The Eternal Flame

by Greg Egan

  “The only practical means to advance this program known to the Council is Carla’s proposal to develop a coherent light source. Accordingly, we ask her to submit a detailed schedule of resources and personnel for approval.”

  “Congratulations,” Ivo whispered.

  “Since the other proposals put to us today are all contingent on the same technology,” Giusta continued, “we will defer any decision in those cases until Carla’s team are able to report on the success or failure of their efforts.”

  Carla was ecstatic. As the Councilors departed she stood swaying, listening to the good wishes of Ada and Tamara but unable to respond.

  The lights of the chamber flared, becoming painfully bright. Carla tried to close her eyes but if she succeeded it made no difference. A voice addressed her from the whiteness. “Are you all right? Carla?” Someone put a hand on her shoulder, shaking her gently.

  The lights faded. Tamara’s face was in front of her.

  “I’m fine,” Carla managed. “Things just took me by surprise, that’s all.”

  29

  Carlo checked the viewfinder on the infrared recorder; the subject had moved a little off-center, but it remained in sight. Amanda had done her best to confine the lizard without alarming it, leading it with a series of treats into a twig-lined nook in its cage and then inserting a slender branch across the only easy exit. With a mound of freshly killed mites in front of it, discouraged from scampering away but not literally trapped, there was nothing compelling it to respond to the events that followed in anything but a natural manner.

  “Ready?” Macaria called from the corridor.

  “Ready,” Carlo replied.

  Macaria dragged herself slowly into the room, three hands on two guide ropes and the fourth holding out a cage. A sufficiently timid passenger could be unsettled by any mode of transport, but Macaria was advancing as smoothly as possible, and the animal had been given a chance to grow accustomed to the process, having been moved from room to room this way every few days for the last two stints.

  Carlo started his recorder. Amanda waited for Macaria to clamp the second cage onto the guide rope, less than a stride from the first, then she aimed her own recorder squarely at the new arrival before starting the paper whirring through. There was a clear line of sight between the lizards now; Carlo couldn’t swear that his subject’s single pair of darting eyes had turned far enough away from its food to take in its distant cousin, but preoccupied or not it could probably smell the other animal. In any case, the infrared channel alone might be enough: Macaria had proposed that the lizards regularly sent out faint kin-group identifiers, too weak and sporadic to show up on her images but enough to initiate a more vigorous exchange once they were detected.

  They let the recorders run for six lapses, exposing as much paper as the spools could contain.

  “It looked as if they barely noticed each other,” Carlo said.

  “What were you expecting?” Macaria replied. “This species doesn’t show much aggression unless they’re jostling for the same scrap of food, and they’re not potential mates in any conventional sense.”

  Carlo began rewinding his spool. “Doesn’t it seem strange, though? Sharing notes about the future of your offspring without even looking up from your meal?”

  Amanda said, “Were people on the home world ever conscious of the fact that they were exchanging influences?”

  “It’s hard to say,” Carlo admitted. “The history of the subject is so vague.”

  Amanda mounted her own spool on the bench. “We might still be doing it ourselves. Even without geographical isolation, it’s not as if everyone on the Peerless mixes daily with everyone else. We can still encounter strangers.”

  “Hmm.” Carlo pondered the unsettling notion that his own children might be altered somehow if Carla bumped into a reclusive herb gardener—perhaps lured from his cave by rumors of an unusually well regarded variety show.

  The paper from his recorder was still blank so far, apart from the metronomic time codes along the edge; either the exchange had been over when he’d stopped the recorder, or it had never begun. Macaria’s original experiments had involved two large groups, but she’d decided to try capturing the time sequence from pairs of individuals, both for the sake of simplicity and to avoid squandering future opportunities. Once two lizards had been exposed to each other the infrared traffic between them was expected to die away, quite possibly for the rest of their lives.

  “Ah, here it is!” Carlo’s tape was marked now, with a complex series of dark bands. The pattern itself did not look familiar, but the general time scale, revealed in the typical length of each feature, was comparable to that of the internal signals he’d recorded from his own body.

  Amanda kept winding until she reached her lizard’s contribution. They’d made less effort to keep the second animal confined, so the bands were fainter and the pattern sometimes faded out completely.

  Macaria didn’t seem to care; she just turned excitedly from spool to spool, giddy at the sheer surfeit of information. “What do they do with all this?” she wondered. “If it really does encode a set of traits, they can’t just give their offspring every trait that lands on their skin.”

  Amanda said, “Maybe there’s some kind of counting going on. If a trait’s being sent out by a majority of the strangers you meet, and they seem to be in good shape, maybe that makes it worth adopting. If all these other animals have used it and thrived, why not take advantage of their experience?”

  “That sounds like a great way to kill off your rivals,” Carlo suggested. “Live your own life, construct your own body one way, but send out the code for something else entirely. Gang up with your cousins so you all repeat the same lie, pretending you’re offering the newcomers the secret to good health when you’re really spreading something that will poison their children.”

  “But then the code won’t spread far,” Amanda countered. “I mean, the lizards aren’t consciously planning any of this. A code that kills rivals might give some benefit to the animals who send it out, but a code for a genuinely useful trait would end up being copied far more widely.”

