by Paul Preuss
Inside the capsule, the passengers lay smothered under ten gravities of acceleration. A row of diodes on their control panel showed all green, but they would have been all green even in a dire emergency; the little green lights were window-dressing, intended to reassure passengers who were utterly helpless to affect their fate.
On the videoplate, the perfect prerecorded launch proceeded. The capsule silently accelerated at a hundred meters more per second each second that ticked away, until it was moving far faster than a high-powered rifle bullet.
The coils of the launcher smeared into invisibility. Only the longitudinal rail that supported the coils could be seen, a single impossibly straight ribbon of shining metal vanishing somewhere above the distant horizon, into the stars.
They were weightless.
“Acceleration is complete,” the voice of the capsule reassured them. “Only five more seconds until our launch sequence is over. Just continue to relax.”
Along the final few kilometers of the electric raceway the capsule drifted weightless at blurring speed, subjected to fine magnetic adjustments in aim and velocity—here each individual capsule had its trajectory tailored to fit its particular destination, whether near-Ganymede parking orbit or distant moonscape fly-by.
Meanwhile the frozen surface of Ganymede curved away beneath the track, which in order to maintain its artificial Euclidian straightness now rose above the ice on spindly struts.
In an eyeblink it was over; the long launcher rail was behind them, and the ice mountains of Ganymede were falling rapidly away. The screen was filled with stars.
“All right with you?” said Mays, not really asking her permission, as he tapped the channel over to “Itinerary.”
On the wide screen the scale of the graphic was set so as to fill the plate with the icy disk of Ganymede; a pale green line parallel to the equator extended from the far right side upward, and along it a bright blue line crept imperceptibly. The green line was their planned route; the blue line was their actual track, as monitored by ground-based radar and navigation satellites. The two lines currently followed an identical trajectory for as far as they extended, and unless something went terribly wrong, they would stay that way throughout the trip.
Mays adjusted the scale. The disk of Ganymede zoomed down to a tiny speck in the lower right portion of a screen filled with stars. The larger disk of Jupiter, realistically patterned with cloud bands, now dominated the center of the screen. Arranged around it in concentric rings were the orbits of Amalthea, Io, Europa, and Ganymede itself. Callisto lay farther out, offscreen. It was the poor sister of the Galilean moons, thought to be too like Ganymede to be worth a special trip; only when the moons were arranged so that the laws of celestial mechanics decreed it easier and quicker for a capsule to fly past Callisto than not were tourists able to judge Callisto’s charms for themselves.
The pale green line was a graceful loop of string that swooped inward past Io, curved steeply around Jupiter, came near Europa on its way back, and finally rejoined the orbit of Ganymede a third of the way farther along in its circuit. Amalthea was not on the itinerary; its orbit lay well inside the capsule’s closest approach to Jupiter.
Given the capsule’s energetic initial acceleration from Ganymede, most of the ride was coasting. But at certain key junctions, a nudge from the capsule’s strap-on rocket was necessary to get the roller coaster all the way around the curve.
Mays contemplated the graphics on the video plate, which at this scale changed too slowly to be perceived. The orange light of the false Jupiter was reflected in the face-plate of his spacesuit and lit a warm gleam in his eye.
Marianne yawned. “Maybe I’ll take the sleeper. Wake me when we get to Io.”
His reply was unnaturally delayed. “Delighted, my dear,” he murmured at last.
Something in the tone of his voice attracted her glance. “What are you scheming, Randolph?” she asked lazily, but the hypnotic was already running in her bloodstream, and she could not stay awake to hear his answer—
—which at any rate he did not give.
15
The columns of white vapor that blew out of the crevices in the ice gave an illusion of great force, but there was nothing to them, only widely spaced water molecules moving at great velocity under virtually no pressure. These most tenuous of winds had blown the huge alien antennas clear off into space; as the ice had dissolved from beneath their roots, the massive structures had drifted free and wafted away as lightly as if they’d been dandelion seeds on a summer breeze. With them went the secret of their communication with the stars—and with the core of their own moon.
