The Medusa Chronicles

by Stephen Baxter

  “It is anticipated that at a depth of approximately twelve thousand kilometres, where the pressures will approach one million Earth atmospheres, I will reach an interface to a realm of different physics, and my design will come under fresh challenges.

  “For now, however, I am comfortable.”

  26

  It was Trayne who first noticed the anomalous radio signal.

  Falcon was listening to the transmission from Orpheus with a mixture of wonder and envy. “‘For now, however, I am comfortable.’ Textbook laconic. By damn, you’d swear Orpheus was as human as Young or Hilton—and as cold-blooded.”

  “Maybe,” Trayne said, frowning, distracted. He pointed to a display. “Commander, look at this. One of your filters is picking up another signal. Nothing to do with Orpheus. Is it one of your medusae?”

  Falcon looked over to the screen. Indeed, pulses of shortwave radio transmissions were being detected by the Ra’s huge antenna arrays, and he immediately recognised the basic modulation pattern. Hastily he locked in the translation software suite he had patched together over the decades—the centuries, now—of his contact with the inhabitants of Jupiter.

  Trayne said, “I can’t tell how remote the source is.”

  “I can guess from the signal strength, and we’ll have triangulation soon . . .”

  A synthesised voice, soulless, sexless, without inflection, gave the first rough translation of the signal. The Great Manta has returned. The Great Manta is among us. Pray to the Great Manta that you are spared. Pray to the Great Manta that you are not spared . . .

  Trayne’s eyes were wide. “Is that . . . ?”

  “A medusa. You bet it is.”

  “And I bet I know who it is—that is, which medusa. Ceto, yes? The one we encountered before. “The Great Manta.” You said she was talking about that. It had something to do with a medusa’s ideas of death and extinction?”

  “Yes—an ambiguous myth. Medusae are sentient prey animals. They understand that they are locked into a wider ecology in which the mantas and other predators play an essential role. So they accept the loss of a proportion of their own kind, a toll they pay to the ecology that sustains them—and yet at the same time they will pray to a manta to spare themselves, just for today . . . Something’s happening. She’s in trouble.” He hesitated. “She’s calling for help. My help. She wouldn’t be shouting in the shortwave band otherwise.”

  Trayne eyed him. “And you want to help her, don’t you?”

  He grimaced. “Why? Because that’s what your kids’-story version of a hero would do? Abandon his post and go dashing off to a damsel in distress?” A damsel two kilometres wide . . .

  Trayne looked faintly offended. “No. It’s just that I know you, at least a little. And if she’s calling for you, maybe the trouble she’s in has something to do with humans.”

  Falcon hadn’t thought of that. He said grudgingly, “You may have a point. We’re narrowing the fix. She’s many thousands of kilometres away. Even if we broke away, how could we get there in time? The Ra, like the Kon-Tiki, is basically designed to float around on the wind, not set speed records.”

  Trayne shrugged. “So we cut away the lift envelope. The gondola has its own fusor propulsion system—”

  “Designed to take us out of the atmosphere and back to orbit, not for jaunts in the cloud banks.”

  “Sure. But there’s plenty of spare energy. And the engine is a ramjet—it uses the external air as reaction mass—so it’s not as if we are going to run out of propellant.” In response to Falcon’s surprised look he said more hesitantly, “I checked out the Ra’s specs before we set off from Amalthea.”

  “You did, did you?”

  “I’m not some pampered Terran, Commander. I’m a Martian. I grew up under a plastic dome on a planet that will kill me as punishment for the slightest slip. Of course I checked.”

  “Okay. I’m reluctantly impressed. But we have a mission here. We’re a relay station for Orpheus—”

  “The envelope can station-keep. It has a backup comms systems of its own. Besides, even without us, the signals from Charon 2 are probably strong enough to be picked up directly by Charon 1 back at NTB-4.”

  “You checked all this out too, right?”

  Trayne grinned.

