2312 (32 page)

Prometheus, Pandora, Janus, Epimetheus, and Mimas; these are the moons that shepherd Saturn’s rings.

The rings are only 400 million years old, the result of a passing Kuiper belt ice asteroid being stripped to its core when it passed Saturn too closely.

Mimas, the bull’s-eye moon, is 400 kilometers in diameter, while its crater Herschel is 140. The Herschel impact nearly blew Mimas apart.

Hyperion is a fragment of a similar collision that did blow a moon apart; it is shaped like a hockey puck. The impact caused flash steam explosions across a plane and split the moon as if spalling granite. The facet left behind is pocked like a wasps’ nest by a field of rimless dust-filled craters.

Pandora is shaped like a jelly bean.

Tethys and Dione were both about 1,100 kilometers across (think France), both fractured all over their surfaces, etched by canyons with mile-high walls. Tethys’s Ithaca Chasma is twice as deep and four times as long as the Grand Canyon, and a thousand times older, very battered by Saturn’s everlasting civil wars.

Dione, on the other hand, was disassembled by self-replicating ice cutters in the 2110s, and the Hector-sized segments were then directed downsystem to Venus. They struck Venus on a line parallel to the equator and provided Venus with a deep ocean bed
and the water to fill it, while also knocking a good bit of the choking Venusian atmosphere off into space.

Rhea is as wide as Alaska, with the usual plethora of craters, including fresh ones that throw bright ice rays out from their centers.

Iapetus orbits seventeen degrees out of the plane of Saturn’s equator and thus has one of the best views of the rings; is therefore popular. The bulge is the biggest city in the Saturnian system.

Epimetheus is a misshapen pile of loosely consolidated rubble. It switches orbits with the moon Janus every eight years; they are co-orbital moons, very rare—a sign of past impacts.

Enceladus is covered by braided spills of ice. No craters—the ice surface is too new, as it is continuously resurfaced from the liquid-water ocean in the depths. Heat sources boil some of this carbonized water, creating geysers that shoot many kilometers into space. The water quickly freezes in its flight, and some of it makes it up to the slender E ring; the rest falls back down and under its own weight turns to firn and then back to ice again. A suite of microscopic life-forms was discovered in the Enceladan ocean in the year 2244, and scientific stations have been established on its surface, as well as a cult of votaries who ingest a suite of the alien life-forms, to unknown effect.

There are twenty-six irregular small moons. These are all Kuiper belt objects, captured as they crossed Saturn’s earliest gas envelope. Phoebe, at 220 kilometers across, is the largest of these, and it has a retrograde and highly inclined orbit, twenty-six degrees out of the plane; thus another popular viewing platform.

Titan, by far the largest Saturnian moon, is bigger than Mercury or Pluto. More about Titan later.

One question for computability: is the problem capable of producing a result

If a finite number of steps will produce an answer, it is a problem that can be solved by a Turing machine

Is the universe itself the equivalent of a Turing machine? This is not yet clear

Turing machines can’t always tell when the result has been obtained. No oracle machine is capable of solving its own halting problem

A Turing jump operator assigns to each problem X a successively harder problem, X prime. Setting a Turing machine the problem of making its own Turing jump creates a recursive effect called the Ouroboros

All problems solvable by quantum computers are also solvable by classical computers. Making use of quantum mechanical phenomena only increases speed of operation

two popular physical mechanisms, dots and liquids. Quantum dots are electrons trapped inside a cage of atoms, then excited by
laser beams to superposed positions, then pushed to one state or the other. Quantum liquids (often caffeine molecules because of the many nuclei in them) are magnetically forced to spin all their nuclei in the same spin state; then NMR techniques detect and flip the spins

Decoherence happens at the loss of superposition and the resulting either/or. Before that a quantum calculation performs in parallel every possible value that the register can represent

Using superposition for computation requires avoiding decoherence for as long as possible. This has proved difficult and is still the limiting factor in the size and power of a quantum computer. Various physical and chemical means for building and connecting qubits have increased the number of qubits possible to connect before decoherence collapses the calculation, but