Blake and Forster lay side by side in the Europan sub, Blake in the command pilot’s couch, skimming across the lacy ice. Hawkins and McNeil guided the sub by the tips of its wings. The pearly mist was so thick that light from their helmet lamps bounced back into their faces from a meter or two away.
Without a thread to guide them, they could have floundered for hours; they had to feel their way to the entrance shaft along the communications cables that hung like garlands in the mist. They found the opening of the shaft, a wider artificial blowhole in the featureless fog and ice, and the Old Mole tethered nearby, stationed there in case the shaft needed re-opening against the tendency of the boiling water down below to freeze over again.
“We’re ready to go in,” Blake said over the commlink.
“All right, then,” came back Walsh’s voice.
The launch was pure simplicity. Blake curled the submarine’s flexible wings around its body until the craft was smaller than the diameter of the shaft in the ice. Hawkins and McNeil positioned it above the opening and gently shoved it into the pressureless blowhole with the force of their suit-maneuvering systems.
The sub dived blind into the impenetrable fog. A hundred meters down, the surface of the water came up suddenly, a vigorously boiling surface over which a steaming skin of ice constantly froze and broke apart and reformed.
Triggered by radar to ignite upon impact, the submarine’s rockets fired a brief burst to drive the buoyant craft below the surface that otherwise would have rejected it. The rockets continued firing, blowing out a stream of super-hot bubbles, until the free-swimming craft’s wings could unfurl and grab water. With strong strokes, the submarine swam swiftly down into the deep. Then it turned on its back and sought the undersurface of the ice. The water was murky with life—swarming, concentrated life.
“Hungry little devils.” Forster laughed, the happiest sound he’d made in months. “They’re exactly like krill. Swarms and swarms of them.” His bright eye had fixed upon one among the myriad swarming creatures fumbling against the polyglas, and he followed it closely as it wriggled helplessly for a moment before orienting itself and darting away.
“Are they feeding?” Walsh’s voice came to them over the sonarlink.
“Yes, most of them,” Blake answered. “They’re feeding on the underside of the ice, on mats of purple stuff. An Earth biologist would call it algae … maybe we should call it exo-algae. And miniature medusas, clouds of them, are feeding on them.”
“We’ll have to let the exo-biologists sort it all out,” Forster said. “I’ll get a few samples, Blake. But don’t let me take too long about it.”
“If you didn’t know we were inside one of Jupiter’s moons,” Blake said into the comm, “you’d think we were in the Arctic Ocean. And that it’s springtime.”
Forster and Blake were lying prone in the Europan submarine, nominally a two-person craft with just enough room for a third occupant to squeeze into the passage behind them. The Manta, they had nicknamed it, on the principle that if an old ice mole deserved a name, so did an old submarine—doing what the Old Mole couldn’t do, for the ice miner had served its main purpose as soon as it had cut its way into Amalthea’s interior.
The Manta was swimming upside down with respect to Amalthea’s center, its ventral surfaces skimming along only a meter from the rind of ice. The teeming
biota of Amalthea’s “arctic” seas—or at least a good and lively sample of it—was spread before them, brightly illuminated by the sub’s spotlights, separated from them only by the thin clear polyglas of the sub’s bubble. The white light was quickly diffused in water so thick with living particles—all of them eating or being eaten—that it resembled a thin broth. The darting, teeming schools of transparent krill were a shifting veil of rainbows in the beams of the floodlights.
The men in the sub used magnifying optics to examine the creatures on something closer to their own scale. The medusas were like many of the myriad species of jellyfish that swarm through all the seas of Earth, pulsing with strips of colored light. The creatures Forster called “krill” were shrimp-like, multi-legged little beings with flat tails and hard transparent shells which left their pulsing circulatory systems visible. Whenever the submarine’s lights were directed toward them they swam frantically away—behavior that was easy enough to understand, given that a boiling “sun” was visible as a hot point of light many kilometers down in the murky depths and that the foodstuff of the krill lay in the opposite direction.