  Falcon turned to his controls. “Okay. You asked for it. Checking deuterium-helium-3 ratio . . .” Restraints locked down Falcon’s frame, fixing it tightly to the structure of the Ra. Make sure you have your exposit powered up and locked into its frame, I’m not going to be sparing the acceleration.”

  “Wouldn’t dream of asking you to.” Trayne backed up to his suit’s wall station.

  “Checking jet chamber temperature.” Falcon glanced over his instruments one last time. Then he broke the safety seal over the ripcord button. “Lighting the blue touch paper.”

  “The what?”

  “Never mind.” He pressed the button.

  There was a sharp crack as explosive bolts separated the gondola from the gas envelope, a brief sensation of falling—they were already committed to this jaunt—and then the ramjet drive cut in. Acceleration pressed. The gondola had turned into an independent craft in the Jovian air, a candle riding a column of superheated hydrogen-helium.

  “You okay, Martian?”

  “Never better.”

  “Liar. I’ll get our trajectory locked in. And I see Amalthea Control is already demanding an explanation. I’ll let you take care of that . . .”

  27

  “My name is Orpheus. This telemetry is being transmitted via radio signals received by Charon 2 at the hydrogen gas-liquid interface, relayed via the Ra at the thermalisation layer to Charon 1 at Station NTB-4, and then to Mission Control on Amalthea. I am in an excellent state of health and all subsystems are operating normally. I remain fully cognisant of and fully committed to the objectives of the mission.

  “At twelve thousand kilometres down, I have passed through the hydrogen ocean, and reached the region known in the theoretical models as the ‘plasma boundary layer.’

  “Essentially, below the upper clouds Jupiter is an immense droplet of hydrogen and helium, all the way to a core of still-unknown composition. I have now reached a depth at which the temperatures are so high that molecular hydrogen cannot survive—where electrons are stripped from their atomic nuclei by heat energy. The resulting plasma is electrically conductive, as is the greater ocean of what is known as “metallic hydrogen” into which I am now descending—it is indeed like an ocean of liquid metal. It is thought that the substance of this sea, by the way, may be useful, perhaps as a room-temperature superconductor, or a high-energy-density fuel . . . All that for the future.

  “The plasma layer, however, will block radio transmissions. Therefore I am depositing another relay station at this depth—Charon 3—and to communicate further I will be returning small buoys that will rise to this depth and contact Charon 3 for further relay of information back to Mission Control.

  “This communication method is one-way.

  “You will not be able to speak to me. I will not be able to hear your voices.

  “The plasma layer itself, as some theoreticians predicted, is a place of marvels. The seepage of carbon, silicon and other heavier elements from the cloud layers has reached even this far, and I have detected many complex, even previously unknown molecular forms and compounds . . . Such materials, mined from this layer, may have many useful properties.

  “But I have time only to note these phenomena. I fall into a sea of metallic hydrogen over forty thousand kilometres deep. This is an arena of huge electromagnetic energies, which I can already sense.

  “As if I fall into troubled dreams.”

  * * * *

  Falcon followed the news of Orpheus’s descent, even as his own fusion-drive craft rocketed through the Jovian clouds. And he listened to the conve
r­sations of the analysts at Amalthea Control, who were becoming increasingly concerned about some aspects of Orpheus’s ­communications—notably the increasing subjectivity of the reports, and the use of words like “dreams.”

  During his involvement with the Machines’ early development, Falcon himself had studied the theory and history of artificial minds. Like that of all Machines, Orpheus’s “brain” was essentially a Minsky-Good neural network, capable of learning, growth, adaptation—a design whose theory went back to the work of twentieth-century pioneers like John von Neumann and Alan Turing. And Orpheus, like any sapient, artificial or otherwise, was vulnerable to instability, especially given an overwhelming experience such as he was currently enduring.

  The cyberneticists on Amalthea and Ganymede speculated that a combination of information overload, personal peril, and solitude could compromise the Machine’s ability to fulfil his primary functions. They even spoke of the danger of him falling into a Hofstadter-Möbius loop, a kind of psychopathy not uncommon to goal-seeking autonomous ­systems when faced with an overload of information and choices. And security officials spoke darkly of the need to debug any copy of Orpheus’s mind that might be returned to the data banks of the inhabited moons.

