Noise - Hardcover

Hal Clement lives in Milton, Massachusetts.

1
 
OVERTURE
 
 
Poetically and almost literally, Kainui's mantle is at endless war with its overlying ocean. Perhaps they are simply too intimate; they confront each other directly, with no identifiable intervening crust. The underside of the interface is not quite liquid most of the time; the upper is technically gas, since the ocean at that depth is far above water's critical temperature.
What pass for tectonic plates, from township to county size, are solid enough to crack and tilt and be carried as individual units by mantle convection. Tsunamis are generated constantly, sometimes by abrupt plate shifts--quakes--sometimes by vulcanism, though there is nothing at all like a Terrestrial volcano on the world.
When magma emerges from the mantle to become lava and meets the sea there is of course violence, but Kainui has never experienced a Krakatoa-type steam blast. The weight of twenty-eight hundred kilometers of water, nearly all of it far saltier than any Earth ocean, provides some eighty thousand atmospheres of pressure. A few hundred kelvins rise in temperature has no real effect on either phase or volume.
So when, one day, a tenth of a cubic kilometer of glowing liquid silicate was suddenly exposed to ocean bottom along the line between two spreading plates, the result was merely a linear-source sound wave.
Its front spread out as wave fronts do, trying to become flatter and flatter as it left its source behind. It failed miserably. It passed through layers of differing salinity, temperature, and tonnage of suspended matter. Sometimes locally it turned concave and was focused so narrowly as almost to regain its original pressure. Sometimes it diverged, but its total energy degraded only gradually toward heat.
Nearly an hour later, when parts of it were nearing the ocean surface, that energy had been distributed over much of the planet, but there were still local, focused, high-pressure regions. Now the background pressure was getting low enough to let the water molecules move noticeably with the front.
When it actually reached the next real interface, between ocean and atmosphere, the water--long since actually liquid--was able to rise, and a tsunami was born. Most of it was imperceptible to human senses, since it covered a large area and had no coast to overwhelm; but even in the last few kilometers there had been some local refraction. In several places smaller microtsunamis originated, and Mike Hoani was very aware of one of these.
Its bulge was three or four hundred meters across and perhaps twenty above the general sea level, but this was not itself an easily spotted reference. The Malolo's upward acceleration was only barely noticeable to anyone on board, but her tilt was another matter.
Mike had been trying to get his sea legs for two days now, since his first and last real view of a local tsunami. That had been during launch, when either the arm supporting the dock had been swinging downward or Muamoku had been rising. Cities were massive enough to respond rather slowly to changes in ambient pressure. The ship was different.
Ocean swells, on the rare occasions that they were the only disturbances present, Mike could usually handle; if they were too long--waved to see, they were, under Kainui's one-third Earth gravity, too slow to be a problem. The sometimes strangely shaped and always unpredictable microtsunamis, analogous to the streaks of light focused on the bottom of a washbasin when the water is stirred, were quite another matter; he didn't merely lose his footing, he was often thrown from it.
The catamaran's deck was railed in many places and rigged with safety lines in most of the rest, but not continuously or everywhere; the need to dive overboard or climb back was random in both time and place. It was wet, since there was enough wind to break wave tops and provide spray. It was slippery. This time Mike slid.
He was not hurt, being encased in sound armor fifteen centimeters thick except near joints, but he was frightened. Surprising both himself and the witnesses, however, he did the right thing. He swung the helmet hinged between his shoulders forward over his head, latched it, and then grasped at a passing line. He managed to catch this and stop his slide before actually going overboard. The deck was still rocking, and without shame he crawled away from its edge before trying to regain his feet.
Even the child at the masthead was watching him, lookout duty ignored for the moment, and the three native faces showed expressions of approval around their breathing masks. Maybe all four, counting Mike himself, were thinking that this Hoani fellow mightn't be too much of a burden after all, but nobody said anything. Especially Mike. He just stood up, carefully.
A mere day later, that particular wave had long gone to warm the surface water and the air above it. Mike's reflexes had improved even in that time, and he had some attention to spare now when the lookout's shrill voice sounded from above. It was hard to distinguish words over the endless thunder, but he followed them fairly well.