  “The way direct inheritance selects useful traits,” Macaria said. “Only these ones spread horizontally, ignoring the family tree and leaping between branches that separated before the trait was invented.”

  “So can an influence make you sick or not?” Carlo wondered. “Is that real or just folklore?” He thought for a while. “What if a code isn’t necessarily fatal, but it forces you to send out copies of itself? That would divert resources from other things your body should be doing—so it could certainly weaken you—but so long as you spewed out enough copies in a form that other people would absorb and act on, the code would spread like wildfire.”

  “Maybe there are both kinds,” Amanda conceded. “Good and bad influences, just like the folk belief.”

  “I always thought bad influences would turn out to be like plant blights,” Carlo admitted. “Something solid spreading through the air, not messages encoded in invisible light.”

  “We haven’t actually shown that infrared signals can carry disease,” Macaria pointed out.

  Amanda said, “So we should find some sick voles and see for ourselves if they’re putting out bad influences.”

  “Voles?” Carlo was confused. “Why change species? We don’t know if voles use this kind of signal at all.”

  “Lizards hardly ever get sick,” Macaria explained. “Or if they do, it’s impossible to tell.”

  At the breeding center, Sabina was happy to oblige them. “I’ve got five families of voles in quarantine. Take your pick.”

  “Can we take three?” Amanda asked. “We’ll bring them all back in a couple of bells.”

  “Bring them back?” Sabina was confused. “Who’s going to want them for a second experiment?”

  “We’re not going to lay a hand on them,” Macaria explained. “We just want to observe them.”

  They
carried three cages back to the workshop, a male and four children in each. Carlo felt sorry for the listless animals, though he’d done much worse to their relatives than disturb a convalescent’s rest.

  The recordings from all three families were blank. Carlo was ready to give up, but Amanda said, “They’ve been sitting in quarantine together for days. They’ve already influenced each other. Why keep sending out the code for no reason?”

  Carlo said, “What about us? We’re not worth infecting?”

  “Maybe the influence doesn’t bother trying to cross species,” Macaria suggested. “Or maybe it did try early on, when we picked out the cages.”

  Amanda said, “Load the recorder again. I’ll go and get a healthy vole.”

  She returned a chime later with the bait, almost re-enacting Macaria’s entrance for the lizard experiment. These voles had not been bred apart, though; they’d all been raised together until the sick ones were removed, so any signal they exchanged now would not be due to a lack of familiarity.

  When Carlo rewound the tape it was covered in dark bands. His skin crawled. This was it, right in front of him: a disease that could leap through the air from victim to victim as infrared light. The voles had merely been weakened, but there was a chance that the very same kind of pattern had pushed his father to the point of death.

  “Why not ignore every code?” he asked. “Why would our bodies risk harming themselves?”

  “The trade-off must be worth it,” Macaria said. “There must be beneficial traits circulating as well. The catch is, how do you know which is which without trying them out?”

  Carlo said, “So… some traits we pick up don’t get expressed until the next generation. We come across a healthy-looking group of strangers, exchange advice with them in infrared, and try some of it out on our children. If everyone’s being honest, there’s a good chance that everyone benefits.”

  “But then the system was hijacked,” Macaria conjectured. “Someone sent out a code that acted immediately on the recipient, forcing them to send out copies of itself. And maybe we developed some defenses against that… but it turned out to be advantageous not to shut off the process completely. We hijacked the hijacked system, at least enough to make it useful sometimes.”

  “And all of it by chance.” Amanda buzzed softly. “No malice in it, or beneficence. Just accidental success.”

  Carlo wound the tape back further, looking for the start of the sequence. If he could identify the part of the code that made an animal accept that the whole thing was worth trying, then cut that out and splice it onto instructions to the body to give birth to exactly two children… would that work? No one had ever reported an influence like that, but then, even if such a sequence had come into existence there’d be no reason to expect it to persist. What could be found in nature would be a tiny subset of what was biologically possible.

  He reached the start, and examined the innocent-looking stripes. Do whatever follows—was it as simple as that? No doubt some voles had learned to ignore this particular directive, but for those who had succumbed it was apparently as hard to resist as the patterns passed down through their own flesh.

  Carlo said, “We need to keep studying this process in voles, but their biology is still too distant from our own. We should use them whenever we need a short breeding cycle, but their bodies are so small that the internal signals are always going to be hard to collect.”

  Amanda said, “Lizards don’t grow much larger, and we have even less in common with them.”

  “I know.” Carlo glanced at the vole she’d brought in; it was already looking subdued as its body followed the instructions imposed on it. “We need to scale things up, and move closer on the family tree. We need to go and capture some arborines.”

  30

  “Mirror balls,” Tamara told Marzio, unrolling the plans across his desk. “Take a sphere, and cover it with small, planar mirrors. That’s it: no fuel to replace, no moving parts, nothing to align or orient. All we need to do is get enough of these in position while the old beacons are still visible, then we can set up the whole grid using nothing but the Gnat.”

