The Medusa Chronicles

by Stephen Baxter

  That optimistic mood didn’t last long.

  When the operation had been approved the extraction plants were meant to be fully automated: in other words, crewed solely by Machines, under the control of WG staff stationed on the moons of Jupiter. But with time, the Machines had shown increasing signs of independence. Disturbed, and ever mindful of the KBO flinger disaster, the WG brought in a Martian crew to supplement the Machines, and to keep an eye on them—only to find, a few years later, the Martians themselves becoming increasingly independent-minded, increasingly difficult to manage and, Earth suspected, exploring options of their own on Jupiter. Options which had nothing at all to do with mining helium for the home worlds.

  Eventually the Martians themselves came up with a plan to rectify this growing atmosphere of distrust: to include the Machines as equal partners in a daring enterprise that required human expertise and Machine resilience together. It would be a cooperative venture, a political stunt—and also a grand and highly visible project that could not be achieved by either alone.

  A journey to the centre of Jupiter.

  The WG could hardly veto the project. But it needed somebody of its own on the inside. Somebody with historic connections to both Jupiter and the Machines. Somebody, ideally, seen as somewhat neutral and detached from all the worlds of mankind. A citizen of the WG equipped to survive the conditions of Jupiter.

  Who else?

  So Howard Falcon was summoned from his patient exploration of Jupiter’s exotic outer regions, a study that had occupied contented decades. Of course he was drawn by the prospect of a mission to the Jovian core, for the dream of descending deeper than the highest clouds had nagged at him for most of his long life. Getting elbow-deep in the murk of inter­planetary politics seemed a small price to pay to achieve that dream.

  And so here was Howard Falcon with a Martian on his bridge.

  20

  The pressurised cabin was a sphere cut in two by an open mesh deck, living space and control area above, stores and systems below. Trayne’s armour-like exoskeletal support suit whirred and hissed as he moved through this space, and Falcon knew that he was supported by more subtle systems embedded within his body, from pumps and motors to assist his heart and lungs down to molecular-level restructurings of his organs, muscles, bone and cartilage.

  All this to enable him to withstand Jupiter’s ferocious gravity—two and a half times that of Earth, and around seven times that of Mars. It was an irony that Martians had been able to rebuild themselves to work in the Jovian environment where Earthborn humans, born in a tougher gravity, generally failed—but then for centuries Martians had needed technological support just to survive visits to Earth, and had learned to cope. Even so, the Ra’s savage descent into Jupiter had put those systems under unprecedented strain, and Falcon hoped to prove that Martians still needed the experience and skills of an Earthborn such as himself to support their bold venture.

  Still, he wished no harm on anybody, and certainly not on this high-­spirited if exasperating young Martian volunteer.

  His mobility routine finished, Trayne sat down on a roomy couch, hooked his suit up to various support systems, and “ingested nutrients non-intravenously,” as his medical checklist demanded: he ate a bagel and sipped black coffee. Stiff supports at his neck and back made his movements awkward. “So I was out for days.” He sounded indignant now. “I missed all of the mission so far—the last stages of entry, inflating the ­dirigible—”

  “Don’t blame me. I argued with your medics, who wanted to abort altogether and bring you straight back to Amalthea.”

  Trayne looked chastened. “All right. Well, I’m glad you let me get this far.” He glanced around at the cabin. The walls were cluttered with instrument and control panels, save for a few windows set to ­transparency—and beyond those windows, salmon-pink shadows shifted. Trayne grinned. “Wow. I feel like I’m slowly waking up. That’s Jupiter out there. I really am aboard the Ra.”

  “You really are.”

  “I guess for you it’s just like being back aboard the Kon-Tiki.”

  “Not particularly,” Falcon said dryly. “That dive was the best part of two centuries ago, you know. Ra features rather a lot of upgrades . . .”

