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 . . .”