"I'a'uri! One hand, port bow, half a kilo, past ripe!" The captain's response was a wave, and Keokolo at the tiller simply changed heading. The breathing leaf had not yet been deployed that morning, and steering was straightforward. Mike, guided by the child's words, made out a dark-colored patch of what might have been seaweed in the indicated direction. It seemed more than a hundred meters across. He assumed it was a sample of the pseudolife they had come to harvest, but it meant nothing specific to him until after Malolo had been brought to at its edge.
Even then he could make out no real details, except that the weed seemed to be growing on something clear suspended a meter or so under the surface.
At that point both adult crew members expressed approval of 'Ao's judgment. She had descended from the mast without orders and was waiting with just a faint expression of anxiety visible around her mask. The passenger, who had a youngster of his own on Earth, could interpret this; the child had been afraid of being wrong. She relaxed visibly at the captain's words.
Mike Hoani couldn't quite decide whether he should be surprised or not. None of the crew had seemed to be, and it was reasonable that the youngster would be the first to spot the i'a'uri, whatever that was, since she spent much of her waking time at the masthead; but like Mike she was on her first sortie. Unlike him, she was barely forty years old and still carried her doll even on duty.
Her ability not only to identify the i'a'uri but to give details seemed to say more about Kainuian education than Mike had guessed so far. Apparently her instructors had more or less outgrown the notion that experience is the best teacher even though she had been sent to sea while still a child.
That was a point to be noted; it might possibly fit in with the convergent-evolution language thesis he was hoping to complete while on the planet. Different floating cities had been built by colonists from different Polynesian islands, but generations of trade among them had gradually caused a blending of tongues that was still far from complete.
Nothing much else had seemed surprising, either, during the time they had now been sailing. The weather had been fine; there had seldom been more than a dozen of the world's immensely tall thunderheads in view at any one time, though of course the ubiquitous ionized haze hid such things long before one's line of sight reached the distant horizon. The thermals had not forced Malolo to change her basically northward course; they were routine. Even little 'Ao had needed no verbal orders; she obeyed a simple gesture from the captain whenever the ship had driven into the hail column under one of them, darting over to the collecting sheet and standing by to sweep the hailstones either into the drinking and bathing breakers before they melted and absorbed too much carbon dioxide or, if there was too much of the material, overside.
Only one other vessel had been seen during that time. Wanaka, Malolo's captain, had logged--and reported to the others with some amusement, as though they couldn't see for themselves--that it bore the same name as their own craft, but was a single-hulled double-outrigger of about twice their own tonnage flying the flag of Fou Savai'i and, like themselves, the "nothing to trade yet" pennant. Both adults seemed a little surprised that it was sailing at search speed; their own craft at the moment had its kumu'rau deployed, since the suns were high and it was rare for any craft to miss an opportunity to top off on oxygen. This of course could not be done at night, and at least some of each day had to be spent searching for metal.
The name went into Mike's mental notebook, too. Malolo meant "flying fish" in more than one classical Polynesian language--on a planet that had no native bacteria, much less vertebrates, as far as anyone had been able to find out.
The thing 'Ao had just seen and identified had been visible enough at half a kilometer, of course. The weather was unchanged, with Kaihapa barely visible through the haze, hanging high in the western sky and the suns nearly at the meridian. There was enough wind to move the ship at a reasonable clip, but not enough to break the swells; and by now, with his improving reflexes, the seismic bumps and hollows in the ocean surface were becoming merely a minor background nuisance to the passenger. They caused the top of the mast to swerve and jiggle in a way that made him avoid watching it, but 'Ao typically held on without apparent trouble and with her doll clinging to her shoulder, neither showing any sign of being bothered.
Malolo was now hove to at the edge of twenty thousand or so square meters of rippling jelly floating just under the surface. Wanaka, the vessel's owner and captain, was still aboard to make sure it stayed there. 'Ao, Mike, and Keokolo had flipped their helmets on and gone overboard to harvest.