  If Kon-Tiki had been Falcon’s Apollo, a one-shot pioneering vessel, the Ra was his Ares, the class of vessel John Young had taken to Mars, designed from the beginning for extended exploration. Ra had, among other enhancements, a buoyancy envelope consisting of a shell of self-healing polymer surrounding a structure of aerogel, “frozen smoke,” much more robust than the Konicki’s air bag. The gondola, doubling as a shuttle to orbit, was powered by the latest deuterium-helium-3 fusor technology and was significantly more capable than his old craft’s deuterium-­tritium equivalent. All these elements had been tested out over the years in a number of challenging missions.

  “I know I’m a relic of a bygone age. But at least now they call me the Santos-Dumont of Jupiter, as opposed to the Montgolfier.”

  “Who . . . ?”

  “Never mind.”

  “I was always a fan of yours, you know.”

  “A fan?”

  “I mean, the flight of the Kon-Tiki wasn’t exactly Greenberg on Mercury, but it was still pretty impressive.”

  “Praise indeed.”

  “And now here I am, flying in the clouds of Jupiter.”

  “Here you are.”

  Geoff Webster had always said Falcon was basically a showman. Falcon remembered that quote his old friend had been so fond of: ASTONISH ME! Now, unable to resist a little of that spirit, Falcon clapped his artificial hands.

  The cabin walls turned entirely transparent.

  Trayne’s eyes widened.

  It was as if the two of them, with a clutter of equipment, were suspended in a tremendous sky, with the huge hull of Ra over their heads. Below was an ocean of cloud, pale and billowing, which stretched almost unbroken to a flat horizon. In that ocean lightning flashes swarmed and spread—electric storms, Falcon knew, the size of continents on Earth. They were looking to the west, where the setting sun—five times further away from Jupiter than from Earth—cast shadows hundreds of kilo­metres long. Above them were more cloud layers, filmy, cirrus-like sheets and streaks, obscuring a crimson-black sky in which a handful of brilliant stars could be seen to shine.

  “It’s almost like Earth,” Trayne murmured. “On one of that mud bath’s better days.”

  “Remember the briefings? We’re about a hundred kilometres beneath the top of the atmosphere—which these days is defined as the point where the air pressure is one tenth of Earth’s. We used to use an apparent surface a few hundred kilometres below this level as a reference, but that turned out to be little more than an artefact of sensor reflection, and too unreliable to be useful. We’re just above the cloud deck the climatologists label the C layer.”

  Trayne nodded, and pointed up. “A is ammonia cirrus, fifty or sixty kilometres higher up. Below that, B is ammonia salts—”

  “And C is water vapour. Out there the conditions are like a shallow sea on Earth, which is why the local life is so rich—”

  Trayne pointed to a darkish smear, off to the left, the south. “And what’s that?”

  Falcon eyed him. For the Earthborn passengers Falcon had brought this way over the years, starting with Geoff Webster and Carl Brenner and other veterans of that first descent in the Kon-Tiki, the trigger word “life” usually provoked a storm of questions. But not with this young Martian.

  “That,” Falcon said heavily, “is the Great Red Spot.”

  Trayne did a double-take. “Wow!”

  “You’re seeing it edge-on. It’s a persistent storm—hundreds of years old, at least—but it’s actually very shallow.”

  “Is it safe?”

  “For us? Oh, yes—we’re thousands of kilometres away. We’re more likely to be t
roubled by an eruption from one of the big, deep Sources.”

  “The Sources—the origins of the big radio outbursts? I’d like to see that. The Wheels of Zeus!”

  Falcon grunted. The “Wheels” were a spectacular but harmless phe­nomenon, tremendous bands of bioluminescent light in the air triggered by the shock of distant, tremendously powerful radio outbursts. Falcon was still embarrassed he had been alarmed when confronted with them in the Kon-Tiki. “Tourist-brochure codswallop.”

  “Why are we so close to the Spot? I read that you took the Kon-Tiki down far away from that feature.”

  “There was so little we understood before I made that first descent. In particular, we didn’t know that storms like the Spot dig up nutrients from the layers below, all the way down to the thermalisation boundary. They’re like ocean springs on Earth.”

  “So the Spot attracts life?”

  Falcon grinned. “Exactly. Life like that.” He pointed over Trayne’s shoulder.