Quantum computers are restricted to calculations that can be performed faster than decoherence occurs in the superposed wave functions. For over a century this restricted time for a quantum computing operation to less than ten seconds

Qubes are room-temperature quantum computers with thirty qubits, the decoherence boundary limit for circuit-connected qubits, combined with a petaflop-speed classical computer to stabilize operations and provide a database. The most powerful qubes are theoretically capable of calculating the movements of all the atoms in the sun and its solar system out to the edge of the solar wind

Qubes are only faster than classical computers when they can exploit quantum parallelism. At multiplication they are no faster. But in factoring there is a difference: to factor a thousand-digit number would take a classical computer ten million billion billion
years (lifetime of universe, 13.7 billion years); using Shor’s algorithm, a qube takes around twenty minutes

Grover’s algorithm means that a yearlong search using a classical computer in a random walk of a billion searches a second would take a qube in its quantum walk 185 searches

Shor’s algorithm, Grover’s algorithm, Perelman’s algorithm, Sikorski’s algorithm, Ngyuen’s algorithm, Wang’s algorithm, Wang’s other algorithm, the Cambridge algorithm, the Livermore algorithm,

entanglement is also susceptible to decoherence. Physical linkage of quantum circuits is necessary to forestall decoherence to useful time frames. Premature or undesired decoherence sets a limit on how powerful qubes can become, but the limit is high

it has proved easier to manipulate superposition than entanglement for computing purposes, and therein lies the explanation of many

The quantum database is effectively distributed over a multitude of universes

the two polarized particles decohere simultaneously no matter the physical distance between them, meaning the information jump can exceed the speed of light. The effect was confirmed by experiment in the late twentieth century. Any device that uses this phenomenon to communicate messages is called an ansible, and these devices have been constructed, but undesired decoherence has meant the maximum distance between ansibles has been nine centimeters, and this only when both were cooled to one millionth of a K above absolute zero. Physical limitations strongly suggest further progress will be asymptotic at best

powerful but isolated and discrete, somewhat like brains

questions of Penrose quantum effects in the brain have been effectively rendered moot, as these also occur in qubes by definition. If both structures are quantum computers, and one of them we are quite certain has consciousness, who is to say what’s going on in the other

human brain operations have a maximum theoretical speed of 10
¹⁶
operations per second

computers have become billions to trillions times faster than human brains. So it comes down to programming; what are the operations actually doing

hierarchical levels of thought, generalization, mood, affect, will

super-recursive algorithms, hypercomputation, supertasks, trial-and-error predicates, inductive inference machines, evolutionary computers, fuzzy computation, transrecursive operators,

if you program a purpose into a computer program, does that constitute its will? Does it have free will, if a programmer programmed its purpose? Is that programming any different from the way we are programmed by our genes and brains? Is a programmed will a servile will? Is human will a servile will? And is not the servile will the home and source of all feelings of defilement, infection, transgression, and rage?

could a quantum computer program itself?

W
ahram saw Swan emerge from the lock door, looking around for him, and when she saw him, he waved, and then she did too, her expression pinched, he thought, her head tilted to the side. She looked at him in quick glances—she didn’t know how he would be. Suddenly he remembered that in the actual flesh she was a big bag of problems. He nodded a little deeper than he would have normally, trying to reassure her, and then thought that that might not be enough, and extended both hands, realizing as he did so that he was already back in a different world, Swancentric and intense. She threw herself on him in a rush, and he felt sure it looked like he was hugging back, or had even invited the hug.

Jean Genette emerged from the lock and stood looking up at them, and Wahram greeted him with another bow.

“So you want to find one of the hanging ships?” he said.

They did. Apparently it might have something to do with the attack on Terminator. So Wahram led them across the spaceport to the gate for the railgun launcher angled to send ferries into polar orbits around Saturn. These orbits were popular for viewing the rings and the hexagonal storm at Saturn’s south pole. Wahram had already gotten permission from the authorities to take a cloud diver into the upper reaches of the planet; probably the council was happy to have him involved, as the Saturnian liaison to the incursion.