  Falcon, who was not so prone to seeing a divide between biological and artificial consciousness, had a simpler diagnosis. In people, he had seen similar reactions in those he had guided through the world of the medusae. Even old Geoff Webster had had doses of it, on his good days.

  Awe. That was what Orpheus was experiencing. Awe.

  And the mother hens on Amalthea could do nothing about it now; Orpheus could hardly be brought back.

  As for dreaming, Falcon had long ago come to believe that, like all sentient creatures, Machines could dream. Even if few of them admitted it.

  28

  Trayne, his eyes more youthful than Falcon’s—and probably more recently upgraded—was the first to spot the medusae, in a wide-angle viewscreen. “There!” He pointed, excited, though he winced as his arm rose, fighting the gravity with a whine of servomotors.

  Falcon looked more closely. Against the tan wash of Jupiter’s deeper cloud layers, he saw a curving line of pale oval forms, like a string of pearls in the air. The sun was setting on another short Jovian day, and those pearls cast long shadows. Medusae, surely.

  But they weren’t alone. Sparks of light flitted around them, bright in the fading light, like fireflies. They were nothing natural; they looked to Falcon like fusion torch ships. And ahead of the line he made out a darker knot, some kind of floating factory supported by a dense forest of balloons.

  “What the hell are we looking at?”

  Trayne stared ahead. “Those pods are medusae, right? Which one is Ceto?”

  Falcon glanced at a scanner; Ceto had by now been triangulated precisely from her characteristic radio call. “The third in line—the third from that floating complex.” He glared at Trayne. “You seemed very eager for us to come here. Was it more than just curiosity? Do you know something about this?”

  Trayne looked back at him defiantly. “I’m . . . not sure. That’s the truth.”

  After a beat, Falcon turned away. “Okay. I’ll accept that for now. So we figure it out for ourselves.” He pointed to the screen. “This is not the way medusae behave in the wild. If you’re a prey species, you don’t string out in a line waiting to be picked off. You bunch up in three dimensions, because in this ocean an attack can come from any direction. Secondly, we are far from their usual ranges for food, breeding . . .”

  Light flared against the flank of one of the medusae in the line, like a fusion spark—dazzling, despite the viewscreen’s filters.

  “And what was that? It looked like they deliberately burned a medusa with a plasma jet.”

  Now there was a noise, a deep thrumming, almost like separate impacts, that made the hull shudder.

  Trayne looked at Falcon, alarmed. “Some kind of malfunction? A storm?”

  “No. Wait and listen.”

  The drumming came faster and faster, the individual beats at last merging into a deep wash of noise that grew louder and louder, though it did not increase in pitch, becoming a kind of throbbing bellow that forced Trayne to clamp his hands over his ears—before it cut off with brutal suddenness.

  The gondola seemed to rattle. Trayne lowered his hands, cautiously.

  “That was a medusa. Would you believe that the acousticians call it a ‘chirp’? Sorry, I should have warned you. That was the cry of a medusa in pain.”

  Abruptly an alarm sounded, another grating clamour. Falcon cut it off with a bunched fist. “And that was a proximity alarm. Another craft approaching.”

  Trayne checked the sensors. “It’s already reached us, it’s keeping pace with us.” He looked afraid for the first time since they’d left Amalthea.

  A comms screen filled with a human face, a stern older woman. “I am Citizen Second Grade Nicola Pandit. I have locked into your systems. I have the capability to override your drive controls.”

  A Martian, then. Falcon was furious. He turned to his consoles and quickly set every camera and sensor he had to record, and initiated an upload data stream to Amalthea and Ganymede. Let them see everything.

  Then he thundered, “By whose authority do you challenge me? This is the Ra, a science vessel registered with the Brenner Institute and with the Space Development Secretariat, Bureau of Planetary Exploration. And my name is Howard Falcon. Override me? I’d like to see you try.”

