Грег Иган - Phoresis

She lay still in the wreckage for a while, afraid that if she tried to move she would discover that she couldn’t. Maybe the best thing would be to rest where she was, until the shock of the impact had passed. But what if she lost consciousness?

She rose to her feet and took a few tentative steps. One of her legs had been cut, but not deeply. She felt battered, and when she flexed her right hand she knew she’d broken a finger, but her back and her limbs were intact.

Rosalind looked up across the ice and saw the tower in front of her in the distance, glinting in the late afternoon sun. She knew where she was now, and how far she had to travel. It was going to be a long walk, but there was no chance of getting lost.

As she set off, she turned back to survey the fragments of the glider strewn over the ice. She was going to have to think of the next one as new.

“I’m convinced,” she said softly. “We can survive the crossing.” She marched toward the tower, repeating the words in her mind, hoping that she’d be able to speak them with conviction by the time she reached her friends. If she’d died, they would have had to go looking for another solution, but now there was no point believing anything else.

As she walked through the village toward her mother’s house, Rosalind couldn’t help but feel self-conscious at how well-fed she must have looked. Not everyone she passed was alarmingly emaciated, but no one was carrying any flesh in reserve. To be ashamed of the disparity would be foolish; there’d be no point sending the expedition to Tvíburi if they all starved to death waiting for their first harvest. And if the provisions and laborers the villagers had sacrificed to the tower for the last four generations had been a heavy price to pay, she wasn’t exactly taking an easy path herself. Still, she could not recall the last time she’d really been hungry, and she doubted that was true of anyone else in sight.

When she entered the house, she saw that her mother had invited her paternal aunt, Marion, to the farewell meal, along with Marion’s daughter, Celine. Rosalind embraced them all in turn, though she’d never been close to her father’s side of the family.

They sat down at the table and began to eat.

“How quickly do you think the new villages will be established?” Marion asked. When Rosalind hesitated, she made the question more specific. “Do you think you’ll be seeing Celine there?”

“I hope so.” The older women had no expectation of reaching Tvíburi themselves. Rosalind turned to Celine. “If you ever have time, there’s no harm in practicing with a glider. If you start from low jumps, it’s not dangerous.”

“Practice, and wait for the signal,” Marion said.

Rosalind nodded. “By the time our children are old enough to help us in the fields, we should have sowed enough land for the farms to be visible through any decent telescope. Though I’ll be happier still if I’m the one who looks up, to see a new geyser sprouting from the limb of Tvíbura. In which case, migrants will still be welcome… but we won’t expect quite the same influx.”

Celine laughed, but Rosalind’s mother looked horrified. Rosalind offered her a questioning frown. Would it be better if I wished an endless famine upon the world, just to make myself less lonely?

Her mother said fervently, “Tvíburi is the future. We all know that. You’re giving us a future we’d never have otherwise.”

Rosalind was embarrassed. “I’ll do my best,” she said.

Mercifully, Celine was impervious to her aunt’s solemnity. “How many stairs are there in the tower?” she asked. “From bottom to top?”

“I don’t honestly know,” Rosalind admitted. “If I tried to calculate the total now off the top of my head, I’d probably get it wrong.”

“Don’t worry,” Celine replied. “When it’s my turn, I’ll make sure to count them, and I’ll tell you next time we meet.”

The last level of the tower was the tallest, and it had no stairs at all. Rope ladders stretched between the annular rest platforms, but though the bottoms of the platforms were helpfully painted red and the top surfaces blue, Rosalind struggled to perceive any fixed direction as up or down. She felt like an insect crawling along inside a hollowed-out tree branch, which a child had picked up and was whimsically turning this way and that. It was not that she feared being dislodged, and it seemed absurd to imagine that she could ever lose her way. But as she moved, hand over hand, in near weightlessness through the tube of luminous ice, the sense of disorientation was impossible to shake off. All she could do was embrace it, and hope she wouldn’t throw up.

“Matilda told me it was beautiful up here, but I never imagined!” Joanna called out, from a dozen rungs behind her. Matilda had worked on completing the tower, when the only thing at the open end between the ice-farmers and the void had been a series of tarpaulins, which were meant to trap the air but were forever coming loose or getting torn. She’d once told Rosalind that she’d often had to spend half a day without breathing, while the tarps were repaired and air was pumped in from the level below.

Sigrid said, “I’ll reserve the word beautiful for the first sight of fertile soil between my fingers.” She glanced across at Rosalind from her adjacent ladder. “Or better yet, my first child born on that soil.”

“Yeah, yeah,” Joanna replied tetchily. “It’s all about the practicalities; the rest is just a distraction.”

“Do you think a thousand people should have died just to give you a pretty ice sculpture?” Sigrid retorted.

“No. But that doesn’t stop me appreciating every part of what they built.”

Rosalind knew better than to urge them to make peace, or even just spare her from having to listen to their nonsense. They’d never actually come to blows over these meaningless quibbles, so if they found the bickering helped them pass the time, who was she to object?

As their last day attached to their birth world wore on, the sun crept below them without actually setting, even as Tvíburi turned gibbous behind the wall of ice. Rosalind couldn’t really discern its shape, but the slowly growing illumination from the west side of the ice ahead of her was all she needed in order to picture the new dawn sweeping over the face of the twin.

For all that the rules of light and geometry rendered everything she was seeing explicable, it remained deeply unsettling. If anything, what shocked her was that these strange sights made so much sense. As a child, she’d experimented with lamps and fruit, visualizing every stage of this journey. For the real sun, and the real worlds, to recapitulate her clumsy shadow play made her feel like someone half prophet, half puppet, unable to decide if she’d shaped this future, or if it had reached back in time and shaped her.

Then again, maybe light was just light, and spheres were just spheres, and the humblest piece of fruit cast its shadow no differently than the world itself.

When the sun finally went behind Tvíbura, leaving the softer glow of their destination to light the way, Rosalind counted the number of annular platforms she could make out above her—and for the first time, it had fallen from the usual eight all the way down to six. At first, she thought she might be losing a couple to the change in the light, but as she passed the nearest of the six, nothing emerged in the distance to make up for it.