The first two were connected by a safety line, since the visitor knew practically nothing of Kainui hand language, and vocal communication would have been hopeless below the surface even if helmets had been unnecessary. Noise from the ocean bottom was continuous, and deafening, and often deadly in overpressure. Mike had been told firmly to stay with the child, as though the connecting rope allowed anything else. He watched her carefully. He already knew why she avoided the nearly black leaves, which spread just at the surface and shadowed more than half the slimy stuff underneath, but he had been told practically nothing about the actual mechanics of harvesting. The items they wanted, he did know, were in the sheet of jelly itself, whose upper surface oscillated vertically under the push of the endless random microtsunamis and more regular swells, varying from half a meter to something like two and a half below that of the even more violently rippling water. Sometimes Mike found himself wading unsteadily on jelly, sometimes swimming. The meter-and-a-quarter-tall child always had to swim.
It seemed simple enough. 'Ao's thinly gloved hands groped over the jelly and every few moments found a slit not visible to the man. Reaching a few centimeters into this she would feel around briefly and pull the hand back either empty or grasping a black purselike object ten or twelve centimeters long that reminded Mike of a shark's egg case. This she would deposit in a circular basket being towed behind her, and resume groping. 'Oloa, the doll, clung to her shoulder still, but 'Ao paid no attention to it; she was working.
Keokolo seemed to be doing the same thing, except that the objects he gathered were clear and glassy in appearance, and the container in which he placed them, unlike the girl's, seemed to need no floats. Periodically one of the harvesters would return to Malolo and hand the collecting basket up to the captain, who transferred its contents quickly to something Mike couldn't see, since the salt-stained gunwale was more than a meter above him. Wanaka would then return the bucket to the harvester.
It was a long, rather boring, and tiring process. The noise armor was heavy and much less flexible than Mike would have liked, and the harvesters seemed to be taking a completely random course over the i'a'uri's surface; the visitor could not even guess how nearly finished they might be. They stopped and ate for three-quarters of an hour while Kaihapa eclipsed the suns, then resumed work until the latter set. Mike had tried to calculate how many of the items being collected there might be on the vast surface of the pseudoorganism, and suspected Malolo might be there for several days; but when he suggested this aloud, the captain shook her now-exposed head negatively.
"No," she said through her breathing mask, rather regretfully he thought. "If we'd come across it sooner we might have been able to get a full load, but as 'Ao said when she spotted it, this one is quite a bit past ripe. Its batteries are nearly full, and there's no way to keep it from sinking out of reach after the leaves are gone. It's a rather old design, though a very efficient collector. Its iron is very pure and its water drinkable. It's too bad to see so much of it get away, though of course having only one cargo item to trade isn't good policy anyway."
Mike figuratively kicked himself for not having figured out that the pseudoorganism's name probably came from a blend of a Samoan word for "fish" and a Tahitian one for "iron," and added several notes to his mental collection.
"D'you think we should split it, or let it die?" asked Keokolo.
"Oh, split it. It's still a useful type, and if it ever can't compete with newer stuff the problem will take care of itself," answered his wife. "We have about a third of what I want, and should get the rest before sunset tomorrow. When we do, you can show 'Ao and Mike how to divide it without depowering one of the halves."
"I already know about that!" the child cut in.
"Your badge doesn't say so, but you can show Keo if you want. We'll be glad to upgrade you."
Mike had a pretty good idea of what they were talking about. 'Ao was not the child of the adult crew members, though they were married and had a daughter in Muamoku. No children of the same Kainui family ever sortied on the same vessel with their parents or usually even at the same time, but children started their practical education early. 'Ao was not quite forty, nearly ten in Mike's years. Family separation was a custom retained from their Terrestrial ancestors, who had placed high importance on the preservation of family lines. 'Ao's parents and small brother were not afloat just now and none, except the brother, was likely to embark until she herself had either come home or been away long enough to justify assuming that she had been lost at sea or adopted by another city.
Mike said nothing; he listened, fitting what he heard into his increasingly detailed mental picture of the colony world's society and, most particularly, its pattern of languages. By ancestry he was himself as pure Maori as Earth could now provide. By training he was a historian and philologist, and ...