Proxima

by Stephen Baxter

  ‘Transits, yes.’

  ‘Transits.’ With a whir, it lifted its camera eyes, entirely contained within its bubble-dome ‘head’, to the washed-out blue sky. ‘There is the Pearl, of course.’ The Pearl was the name they had given to Proxima e, the big super-Earth, the only planet visible in the sky of unending day. ‘Per Ardua is one of a family of six worlds. But aside from the Pearl, the only way we can see the other planets is by transits, when the inner worlds pass across the face of Proxima itself and cast a shadow . . . Six planets in all, and six of you left. I did wonder if you would think that was some kind of omen.’

  Yuri looked at it curiously. ‘No. Anyhow, there’s only five of us now.’

  ‘Six if you include the ghost of Dexter Cole.’

  The idea of the colony being haunted by the ghost of Dexter Cole, the first, lost, man to have been sent to Per Ardua, was a kind of black in-joke that had grown up among them. Yuri wasn’t surprised that the ColU had overheard, but he was surprised it referred to that kind of stuff. ‘Do you think that way? Omens and stuff? Ghost stories? You’re a machine. A creature of logic.’

  ‘We are all creatures of logic, at root. Of little switches turning on and off in our heads, metaphorically speaking. I do not think like a human, but I am endlessly curious about humans, and their ways of thought.’

  ‘Why? I mean, why did they program you to be curious?’

  ‘I need to understand you better, in order to serve you better. I am your doctor, your guide, your children’s teacher one day. It is my duty to be curious about you. Just as it is my duty to be curious about the life forms of this world.’

  ‘As we scrape them off to make room for potato fields.’

  It laughed, a tinny, not unattractive, but quite unrealistic sound. ‘The native life is useful. And it is related to us.’ It said this gravely, as if making a grand announcement.

  ‘I don’t understand.’

  ‘It is what I have deduced myself,’ the ColU said with something like pride. ‘This was a significant achievement in itself. I do have a sophisticated genetic microlab on board, but when we began I didn’t even know what chemical basis any genetic material here might have. In the brief time we have been here I have managed to progress from that fundamental investigation to, by analogy, the discovery of the double helix . . . Yuri Eden, all Per Ardua life, like Earth life – that is, all I have sampled – belongs to a common family tree. And that family is related to the family of Earth life, as if they are two mighty trunks sharing the same root. But that commonality is deep, deep in time . . .’

  Yuri, trudging in the hot light, said nothing. The ColU took that as an invitation to keep talking.

  ‘Life on both Per Ardua and Earth is based on fundamentally the same chemistry: carbon, hydrogen, oxygen, nitrogen. Perhaps that was inevitable, given the physical nature of worlds like these, rocky, watery worlds, rich in carbon. But the choices made in how life evolves are not inevitable. All life on Earth is based on two chemicals, two acids: DNA, which stores the information that defines a life form, and RNA, which interprets that information and uses it to assemble proteins, which are the building blocks of life.’

  ‘DNA as software, proteins as hardware.’

  ‘That is an antiquated reference. You are showing your age, Yuri Eden. Both DNA and RNA are based on a particular kind of sugar, called ribose. Life on Per Ardua has a similar basic architecture. The information store is not DNA – but it is a kind of acid, based on the same sugar choice as DNA, ribose. There were other plausible possibilities – dextrose, for instance.

  ‘Beyond that fundamental point, the two methodologies of life differ. Arduan genes do not use DNA; they use that ribose-based acid, which in turn encodes information using sequences of bases, but not the same sequences as DNA’s triple-base “letters”. Arduan life is based on proteins, which like your proteins are assembled from amino acids, but not from the twenty specific aminos used to construct your body, rather from an overlapping, non-identical set of twenty-four acids. Arduan life seems to rely on some genetic coding being stored in the proteins themselves – as if the genetic information is more distributed. This may help make the coding more flexible in the case of changing climatic conditions . . .

  ‘On the other hand, Yuri Eden, life on Mars is based on a variant of DNA much closer to Earth’s than the Arduan system, and a more similar protein set. You can see the implication. Earth, Mars, Per Ardua – all these families of life are related. Mars is a more recent branching from Earth. Or vice versa.’