“What was that?” Blake said suddenly.
“Ventris, we have new visitors,” said Forster. “Something bigger than anything we’ve seen yet.”
“Looked like a squid,” said Blake. “There’s another … a bunch of them. I’m rolling the Manta.”
The submarine flapped its wings and made a lazy half roll in the soupy water. The dark waters came alive with flickering, glowing life. Uncountable multi-tentacled, torpedo-shaped creatures danced in synchrony beneath them, none of them bigger than a human hand, but packed together in an immense school that darted and turned like a single organism. Each translucent, silvery animal was bright with turquoise beads of bioluminescence; together they formed a blue banner in the dark.
“They’re diving again,” Blake said.
“We’ll follow them, Ventris,” Forster said into the sonarlink. “I’ll worry about specimens later.”
Blake pushed the Manta’s diving controls forward and the sub put its transparent nose down. Flexible wings rippled, driving the craft deeper into darkness.
The Manta was a well-used sub, not as old as the Old Mole but based on vintage technology. Its passengers rested in an Earth-normal pressure regime of mixed oxygen and nitrogen. The sub carried liquid nitrogen in pressurized tanks and got its oxygen from the water, but while its oxygen-exchange mechanisms—its “gills”—were efficient enough at constant depths, the craft needed time to adjust internal working pressures to constantly changing external pressures.
And the pressures on little Amalthea, while they didn’t change as rapidly as they did on big Europa (or on bigger Earth), nevertheless mounted swiftly toward impressive numbers. At the surface, a person in a spacesuit weighed a gram or two, and the pressure was zero, a near-perfect vacuum. At the moon’s core the same person would weigh nothing at all—but the pressure of the overlying column of water would have increased to several hundred thousand kilograms per square centimeter.
Blake, frustrated, couldn’t keep up with the rapidly descending school of exo-squid. The Manta’s alarm hooter went off before he’d descended four kilometers: Do not attempt to exceed the present depth until the gill manifold has been recharged, the sub’s pleasant but firm robot voice instructed him.
Blake let the Manta level itself. They could do nothing but wait while the artificial enzyme mixture in the sub’s gill manifold was enriched. Outside the craft swam a menagerie of weird creatures, resembling several new species of luridly colored medusas and jellyfish and glassy ctenophores. A fish with a mouth bigger than its stomach drifted past, peering hungrily in at them with eyes as big as golf balls.
“They’re coming back,” Forster said.
“Sir?” Blake was paying attention to the instruments, not to the view through the bubble.
“Unfortunately we have a poor image up here,” said Walsh on the sonarlink. “Can you tell us what you are observing?”
“The squid. It’s almost as if they’re waiting for us,” Forster said. “The way they dance, you’d think they were laughing at us.”
“That’s your mood talking, sir,” said Blake, smiling.
“Perhaps we’re thinking alike.”
Blake gave the professor a strange look. “You and them?”
Forster didn’t elaborate.
Blake watched the rippling sheet of blue light half a kilometer below them, undulating as if in a lazy current, a sheet made of a thousand little vector-arrows, a thousand tentacled projectiles.
You may proceed to depth, said the sub’s voice, and a tone sounded, indicating it was safe to descend. Blake pushed the controls forward. Instantly the school of fiery creatures peeled away, diving toward the bright nebulosity that lay at Amalthea’s center.
The water was less clouded with nutrients here, but hazy with rising bubbles. The Manta was diving against a lazy upward flow of bubbles.
“Outside temperature’s going up fast,” Blake said.
The core object, though still at a great distance, was more than a blur of light; it was a pulsing white sphere, too bright to look upon directly, a miniature sun in watery black space.
The hooter sounded again. The pressure was approaching a tonne per square centimeter. Do not attempt to exceed the present depth until…
“Yeah, yeah,” Blake grumbled, taking his hands away from the controls. They waited longer this time, while the oxygen from the sub’s gills dissolved in the large volume of fluid in its circulatory system.