  And Trayne turned to see, on the other side of the ship, a forest of ten­tacles waving like seaweed—it seemed just beyond the cabin wall.

  “Citizen Third Grade Springer, I’d like you to meet Ceto.”

  21

  Falcon, at the controls, let the Ra drift away from the great medusa and down into the water-ice clouds. Soon the layered sky above was obscured, but they glimpsed still deeper cloudscapes below. A kind of snow fell around the hull now, pinkish flakes that spun in the updraught, and there was a slower, more elusive rain of a variety of complex shapes, kites and tetrahedra and polyhedra and tangles of ribbon. These were living creatures. Falcon knew they could be large in themselves—larger than a human—and yet, in this ocean of air, they were mere plankton: food for the medusae.

  As the dirigible backed off, Ceto became more visible. The Ra was a tremendous craft, its envelope of fusion-heated hydrogen more than eight hundred metres long. But the medusa was more than three times that length, an oval-shaped continent of creamy flesh from which that inverted forest of tentacles dangled, some as thick as oak trunks, Falcon knew, and some so fine they ended in tendrils narrower and more flexible than human fingers. Her coloration mostly matched the background of the pale-pink cloudscape, and even close up her features were oddly elusive: this was camouflage, a protective measure in a sky full of predators. But along her flank was a vivid tiling, a pattern of huge regular shapes in black and white that, if Falcon looked closely, resolved into finer sub-patterns of almost fractal complexity. This was one of Ceto’s voices, her natural radio antenna. The Ra had instruments to hear that voice, and to reply: huge antennas, wires trailing through the Jovian air.

  Trayne Springer seemed stunned. Falcon let him take his own time.

  “Ceto,” Trayne said at last. “Why that name?”

  “The mother of the medusae, in classical mythology. Ceto isn’t literally a mother, but she has given birth. Medusae are a kind of colony creature—so Carl Brenner used to think anyhow; I haven’t followed the academic debates since he died. Certainly I’ve seen her . . . bud. She spins in the air and fragments at the rim, and infant medusae spin off. She’s very vulnerable as she does so, and others of her kind stand guard to draw away the mantas and other predators. It’s quite a sight, a formation of beasts the size of small islands hanging in the air, all working together. And this, this region between cloud layers C and D, is where the medusae live out much of their lives. It’s like a world-spanning sea tens of kilometres deep.”

  Trayne pointed down at a dense, dark cloud layer. “That is D, then.”

  “There are several more layers below that, between here and the ocean boundary. The labelling is controversial, and I’d avoid getting into a discussion about that with the boffins up in Anubis City.”

  “The ‘ocean boundary.’ A transition from gaseous to liquid hydrogen—”

  “A thousand kilometres down, yes. The surface is nothing like as clearly defined as the oceans on Earth—”

  “The pink flakes. Is that snow?”

  “Hydrocarbon foam,” Falcon said. “The sun’s radiation bakes complex organic molecules, which rain down through the air.”

  “Food from the sky. And that’s what the living creatures feed on. Like your pet medusa.”

  “Actually, I think I’m Ceto’s pet . . . And in turn there are predators that hunt down herbivores like the medusae. In a way, the ecology’s structure is similar to the upper layers of Earth’s oceans.”

  “We don’t have oceans on Mars—yet.” Trayne glanced around at the instrumentation panels. “And it’s true,” he said, wonderingly. “I can see the data chattering in. You actually do talk to the medusae.”

  “As best I can. Carl Brenner and I made the first tentative observation of their ‘speech,’ their booming acoustic songs, and their decametre-­wavelength radio transmissions. Their acoustic songs span frequency ranges too great for us to pick up, let alone to retransmit. Whereas the radio signals are accessible through the Ra’s trailing antennas. It’s taken time, and a lot of dialogue, but we have slowly managed to piece together some common concepts.”

  Trayne stared out at the medusa. “But it’s nothing but an immense gas bag. It doesn’t do anything but eat, and breed, and get eaten by mantas. What does it have to talk about?”

