Schild’s Ladder

spacious, bed. Behind a partition, there was a shower, toilet and basin.

He sprinted after Yann, who started fleeing halfheartedly, then gave up and doubled over with laughter.

“Bastard!” Tchicaya caught up with him, and thumped him on the arm, hard enough to elicit a satisfying yelp.

“Show some cultural sensitivity!” Yann pleaded. “Pain isn’t part of my traditional gestalt.” Which made it unlikely that he’d actually felt any; even among the embodied, it was a shade conservative to let anything short of structural damage register as genuine discomfort.

“Nor is space, apparently.”

Yann shook his head, and tried to appear earnest. “On the contrary. I’ve always had a sophisticated self- and-environment map; us ex-acorporeals just aren’t hung up about its correlations with the physical world. Whatever it looks like to you, what we experience in that crowded cabin is ten orders of magnitude beyond any luxury you’ve ever known.” He said this without a trace of gloating or pomposity. It wasn’t hyperbole, or wishful thinking; it was simply true.

“You know I almost turned around and left the ship?”

Yann snickered, completely unconvinced.

Tchicaya was at a loss for any suitable parting threat, so he just raised his arms in resignation and walked back to his cabin.

Sweeping his gaze around the modest few square meters made him beam like an idiot. It was one- thousandth the size of the house he’d lived in on Pachner, but it was everything he needed.

“Bastard.” He lay down on the bed and thought about revenge.

Chapter 5

The shuttle separated from the Rindler, sending Tchicaya’s stomach into free fall. He watched the docking module retreat, knowing full well that he’d been flung off at a tangent, backward, but so viscerally convinced that he’d fallen straight down that the sight of the module?—?continuing along its arc of rotation, yet dropping from the zenith in front of him rather than disappearing behind his head?—?scrambled his sense of balance and direction completely. At first he felt as if he was tumbling backward, which would at least have explained what he was seeing, but when his inner ears failed to confirm the motion, the illusion vanished?—?only to return a moment later, to take him through the same cycle again. The lurching fits and starts that followed might have made him less queasy if they’d actually been happening; it was the inability to make sense of his perceptions that was disturbing, far more than any direct, physical effect of the lack of gravity.

He began to get his bearings once the whole ship was visible, edge-on. A minute later it had shrunk to a sparse necklace of glass beads, and the newly fixed stars finally crystallized in his mind as cues worth taking seriously. The infinite plane of whiteness on his right might have been a moonlit desert seen through half-closed eyes. He’d once flown a glider high over sand dunes at night, on Peldan, nearly free-falling at times in the thin air. There’d been no moonlight, of course, but the stars had been almost as bright as these.

Yann, sitting beside him, caught his eye. “You okay?”

Tchicaya nodded. “In the scapes you grew up in,” he asked, “was there a vertical?”

“In what sense?”

“I know you said once that you didn’t feel gravity…but was everything laid out and connected like it is on land? Or was it all isotropically three-dimensional?—?like a zero-gee space habitat, where everything can connect in any direction?”

Yann replied affably, “My earliest memories are of CP4?—?that’s a Kahler manifold that looks locally like a vector space with four complex dimensions, though the global topology’s quite different. But I didn’t really grow up there; I was moved around a lot when I was young, to keep my perceptions flexible. I only used to spend time in anything remotely like this'?—?he motioned at the surrounding, more-or-less-Euclidean space?—?'for certain special kinds of physics problems. And even most Newtonian mechanics is easier to grasp in a symplectic manifold; having a separate, visible coordinate for the position and momentum of every degree of freedom makes things much clearer than when you cram everything together in a single, three-dimensional space.”

So much for being a seasoned traveler. Tchicaya didn’t envy Yann’s upbringing, but it probably rendered the world behind the border less exotic to him than the notion of a jungle had been to Tchicaya as a child. It shook his confidence to be reminded that there were measures by which his millennia of experience had been laughably narrow.

He couldn’t have it both ways, though: he couldn’t claim that the embodied needed the shock and the strangeness of this burgeoning universe, and then wish it could be no more daunting to confront than one more mundane planetary surface.

Kadir turned around and interjected testily, “I can analyze the flows in a symplectic manifold perfectly well without pretending to inhabit it. That’s what mathematics is for. Imagining that you need to float through every last abstract space that shows up in a physics problem is just being literal-minded.”

Yann smiled, unoffended. “I’m not going to argue with you. I haven’t come here to proselytize for acorporeality.”

Zyfete, seated in front of Tchicaya, muttered, “Why bother, if you can render embodiment just as barren?”

Tchicaya bit his tongue. He’d been forewarned about the level of acrimony, and at some point everyone on the Rindler was going to have to wade waist-deep through their opponents' venom on their way to a resolution, but spur-of-the-moment bickering in a confined space wasn’t his idea of productive disharmony.

The shuttle’s drive kicked in, delivering a mild push that Tchicaya succeeded in interpreting as a precipitous dive, rather than a complete inversion of land and sky. He scanned the eye-watering whiteness, hunting for their destination, but the glare was impenetrable. It seemed miraculous to be skimming kilometers above an object that dominated the sky for hundreds of light-years?—?without being burnt to a cinder, as he would have been this close to the surface of a star?—?but it was sheer size that made the border visible from afar. Each square kilometer didn’t have to blaze fiercely for the total luminosity to outshine any supernova. Without the usual Doppler shift to boost the light’s power, a pinhole view looking straight at the border would actually have been dimmer, here, by a factor of three, than the equivalent view from any planet he’d visited. What dazzled was the fact that it filled his vision, leaving room for nothing else. On Pachner, for much of the year the border had been partly hidden by daylight, but even when it reached its furthest angle from the sun there’d always been a narrow strip of washed-out darkness left over somewhere on the horizon, with a few pallid stars on which to rest your eyes.

As the drive reversed, he finally spotted the silhouette of the Scribe. He made a mask against the surrounding glare with his hands, and managed to discern some structure. At the top of the machine was a sphere, rainbow iridescent in the light that grazed it. He knew it was embossed with a fine pattern of microjets, trillions of tiny devices capable of firing as few as one or two atoms in any direction. While the Rindler could keep pace with the border well enough simply by cruising, the Scribe’s stylus hovered so close that collisions with interstellar gas, and even the pressure of the borderlight itself, would have ruined the alignment if left uncompensated. Presumably, the visitors' own influence would be well within the machine’s defensive capacities, but to Tchicaya it was both marvelous and comical that their presence could be accommodated?—?like a calligrapher inscribing Gravitation on the head of a pin, while four fat infants clambered onto the artisan’s shoulders and proceeded to wrestle.

As the shuttle drew nearer, the Scribe’s modest size became apparent; it was smaller than one of the Rindler's modules, forty or fifty meters across, with the sphere of microjets held out on a boom above a flat deck. The shuttle’s drive made one last perceptible correction before a series of maneuvers too gentle to feel brought them into contact with the deck.

Kadir unstrapped himself, and approached the hatch in the floor of the shuttle. Tchicaya followed him.

“You keep an atmosphere in there?”

Kadir nodded. “People come and go, it’s easiest just to maintain the pressure.”

Tchicaya frowned. “I’m never going to get to use this, am I?” He pinched the back of his hand to tug on the