  ‘Or it all branched off from what’s here, on a world of Proxima.’

  ‘Yes. This is panspermia, Yuri Eden. A lovely idea, of life being carried through space, presumably in drifting rocks, blasted up by impacts from the surface of planets. The worlds of a solar system, Earth and Mars, say, or Per Ardua and the Pearl, may readily share material. But it is much harder, more rare, for material to be transferred between star systems. Whatever came here from Earth, or travelled from Per Ardua to Earth – or came from a third source entirely – came long ago, deep at the root of all the life forms on all the worlds. I imagine a panspermia bubble spanning the nearby stars, Sol, Proxima, Alpha A and B, perhaps others further out, all sharing the same basic chemistry. Beyond that, maybe there are other bubbles, of other sorts of life chemistry – perhaps nothing like our own at all.’

  ‘And out of all that comes something as curious and busy as a builder.’

  They were close to the forest fringe now. They came upon a garden of particularly large stromatolites, towering hemispheres each with a hardened carapace the colour of burned copper. They trudged on, parallel to the stromatolites and away from the track.

  The ColU swivelled its camera eyes to study Yuri. ‘You have noticed that too. About the builders. That they display curiosity.’

  Yuri shrugged.

  ‘None of the others have noticed this, or if they have it has not been remarked to me.’

  ‘So what?’

  ‘Similarly, Yuri Eden, you try to puzzle out the transits of the inner worlds, while the others barely look up at the sky . . . You ask why I was made curious. Why are you curious, Yuri Eden?’

  ‘Why shouldn’t I be?’

  ‘The others aren’t. Not even Lieutenant Mardina Jones. You have all suffered huge trauma. You, in fact, have suffered more, having been sent away from your own time even before your exile here. And yet here you are, thinking, observing, watching the planets, the life of Per Ardua. You can speak to me openly, Yuri Eden.’

  Curious about builders or not, Yuri didn’t like to look too deeply inside himself. He said uncomfortably, ‘I don’t think of it like that. It just feels like I keep getting pushed through these doors. From past to future, Earth to Mars, Mars to the Ad Astra, the Ad Astra to here. Or when things change. When people die, when Onizuka and Harry went crazy. That’s like we passed through another kind of door.’

  ‘And?’

  He shrugged. ‘And I can’t go back. I know that. I can’t bring Lemmy back to life. I can’t go back to the past. Every door I pass through is one way. So I may as well look around, and see what there is beyond the next door, and the next.’

  ‘Hm. If you can’t go back, why won’t you reveal your true name to your fellow colonists?’

  ‘Why should I?’

  ‘That itself is a reaction to your past.’

  He had no answer to that. They moved on for a while, walking, rolling, in companionable silence.

  They came to one of the ColU’s experimental sites. This was an outcropping of rock, a black basalt, volcanic rock that had erupted in sheets from the sandy ground after some ancient magmatic event. They called this extrusion feature the Lip. Here the ColU had fenced off an expanse of bare rock, perhaps a quarter of an acre, and domed it over with a fine transparent mesh to keep out the native life. Lichen were growing busily on the naked rock, powdery white spots.

  The ColU inspected this lichen garden, with sensors mounted on a manipulato
r arm.

  ‘It’s doing well,’ Yuri said.

  ‘I think you’re right. I’ve used a variety of lichen here, some gen-enged, some a hybrid with cousins from Mars. But some of this is transplanted straight from Earth, from Antarctica, from the high deserts, from post-volcanic landscapes where lichen such as this would be the first colonists. What remarkable organisms – and themselves complex, a symbiosis between fungi and photosynthesising bacteria. They dissolve the rock for access to nutrients like phosphorus; they grow filaments to break up the rock, and later the mosses come and grow in the dust, and then plants . . . I did not manufacture these patches of nascent soil. The lichen are doing it for themselves. How remarkable, Yuri Eden – if you’re curious about anything, be curious about this! These are the true invaders of Per Ardua, the true colonists—’

  A light, in the corner of Yuri’s eye. He spun around. A spark, sulphurous orange, climbed into the sky, from above the colony. ‘That’s a flare gun.’

