Greg Egan - The Eternal Flame

Tamara closed three eyes and pressed the fourth to the instrument. The ellipse was now a crisply rendered, idiosyncratic oval with a pinched and tilted waist. About a third of one lobe was as red as firestone, but the rest bore patches of brown, of gray and of white. Everything was pale and subdued in the starlight—and any comparisons she made with the sight of mineral samples in a well-lit workshop or storeroom would be unreliable—but the brown outcrops more or less matched the calmstone slopes of the Peerless , viewed under similar conditions. There was a sprinkling of small impact craters everywhere—structures Tamara had only ever seen before as sketches in astronomy books, recorded by the ancestors when they’d observed the inner planet Pio.

“We finally have our own sister world,” she said.

“Sister or co?” Ada replied.

“It almost matches us in size,” Carla pointed out. “A co should be smaller.”

Ivo said, “It’s what happens when the two come together that counts.”

“Either way,” Tamara said, “it doesn’t look like a stranger.” After three generations alone in the void, the travelers could hardly dismiss any companion as mundane. But these rocks did appear to be ordinary rocks, old and pitted as they were after a long journey. If their origins really could be traced all the way around the history of the cosmos, back to the primal world’s past-directed disintegration, that only made their similarity to the stuff of the Peerless all the more striking. Matter was matter, shaped by the same rules and forces everywhere—and it looked no different even when you encountered it backward.

Two small burns nudged the Gnat ’s trajectory toward the rendezvous point. The crew kept returning to the telescope as the Object’s slow spin revealed its whole surface: more of the same minerals, more small craters.

“The only thing missing is life,” Carla said. “Not one patch of weed, not one speck of moss.”

“Pio, Gemma and Gemmo were dead worlds too,” Tamara reminded her. “Chemistry might be universal, but life must still be rare.”

Ivo took his turn at the eyepiece. “Forget life,” he said. “I’d be happy with any sign of rubble.”

Tamara felt the same. If the Object had been nothing but a loose pile of stones then they would have had no hope of altering its trajectory—but enough fragmentation to save Ivo from having to chip off samples himself would be a huge advantage. The Object’s spin was slow enough that even its weak gravity could, in theory, maintain a tenuous grip on pebbles scattered across its surface, but the creation and persistence of such things would depend on the whole detailed history of the body. Over time, the radiation pressure of starlight should have pushed away the very tiniest dust grains, but that was no loss: anything too small to see and avoid would only have posed a hazard.

While Tamara had been locked away on the farm, Ivo had been working on his sampling techniques. By now he was able to get decent results with powderstone as the target and pure air as the blade, and with calmstone as the target and traces of hardstone in the airflow to act as an abrasive. The first was easy enough, but the second could take more than a day.

He had also tried to carve firestone using air flecked with its liberator. Burning furrows into the firestone hadn’t been a problem, but getting an intact sample free of the main body had proved impossible.

People had been studying firestone since antiquity. But if Ivo had to hack a piece of the Object loose using its own kind of fire as his only cutting tool, he would need to learn to do it in a matter of days.

The deceleration was planned to take place in three stages. Tamara put aside every distraction and devoted herself to the navigator’s arts. She didn’t care about the jagged beauty of their companion world any more; all that mattered was the geometry and timing of the encounter.

The first and longest burn rid the Gnat of most of its velocity relative to the Object—but it was impossible to aim the engines perfectly, and observations soon revealed that in slowing the craft they’d also pushed it slightly off course.

Tamara tweaked the second burn to compensate. It would add its own errors, but the thrust would be less and the consequences smaller.

Before the third burn, she and Ada spent half a day sighting and re-sighting beacons and following the Object’s slow drift against the stars. Their target was growing visibly larger by the bell now, and though they were aiming for a suitable offset a small mistake could see them slam right into the rock. Tamara was duly meticulous—but it was hard to resist a kind of sneaking pride in the thought that it wouldn’t be the worst way to go. For the Gnat to become lost in the void would have been humiliating—quite apart from the unpleasantness of hyperthermia—but if they actually hit this lonely speck after crossing such a vast distance, their demise would at least be a testament to their almost perfect navigation.

Tamara set the clockwork for the burn, and when Ada had checked the dials she checked them again herself. She strapped herself into her couch and, for the first time, closed her front eyes.

The couch pushed against her back, the shuddering of the engines penetrated her bones. The glare of the exhaust came through her eyelids, two giant gray stars blossoming in the darkness where the windows would have been.

The gray stars faded. Tamara opened her eyes, took off her helmet and unstrapped herself from the couch. As she crossed the cabin, the Object’s now familiar terrain filled the view through the window on the left—neither approaching nor retreating, giving every appearance of perfect stillness.

That was impossible, but inasmuch as any one moment could be called an arrival, this was it. Trying to steer the Gnat into a well-defined orbit once and for all would have been too ambitious; the tug of the Object was so weak that orbital velocity and escape velocity were just two different kinds of brisk walking pace. But with careful observations and the odd gentle push from the air jets, they ought to be able to weave back and forth between a safe altitude and an unintended departure.

It was Carla who rose first to join her, chirping with delight at the landscape suspended below. “Well done!” she said, turning to include Ada.

Ada said, “Now that we’re here… why not just rest for a while, then go back and break the news that the Object was inert?”

She was joking, but the proposal did have a certain mischievous appeal. “We could probably get away with it,” Tamara replied. “Silvano might try to send a follow-up mission, but I doubt he could persuade the Council to back it. Dragging some giant self-contained engine, big enough to capture this by brute force…?” She swept an arm across the alarming arc the Object now subtended.

Ivo said, “They’d never do it, you can be sure of that. Our own plans are quite insane enough.”

24

Carla helped Ivo attach his spectrograph to the telescope, then watched him load the first sample into the catapult beside the window: the first small irritant with which they hoped to goad the Object into a revelatory response. The Gnat had no airlock as such—nothing large enough for the crew to come and go without depressurising the whole cabin—but Marzio had designed a miniature version, equipped with lever-operated scoops and pincers, that allowed them to move these tiny samples the short distance through the hull and into the catapult’s launch tube.

Back when the surface of the Peerless had been suffering the sporadic flashes attributed to orthogonal dust, no one had ever managed to observe—let alone record—the light’s spectrum. Before the centrifugal force of the mountain’s spin put an end to those displays, people had proposed spectrographs with such a wide angle of view that the inability to know precisely where the light would be coming from would cease to matter. The problem they’d never solved, though, had been the question of timing: no one could react quickly enough to open a shutter just as the flash occurred, and a prolonged wide angle exposure, even if it encompassed one of the rare events, would bury any signal from the flash itself in the accumulated background of reflected starlight.