“I say, they’re doing it again,” Forster exclaimed. Again the school of squid appeared to be waiting for them, wheeling and darting at a constant depth almost a kilometer below. Forster’s voice was as excited as a boy’s. “Do you think they’re trying to communicate?”
“Not much sign of that,” said Blake, playing the skeptic.
You may proceed to depth, said the sub. The tone sounded, and they dived.
The water around them was thick with bubbles now, microscopic spheres streaming past in the millions, and big wobbling spheroids that looked alive. The school of squid swam away below, sliding off to the right as it dived.
“Those bubbles are hot,” said Blake.
“They’re full of steam,” the professor said. “Rising in columns. The squid are avoiding this one—we’d better do the same before our gills cook.”
The Manta flapped its wide wings and slid off to the right, following the invisible wake of the glowing squid. Suddenly they were in still, cool water.
Beneath them, the hot core had grown to the apparent size of the sun seen from Earth—too bright to look at directly, without the viewport adjusted to filter the light. Streams of bright bubbles were flowing slowly away from Amalthea’s white core in serpentine columns, radiating symmetrically away from the region of maximum pressure, reaching steadily upward in every direction toward the moon’s surface.
“I’ll bet there’s a geyser at the top of every one of those,” said Blake.
“Bet not taken,” said the professor, who had noted the regular geometry of the bubble streams. “I’d say you’re right.”
Amber lights glowed on the panel beneath the spherical window. In a reasonable voice the sub said, Please exercise caution. You are approaching the absolute pressure limit.
The inner polyglas hull of the Manta, in which they rode in comfortable Earth-normal conditions, was nearing the point where it would implode from the crushing pressure of the water.
“This is about as close as we’re going to get,” said Blake.
“We’ll break off now,” Forster ordered. “We’ll get what we can in the way of images. On the way up, stop long enough to let me take water samples every five hundred meters.”
“Right,” said Blake. His hands flexed on the controls—
—but the professor reached to touch him, his dry fingers lying gently on Blake’s, commanding him to be still. “A moment more. Just a m
oment.”
Blake waited patiently, trying to imagine what was going through Forster’s mind. The professor had come tantalizingly near the object of his decades-long search, but still it kept its distance, if only for a little while longer.
Forster listened to the sounds that came through the hull, broadcast on the sub’s sonar: the squeaky fizz of billions of pinpoint bubbles boiling off the hot core, the liquid slither and plash of bigger bubbles colliding and joining together. Almost overwhelming these inanimate sounds were the skirring and chittering of masses of animal life in this spaceborne aquarium, this vast dark globe of water rich in the nutrients of a terrestrial planet’s oceans.
There were patterns in the cries of life, mindless patterns of busy noise that marked feeding and migration and reproduction—and bolder patterns as well?
The school of squid still waited below, swirling and diving and soaring and darting; the thousand wriggling creatures sang as they swam, in rhythmic birdlike chorus. Beneath the soprano choir a deep bass boomed with studied deliberation, like the slow ringing of a temple bell in the tropical night.
As Forster listened, he imagined that he knew what the booming was … that the core itself was calling him.
16
Here it came: a hemisphere bulging with mountains of orange sulfur, flooded with red sulfur lava, wind-swept with yellow sulfur dust, pitted with burned black sulfur cinders, drifted with white sulfur frost…
The first humans to see Io, in reconstructed video data sent back by Voyager 1, had called it a “pizza pie.” What would it have been called if those first observers had lived not on the outskirts of Los Angeles but in Moscow or Sao Paolo or Delhi?
Or seen it as Randolph Mays and Marianne Mitchell were seeing it now…? The videoplate of their tin can capsule showed the fast-approaching moon in real time, at the same angular spread as if they’d been looking out the hatch with their own eyes. Io did not look much like a pizza pie to Marianne. It looked like hell frozen over; not counting the insides of various spaceships, it was the ugliest thing she had seen in her travels yet. But Io’s ugliness was so bold and wild, its elemental forces so immodestly displayed, that she found it almost arousing.