  “You will come no closer to the facility. You will turn back, Howard Falcon, and return to your station for the Orpheus mission—”

  “Like hell I will. Not until I know—”

  “Councillor Pandit?” Trayne was leaning down to see. “Is that you? What are you doing here?”

  “Good grief. Do all you damn Martians know each other?”

  Pandit pursed her lips. “Citizen Third Grade Springer, it is better if you are not involved in this.”

  “I’m already involved, Councillor.”

  “Then you will share the consequences of any actions Howard Falcon takes.”

  Falcon said, “This is my fight. My world. You don’t need to do this, Trayne.”

  “I think I do,” Trayne said, almost sadly.

  Pandit snapped. “I say again, Howard Falcon. Turn back. If you do not—”

  “What? What will you do? Citizen, I’ve been looping loops around the clouds of Jupiter since before your grandpappy was thrown aboard a convict scow to Port Lowell. Catch me if you can; I’m going to take a look at what you’re doing here.”

  He worked his controls, and the gondola surged forward with renewed acceleration.

  “Commander Falcon—!”

  Falcon tapped a console to silence Pandit’s angry voice.

  Trayne said, “They never sent convicts to Port Lowell, you know, Commander.”

  “I was insulting her, not giving her a history lesson. Okay—we’re approaching that complex. There are more ships buzzing around us, but they can’t touch us, not this close; a missile strike on our fusor pod would cause a detonation that would take half that installation down with us. Now, let’s see what’s really going on here . . .”

  He brought the Ra to a shuddering halt, set up station-keeping attitude thrusters, turned the hull to its faux-transparent setting.

  And the two of them, side by side, looked down on a scene of horror.

  * * * *

  The medusae were being shepherded into a long line that stretched across the air. The lead medusa, itself two kilometres wide, faced an open cage that was even larger than she was, with a gaping, open mouth. Small flyers darted rapidly around the animal, flaring fusion fire, and attacking the medusa with what looked like small darts.

  Trayne pointed. “Look at that scar on her side.” It was a crater of scorched flesh, metres
wide.

  “They’re goading her,” Falcon said, disbelieving. “Forcing her into that cage, with the darts, the plasma jets. And the tight turns those torch flyers are making—they can’t be piloted by humans, not even Earthborn, let alone Martian. Machines, then. Martians and Machines, cooperating in this operation. But what are they doing?”

  Now the medusa was entering the cage, pushing inside gingerly, gently, like a great liner coming into dock, Falcon thought briefly.

  But there was nothing welcoming about this harbour. As soon as the medusa was fully in the cage, a barrage of small missiles was fired into her carcass, from above, below, into the flanks—a sudden, shocking assault. The medusa seemed to become rigid almost immediately: the natural pulsing of her body as she swam, the synchronised waving of her inverted forest of tentacles, all of it was stilled. Now lines shot out of the cage structure towards her, and grappling hooks raked her flesh. From this point, Falcon saw, she would be dragged through the cage, rather than swim of her own volition.

  And then the real work began.

  On the underside of the medusa, lasers spat hard light, the beams easily visible in the murky Jovian air, and crude mechanical blades whirred. These weapons scythed through the graceful forest of tentacles, which drifted away from the main body to be caught in tremendous nets below the cage. Brownish fluid leaked from the medusa.

  Next, more lasers and knives, some of them huge, sliced through the beast’s skin, followed by claws that dragged away the fine, leathery substance in great sheets. Falcon watched with an almost distant curiosity as the animal’s flotation bladders were exposed, great cells of hydrogen and helium, almost like those contained within the envelope of his own Ra. He knew something of the internal anatomy of a medusa; the beasts had been studied by zoologists using sonar, radar, and other non-intrusive probes. He had never seen one dissected before. Of course the gas cells were fragile, only as strong as they needed to be—for all its bulk, medusae were evolved for lightness. The cells popped easily at the touch of the lasers, collapsing into wispy folds that were briskly snipped away.