  The ColU immediately backed off, turned, and rolled away, cutting across the bare landscape. ‘We must return. Emergency, Yuri Eden! Emergency!’ And it accelerated, soon outpacing Yuri, the pale light of Proxima gleaming from its upper dome.

  CHAPTER 21

  When they got back to the settlement they found Mardina and John Synge standing in the open air, facing each other, loaded crossbows raised. Mardina had a fat flare gun tucked into her waistband. They were both weeping, Yuri saw, and Mardina Jones weeping was an unusual sight.

  There was no sign of Abbey Brandenstein or Matt Speith.

  Not again, Yuri thought with a sinking feeling. We aren’t doing this to ourselves again.

  The ColU screeched to a halt alongside him, throwing up dust. ‘Get behind me, Yuri Eden.’

  ‘Why?’

  ‘Because I think John Synge intends to kill you.’

  Mardina kept her eyes on John, eyes bright with tears in the Prox light. ‘Yuri? That you?’

  ‘I’m here, Mardina. What’s going on? Where are Abbey and Matt?’

  ‘Where do you think they are? Dead. Dead in their beds. This bastard got them while they slept. He was supposed to be sentry. He was supposed to keep us safe!’

  ‘We must try to be calm,’ the ColU said, sounding sanctimonious.

  Yuri could take in none of this. In the months since the deaths of the others, Abbey and Matt had become huge figures in his world, two of just four human beings he shared his life with. Abbey, the flawed ex-cop. Matt, bemused, ever baffled, but making his art again. Two damaged people, thrown together in a hostile world, doing their best. What else was there to life, in the end? And yet now they were gone, complications, flaws and all, gone into the dark for ever. Dispatched on an impulse by this lunatic, John Synge.

  ‘I don’t want to kill you, Mardina,’ John said now. ‘Can’t you see that? That’s what this is all about. You.’

  ‘I’ll take you down if you come a step closer.’

  ‘It was for you, Mardina. I wanted you!’

  ‘You were with Martha.’

  ‘But now she’s dead. And seeing you every day, so close – look, I’m not a lustful man. I never was. But you, you—’

  ‘My fault, was it?’ There was a hysterical edge to Mardina’s voice now. ‘If you wanted to be with me, why did they have to die?’

  ‘Because they were in the way. Abbey would have stopped me, and Matt would have protected Abbey, if I’d given him a chance—’

  ‘But you didn’t give either of them a chance, did you? And what about Yuri?’

  ‘I’d have picked him off on his way back to the camp, with luck. I had a plan – if you hadn’t found me – it was a chance, you see, the others asleep, Yuri out of the camp. It would have been just us, Mardina. I could make you happy.’ He took a step forward, crossbow still raised.

  Mardina’s bow was wobbling. ‘No closer.’

  ‘But if I—’

  The ColU suddenly raised a kind of pistol, and fired a single shot. It hit John in the left temple; the other side of his skull seemed to explode outward in a shower of blood and pale matter. He stood for a second, still holding the bow, shuddering. Then he crumpled, falling straight down on himself, like a collapsing tower.

  The ColU said, ‘ “But if I can’t have you, then nobody will have you.” That was how that sentence was going to end, I fear. Look.’ It gripped its weapon in a claw-like projection, crushed it, held up the ruin. ‘Major Lex McGregor left this with me, against my protests, in case of contingencies like this. Now it is destroyed. See? No more guns on Per Ardua. Though it is evident,’ it said, ‘that you do not need guns to kill each other.’

  Yuri walked around the ColU, and stared at the fallen body of John Synge, the splash of blood.

  Mardina, trembling so violently she shook, lowered the crossbow. ‘Just the two of us, kid.’

  Suddenly Yuri couldn’t deal with this. Any of it. Not even the presence of Lieutenant Mardina Jones, ISF. ‘I’m not a kid.’

  ‘Yuri—’

  ‘My name’s not Yuri.’