  Marzio looked over the sketches. “You do recall that mirrors tarnish faster in the void?”

  “We haven’t forgotten,” Ada replied. “But we’ll only be illuminating these things for a tiny fraction of the time they’re out there. When they’re in use we can limit it to periodic flashes—longer than the old sunstone ignitions, so they’re harder to miss, but pulsed, so the total exposure time for the mirrors is less. And when nobody’s flying we’ll just shut down the beams completely.”

  “What’s more,” Tamara added, “if Carla gives us a choice of frequencies we can opt for something at the blue end of the spectrum. That will cut the tarnishing rate even more. If we can get the drift speed low enough, these things could be in service for generations.”

  “Hmm.” Marzio still didn’t seem happy. Tamara suspected that he found the new design almost insultingly simple; the old beacons had been triumphs of precision engineering, but now she was asking him to supervise the gluing of reflective shards onto a gross of identical spheres.

  “The real challenge will be keeping the beams on target,” Tamara reminded him. If the beacons themselves looked like toys, the machinery required to illuminate them would still demand the skills of a master instrument builder. “But we can’t make much progress on that until we have a prototype of the light source.”

  “No.” Marzio smoothed the sheet and pointed to the core of the sphere that Tamara had drawn in the dissected view. “The choice of materials here is going to be crucial, if you want the mirrors to survive a couple of generations without air cooling.”

  “Right.” Despite their lack of moving parts, the beacons would gradually gain thermal energy from purely optical effects. But it would be better to give the spheres enough heat capacity to slow their rise in temperature than to add the unwelcome complication of an active cooling system.

  Marzio said, “Leave this with me, let me think about it.”

  Halfway back to the observatory, Ada turned to Tamara. “If you’ve got time, we should make a detour here. There’s someone I’d like you to meet.”

  Tamara understood her meaning immediately. “You could have warned me,” she protested.

  “And given you the chance to think up an excuse?” Ada teased her. “You didn’t object when my father offered to make enquiries for you. You can’t say this has come as a surprise.”

  “I was only being polite to Pio,” Tamara said. “I never thought he’d actually find someone.”

  “Your father found Tamaro a co-stead, and they’re both in prison.”

  “Tamaro has an entitlement.”

  “And Livio has an entitlement,” Ada replied. “Not all widowers give up and sell them.”

  “No—the smart ones find widows with entitlements of their own, then they sell the spare one when the children are born.” Ada was already leading them down a side corridor; escape was looking increasingly unlikely. “What does this Livio do?”

  “Masonry. Construction and repairs. Actually, he was in the crew that built the airlock for the Gnat.” Ada hesitated, then added jokingly, “So he’s hardly a stranger. You already have that connection.”

  Tamara didn’t reply. She and Tamaro had been raised side by side from birth, expecting to remain together to the end. No arrangement of convenience with a co-stead could replace that. Whether or not Tamaro’s betrayal proved that she’d been fooling herself all along about the nature of their bond, she would never feel as close to anyone again.

  Ada navigated the way to the masonry workshop, far enough from the axis for gravity to keep the dust under control. Tamara was relieved to find that her suitor hadn’t contrived to meet her on his own; half a dozen people were busy in the workshop, shaping and polishing blocks of calmstone.

  Ada approached one of them, a short, robust-looking man. He shut off his grinding wheel and removed his safety viso
r.

  “Tamara, Livio.” At least Ada’s introduction was discreet.

  “Pleased to meet you,” he said.

  “Likewise.” Tamara faltered. Forewarned, she might have had a chance to think up a suitable topic of conversation, but after Ada’s minimal briefing what could she ask this man about? The death of his wife?

  Livio said, “It must have been exciting, going out there in the Gnat.” His enthusiasm seemed genuine, and Tamara was grateful that his opening gambit hadn’t been to offer his commiserations on more infamous events.

  “It was glorious,” she said. “The experience of a lifetime.” She glanced at Ada, willing her equally experienced co-navigator to chime in with some anecdote from the journey and take the pressure off her. “I’m hoping to do some more flights soon—but I doubt I’ll ever see anything to compare with the first big explosion we raised on the Object. There was so much burning smoke stretching out from the impact site that it was visible from the opposite side.”

  “I’ve worked out on the slopes a bit,” Livio said. “It’s beautiful, just looking down into the stars. But I hope my children get a chance to cross the void. We can’t stay cooped up in this rock all the time.”

  “No.” Tamara didn’t want to believe that he’d feign these sentiments merely to put her at ease. “It was just dumb luck that I saw the Object first,” she admitted. “That’s the only reason I ended up on the Gnat. But what I’m trying to do now is make travel away from the Peerless as easy as possible. Maybe for the next generation, instead of the lotteries it will simply be a birth right: everyone gets to make at least one trip.”

  Livio chirped approvingly. “I like that idea.”

  Tamara said, “I should let you get on with your work.”

  “All right.” Livio hesitated. “Can we meet up again? Share a meal, perhaps?”

  He didn’t suggest a time, knowing she’d have her own schedule for eating. “Tomorrow, around the sixth bell?” Tamara proposed.