.
«Notice anything to the south-west?» Theo asked.
Seth regarded the unmitigated blackness. «No.»
«Exactly. If this were flat ground, then the shadow of the cliffs would come to an end. Dawn would be breaking.»
«I’m not sure we could see that far.»
«If the ground slopes down, it will be even farther. And if the slope is steep enough, it might not happen at all.»
«Let’s wait for the data,» Seth urged him.
«The absence of dawn isn’t data?»
«It says something, but it’s not quantitative yet.»
Theo laughed, undiscouraged. «All right, have it your way.»
The teams on the ground set to work again, reeling the balloon in to the west while dispensing more rope from the eastern anchor point. With the sun climbing higher, the scattered light was bringing out more details in the terrain below: forked gray streaks that might have been rivers, and sharp edges that might have marked further cliffs beyond the initial drop. Seth did his best to sketch the main features on the slate to his right, though drawing at this strange angle was even more difficult than scrawling numbers. A heavy mist—or perhaps a bank of clouds—drifted in from the south, and for a while he was afraid that it might obscure his sighting points, but it thinned and broke apart before it reached them.
When the balloon halted, Seth waited for it to stabilize, then he quickly repeated the measurements. He had no intention of trying to interpret these numbers before he was back on the ground, but his Sider had no qualms about trusting his own mental arithmetic.
«There’s a clear slope down to the south,» Theo declared. «Almost forty-five degrees.»
Seth had expected a significant gradient, to explain the runoff battering the cliff face that Amina had taken for a storm. But forty-five degrees was not an angle much seen in geology. Any slab of rock that was initially horizontal was likely to encounter serious obstacles long before it was sloping more than ten or fifteen degrees north-to-south.
«Isn’t that what I predicted?» Theo demanded gleefully. «Go deep enough, and the pressure from all the rock overhead can’t be held in along a vertical face; there’s nothing pushing back from the south. Eventually, the rock has to bulge out, spreading the change in pressure over a greater distance the deeper you go.»
«So it’s some kind of hernia,» Seth conceded. Nothing had tilted to create the slope; it was a by-product of increasing amounts of horizontal slippage. «But we still don’t know the size of the cavity into which the world’s straining bowels have protruded.»
«You put it so poetically. You know my answer, though: there is no cavity. To the south of this, there’s only air, and then the void.»
The heat was becoming harder to ignore. Seth pressed his foot against the lever that operated the cooling system, opening a grate that allowed droplets of water to fall onto his back. He kept the lever engaged for half a minute, then shut off the grate; the water gave him some relief, but the supply was limited.
The ropes were adjusted again, hauling the balloon even farther to the west. Seth could see rain falling now, from a patch of clouds that passed almost directly below. He watched the glistening runoff flowing uphill to the north, spilling rapidly across the dark rock, but before it reached the cliffs it struck a change of gradient that brought it to a halt. At one degree less than forty-five, water would rush up a slope, but at one degree more it could only move downhill. The illusory storm must have arisen from a long stretch of terrain where the slope had remained below the critical value all the way to the bottom of the cliffs.
Seth started the third set of measurements, still relying on Theo to ping the angles; the dial directly in front of him was no longer in darkness, but there was a glare behind it to which his eyes were forced to adjust, rendering the instrument illegibly dim in comparison. The distracting brightness did not seem to emanate from the land; there was still no sign of dawn breaking anywhere south of the cliffs, and he had already moved a screen into place to spare himself the sight of the sun-baked mud flats to the north. Eventually he understood that the glare could only have one source: the air below him, between the balloon and the boundary of the cliffs’ shadow. The sunlight was so intense that even the tiny fraction being scattered his way was enough to dazzle him.
Theo recalculated the positions of the landmarks, and announced that his earlier conclusions remained unchallenged. «There’ll be no crossing this, or skirting around it,» he said. «We need to halt the sun, or we’re finished.»
«No one’s going to accept that from one set of observations,» Seth cautioned him.
«Of course not,» Theo replied. «Let them do a dozen follow-ups if they want to. But do you honestly think they’re going to find anything that will change the outcome?»
Seth had no energy to pursue the argument; all he could think about now was the heat. He slid the screen across the observation bay, blocking it completely, and sprayed his back with water again. «Reel us in,» he begged, as if the rope crews could read his mind and depart from their schedule. In the trials, he’d taken care not to rush his pretend measurements, to be sure that he’d have plenty of time to complete the real ones if anything went awry.
After a few minutes they began to move again, but Seth’s relief was short-lived: even with the obser
vation bay closed, he could tell from the way his body pressed against the floor that the balloon was ascending, rising up and heading south. Seconds later it halted abruptly, leaving the basket swinging. «What the fuck are they doing?» The churning in his gut went far beyond any physical effect of the ropes’ unreeling. If the balloon could travel in entirely the wrong direction, then all his trust had been misplaced, all his confidence sheer naïveté.
Theo replied tentatively, «They might have stripped a ratchet. That brake was slammed hard: I heard the rope twang.»
Seth doused himself with water to clear his head. «That’s possible.» The combined strength of each rope team was enough to counter the buoyancy of the balloon and reel it in, but it was the ratchet that kept them from surrendering their hard-won gains between bouts of exertion. Dragging on the rope then slamming down the brakes each time it began reversing wouldn’t just be slow and inefficient: each sudden rise in tension risked damaging the rope—either severing it completely, or snapping the fibers that prevented axial buckling.
«How long do you think it would take them to replace it?» Theo asked.
«Half an hour. Maybe longer.»
Theo was silent. So far, he hadn’t complained about the heat, but that didn’t mean he wasn’t feeling it.
«The real problem’s the amount of tension,» Seth reasoned. «If we could lower that, they might be able to get us down without the ratchet.»
«You mean reduce the buoyancy?»
«Yes.» In the earliest tests, they’d aimed to have the air in the balloon cool quickly enough to facilitate its own descent, but that had left too fine a line between a successful ascent and a dangerous lack of buoyancy when it was needed. «We should have put a valve on top.» The consensus had been that that was dangerous, too, in case the control lines snagged and it opened prematurely.
Theo said, «But in the absence of a valve . . .?»
Seth rose to his knees and looked around the basket. There was a box of spare pencils and slates, three canteens of water, and a bag of bechelnuts. He glanced up at the underside of the balloon, squinting against the glare. The fabric of the panels was a tough triple-weave; a pencil wasn’t going to pierce it.