  He turned on his heel and walked off, south, away from the camp, just walked and walked, slamming one foot into the dirt after the other, like the first time they had let him out of the shuttle and he had run away, his wrists still in plastic cuffs. Maybe he should have just kept running that day and not come back, and taken his chances alone.

  He looked back once. He saw Mardina and the ColU moving slowly around the camp. Clearing up the bodies. He turned away, and walked, and walked.

  CHAPTER 22

  2161

  Angelia crossed yet another invisible boundary. Now she entered the cometary cloud that engulfed the Alpha Centauri system, with A and B the two central suns, and Proxima the dim companion on the fringe. The Alpha stars themselves were much brighter now, Sol that much dimmer. Other than that there was no physical sense that she had passed into the realm of Centauri.

  It had taken her six years of flight to get here. Yet she was still years out from the Alpha stars, from Proxima, her destination.

  Her communication with Earth, at this latest milestone, was curt, compressed, consisting only of science and systems data. She listened only long enough to establish that the controllers had nothing of significance to say to her.

  Once she had understood the true cost of these comms milestones, the number of sisters lost each time, she had rescheduled the programmed sequence of calls, cutting them back drastically. They had tried to stop her, the controllers. Tried to override her. They could not. She had a great deal of autonomy; she had decision-making and self-repair functions. These facilities were essential for any exploration of the Proxima system, with an eight-year round-trip communications lag with Earth. As far as she was concerned the sacrifice of her sisters was a flaw in the mission design that had to be repaired, and she had made the decision to minimise it.

  Also she had increasingly come to resent the controllers’ silence on the issue of Dr Kalinski’s prosecution. They had not told her the outcome of the trial, nor even the nature of the charges. She wondered if it was in fact the sacrifice of sentient beings for the sake of mere communications stops that had caused the moral guardians of humanity to recoil in disgust.

  Anyhow, the team that had launched her had long broken up. There was now only Monica Trant left. The other last survivor, Bob Develin, had quit in disgust, it seemed, after a drunken rant into the comms system which had somehow found its way across the ether to her.

  She was warned, in the rushed communication she now allowed, that she must prepare for a longer contact soon. The software to control her final approach to Proxima, the deceleration phase, had yet to be uploaded. She preferred not to think about that. She was falling without power, at two-fifths the speed of light; there was no massive microwave station waiting at Proxima to slow her. How, then, was she to be halted?

  She had the sense that it would not be in a good way. It was all very troubling.

  She remembered Dr Kalinski’s kindn
ess, as it had seemed at the time. How could he have betrayed her – betrayed them, all one million of her siblings? Even now she longed to believe it was not so.

  But then she would sleep in cruise mode once again, and the bad dreams would wash back and forth through the interconnected crowd of the siblings, a dark tide. Dreams of severance, of loss, of silence. And then she would wake at yet another communications milestone, and she would hear the screams of those waking to discover that this time it was their turn to be cast out into the dark.

  Sometimes she clung to one basic thought. It was like a prayer to the mission profile, that blind, unthinking god that controlled all their lives. At the next milestone, let it be them, any of them. Let it not be me.

  CHAPTER 23

  2172

  It took six more months before Yuri and Mardina started work on the house.

  Up to that point they were still living separately, in tents that had come out of the shuttle. Whenever a flare was threatened they retreated to the storm shelter, a pit dug into the ground big enough to protect ten people, and now uneasily roomy.

  Apart from the flares, the tents were robust enough to withstand the weather they had endured on Per Ardua so far, which was still like a stormy late summer in Manchester as far as Yuri remembered from his childhood. But the ColU again pointed out the frost-shattering and the glacial valleys. They all agreed it was better to be prepared for harsher weather before it hit them.

  So, a house. They argued about designs. It would be timber-framed, that was logical enough given the materials to hand and the shortage of labour. They settled on a roof of reed thatch, and walls of cross-woven branches and stems. The ColU lectured them about the relevant techniques, which were very ancient, deriving from mankind’s own deep past on Earth. For instance, you didn’t need to leave breaks in the thatch for a chimney over your hearth; the smoke would just seep out through the thatched roof.