Carla’s gut tightened. She hadn’t been hungry since the journey began, but she found herself longing for the comforting aroma of groundnuts.
Other hands feeling steady? she asked Ivo.
Very, he assured her.
She wanted to see this reaction close up; the more she pondered the mystery, the more she ached to understand it. She just didn’t want to end up partaking in it herself.
Gyroscopes kept the Mite’s orientation locked against the stars, so as its orbit carried it around the Object, the Object in turn moved across the sky. Carla hardly needed to check the clock to know when they’d made half a revolution: the terrain that now stretched out above her head, its wide horizon upside down but level, rendered the whole configuration obvious.
It was her side of the Mite that was leading now, so it was her turn to brake the vehicle. She opened her air jet, counting the flickers beneath her fingertips, delivering a blast a little longer than Ivo’s. Their new orbit would be much rounder than the last one, but still sufficiently elliptical for its closest approach to bring them almost to the surface. Skimming above the powderstone plains, they could choose the most promising site and then kill their velocity entirely. Once they had fallen to within arm’s reach of the surface, resisting any further motion would require only the gentlest vertical thrust.
The ceiling of rock began tipping down toward Ivo’s side of the Mite, their descent propelling them around the Object ever faster. Carla found the sense of momentum more empowering than alarming; she’d had enough of waiting. She wanted to see a plain of orthogonal matter spread out beneath her, near enough to touch. This fragment of the primal world had traveled backward around the history of the cosmos; the world that had given birth to her ancestors had taken the opposite course. For a child of one to encounter the other would close that vast, magnificent loop—and the meeting that the Hurtlers offered with violence could here be made serene. With caution, serene.
Ivo took her hand. Did you see that?
What?
The flash, he replied.
Carla looked past him at the jagged brown rock, unchanging in the starlight. Perhaps the Object collided with specks of ordinary dust now and then. It was even possible that some fleck of material from the hull of the Gnat, or a particle of unburnt sunstone from their final burn, had just made its way to the surface.
She saw the next flash herself. It was less fierce than the ones they’d provoked from the Gnat, and much more diffuse—less a blazing pinprick than a brilliant daub of light. An ignition as dispersed as that wasn’t due to a fleck of anything.
What’s doing this? she asked Ivo. He didn’t have time to reply before the surface lit up again, a burst of blue-tinged flame spreading out across the rock, then quickly dissipating.
Us? he suggested.
Carla felt her muscles grow tense with fear, but his theory made no sense. How could they still be shedding anything, after the air had flowed over them for so long? Any loose material in their equipment or on their bodies should have been carried away into the void long ago by the relentless breeze.
What, exactly? she replied.
Ivo thought for a lapse or two, while another flash erupted on his left.
Contaminant in the air, he concluded.
Carla couldn’t see his face, which was turned toward the Object, but his posture was hunched in shame. Ivo had been responsible for filtering all the air they’d packed, ensuring that it contained no particulate matter. She couldn’t imagine him treating the task with anything but scrupulous attention.
But he wasn’t taking the blame for no reason; the symptoms lent his verdict a horrible plausibility. If the Mite’s would-be air shield was actually spraying traces of fine dust in all directions, that would explain why these ignitions were so much more dispersed than the ones brought on by the projectiles.
The flashes were coming every pause or two now, and the wall of rock was drawing closer. Carla struggled not to panic; the single worst thing they could do would be to aim an air jet straight at the surface in the hope of a swift ascent. All their tanks had to be treated as equally suspect: the contents of any of them touching the surface could engulf the Mite in a conflagration.
She made some quick calculations on her thigh. Jet four, six flickers, she suggested. Jet four was pointing back along their orbit; though the burst of air would be aimed horizontally, it would raise their velocity and reduce the curvature of their trajectory enough to cause them to ascend.
What about spillage? Ivo protested.
Can’t be helped. The jet’s nozzle would send out a wide spray, some of which was sure to reach the surface. But if they did nothing they’d remain on their original orbit, passing within a few dozen strides of the rock. The flames were probably reaching at least that high already, and with the source of contamination even closer the eruptions could only become more intense.
Shut off all air? Ivo replied.
Carla hesitated. Would that be wiser than risking the jet? The air shield was clearly more of a liability than a source of protection, but she couldn’t say the same about their cooling bags.
Hyperthermia? she countered.
Shield is worst thing, Ivo pointed out. Bags later, not for long.
He didn’t wait for a reply for the first step; he reached into the center of the Mite and closed the outlet valve on the air tank feeding the shield.
The blue flares persisted, undiminished, for so long that Carla came close to proclaiming that Ivo’s dismal hypothesis was wrong, and that they could use the air jet to retreat with impunity. Then, abruptly, the rock became dark.
Once it had actually happened, it was hard to think of this respite from the encroaching flames as a bad thing. But the fact that Ivo had been right about the cause didn’t mean his minimal air scenario really was the Mite’s best chance. If they did use the jet, how much spillage would there be? How high would the explosion reach? Would it spread out from the ignition site fast enough to catch them?
The truth was, Carla didn’t know. She couldn’t quantify any of these things.
How long, then, could they survive without air drawing heat from their bodies? People who’d lived through accidents in the void rarely had a chance to consult a clock, but Carla had heard claims that the limit was a couple of chimes.
The Object filled half the sky. Her irresolution had settled the matter: they were too close now to risk using the jet. All they could do was follow the orbit down.
Carla could see the plains of gray powderstone approaching, below her to the left but swinging toward her right, the wall of rock tilting and coming full circle. The scale was impossible to judge; she checked the clock. The lowest point on the orbit was still seven chimes away.
A wide, shallow crater slid by, its ancient walls broken like the ruined desert fortress her father had described to her as he recited a story from the sagas. As it passed, flames erupted along part of its rim and spilt across the ground. This was it: the meeting of worlds she’d longed for. With a pang of grief she thought of sweet Carlo, fighting so hard to keep her alive, poring over census records to plan their every meeting.
A trail of blue fire pursued the Mite, streaking across the pitted landscape. The light from it was dazzling, almost painful, but Carla couldn’t look away. Ivo reached up to the tank on his chest and shut off the air to his cooling bag. Moments later the flames subsided, but they did not die completely.