  Falcon was irritated, but held his tongue. Sometimes it seemed to him that off-Earth humans, Martians especially, were halfway to Machines in their callous disrespect for any other form of life but their own. That was what came of growing up in a plastic box on a lethal planet, he supposed.

  “She is an individual. As are all medusae. They store shared information in what seems to be a suite of very long, carefully memorised songs. When they die, they are remembered. They are people, Springer. And individu­ally they have long memories. Ceto wasn’t the first medusa I encountered, but she was around long before I showed up. She remembers the Shoemaker-Levy 9 impact.”

  “The what? Oh, the comet that hit Jupiter—”

  “Even before I was born. For the medusae it was close to an extinction event. Many died, communities were scattered . . . They are accepting of death, however. They are intelligent creatures who accept the reality of predation as a kind of toll you have to pay for existence. Their culture is quite unlike ours—but rich nonetheless.”

  Trayne shrugged. “I don’t mean any offence. I’m just a high-gravity guinea pig; my technical speciality is human biomechanics. So what is Ceto saying right now?”

  Falcon turned his mind back to the frustrating conversation that had been curtailed when Trayne woke up. “She’s disturbed by something. A medusa’s image of death is a Great Manta—huge, unstoppable, inescapable. A dark mouth. The Great Manta last came to Jupiter when the comet struck. And now, she says—or sings—the Great Manta is coming again. It’s as if there’s something wrong in her world, something that shouldn’t be here.”

  Trayne stared out, and Falcon wondered if, despite his youth and the coldness of the frontier culture he came from, he was capable of empathy. “Are you saying that that immense animal is . . . ?”

  “Scared?” Falcon let that hang, unanswered. “Anyhow, back to work. We have a checklist to get through before we can return to Ganymede: tests of your piloting and other skills.”

  “Fine with me.” Trayne stood stiffly and made his way to the pilot’s position. “Though I don’t imagine you’re in any rush to get back.”

  “Why’s that?”

  Trayne grinned, almost maliciously. “Hadn’t you heard? Your doctor has come out from Earth and is asking to see you. Oh, and cousin Thera wants a word . . .”

  22

  The balloon wheels of Falcon’s support infrastructure were silent as they ran over the thick carpet of the Galileo Lounge. Clusters of couches and privacy booths divided up the floor space, and he was aware of pretty heads turning to track him as he passed. Celebrity-spotting was a favoure
d pastime here. He resolutely ignored them all.

  And besides, the sky above the clear Plexiglas ceiling was a more spectacular sight than any human or post-human. An annex to a new hotel set just outside Anubis City’s most ancient pressure domes, the Galileo Lounge was already the most famous landmark of this two-hundred-year-old settlement, Ganymede’s largest town. And the lounge’s selling point was that its only light came from the sky: the grand lanterns that were the sun, Jupiter and the inner moons.

  He found Hope Dhoni relaxing on one of a pair of couches. She turned to smile at him as he approached. “I ordered you the usual.” Two glasses sat on the table between the couches.

  Falcon settled beside her and cautiously took a glass, his fingers closing with a click. Iced tea: their once-every-few-decades ritual. “A young Martian warned me you were here.”

  “‘Warned’? Nice to see you too, Howard.” Dhoni watched him, appraising. At first glance he might have thought of her as genuinely young—forty perhaps, no more. But a certain smoothness of her skin, and a peculiar, almost reptilian stillness of her posture, gave away the truth. Like himself, Hope was now over two centuries old.

  “I know what you’re thinking,” she said.

  “You do?”

  “‘Mutton dressed as lamb.’”

  “I bet there’s not many left who remember sayings like that. ‘Mutton’ . . . ?”

  “Oh, it’s probably a setting on a few of the older food synthesis machines.”

  “What I was actually thinking is that you look fine, Hope. For sure it’s better than the alternative, which is a coffin, or—well, a coffin like mine.”

  “You always did have a morbid streak, Howard, and I never liked it. That’s precisely why I insist on seeing you in person, oh, at least every few decades—even though I monitor you constantly, you know that. And before you say it, no, following your glamorous career is not the only thing keeping me alive.”