They took off with only a pilot and crew aboard with them, and after they were cast toward the north pole, Swan and the inspector
told Wahram what they had been doing since they’d left Mercury. Wahram, feeling uneasy that he could not fully reciprocate and tell them about his activities, given the council’s orders, compensated by asking them a lot of questions about the investigation and its results so far. These turned out to be very interesting, even disturbing, and Wahram pondered to the point of a certain distraction the idea that there might be someone out there killing whole terraria. That the investigation had reduced their likeliest suspect pool to the population of Earth did not strike him as remarkable progress. All trouble comes from Earth, as the saying had it.

The cloud diver was not a big ship, and though it was very fast, the trip still took long enough for Swan to begin to exhibit the signs of distress and antsiness he remembered so well. Then happily they were above Saturn’s north pole, looking down at the dark side of the rings, as it was the northern winter. From behind the sun the rings were peach in tone, the circumferential scoring so finely etched and yet so vast that one could not help being a bit taken aback. Even on their dark side the rings were far brighter than the nightside of the planet, making for an aura or halo effect of eldritch beauty, all framing the deep blue of Saturn’s winter north.

Swan stared out the window, floating in her restraints, for the moment speechless. Wahram enjoyed this response, and not just because of the relief of the sudden silence. For him the polar view of Saturn was a perpetually glorious thing, the finest view in the solar system.

Down they dove toward the big planet, until it lost its sphericity and became a gorgeous pastel cobalt—the blue floor of the universe, it seemed, with the black of space only slightly domed over it. It looked almost like two planes only slightly separated, blue and black, meeting at the horizon like planes in elliptic geometry.

Soon after that they were down among the stupendous thunderhead armadas tearing east in this particular zone, around the seventy-fifth latitude. Royal blue, turquoise, indigo, robin’s egg—an
infinity of blue clouds, it seemed. In the latitudinal band farther south the wind flew hard in the opposite direction; two thousand–kilometer–per–hour jet streams were therefore running against each other, making the shear zone a wild space of whirlpooling tornadoes. It was important to keep a distance from such a violent interface, but as the latitudinal bands were thousands of kilometers wide, this was not difficult.

Unlike Jupiter, there were no radiation fields created by the smaller giant, so over years a not-insignificant population of floating ships had taken refuge in the upper clouds of Saturn; also some platform habitats, hung from immense balloons. The balloons had to be exceptionally large to provide any buoyancy, but once they did, the clouds provided shelter that was variously physical, legal, and psychological. The league kept track of these cloud floaters when possible, but if they sank deep enough in the clouds and went quiet, they could be elusive.

Now their little diver flew among thunderheads a hundred kilometers tall, and though it was a commonplace to say that perspective was lost in situations like this, such that all sizes looked much the same, it wasn’t really true: these thunderheads were clearly as big as entire asteroids, rising out of a deeper array of flatter cloud formations so that they saw below them masses of nimbus and cirrus, cumulus, festoons, barges—really the whole Howard catalog, all snarling through and over and under each other and constituting what passed for the surface of the gas giant. Off to the distant south they could still sometimes make out the nearest shear line and its ripping tornado funnels, its broad-domed hurricane tops. Sometimes in the middle of their own band they flew over a slower funnel and could look deep into the blue depths of the planet, gaseous for as far as they could see and much farther, but in appearance much like holes of mist that gathered at their bottoms to liquid. Every once in a while a high stray cloud would prove unavoidable, and the view out of the craft would suddenly
reduce to a dim blue flashing, and a tumultuous tremor would buck the craft in ways that even the quickness of the pilot AIs could not entirely damp. They would tremble and toss until they regained the clear blue again, now bluer than ever. For the most part they moved downstream with the flow of the wind, but also made the occasional reach across it. Resisting the wind too much threw them around about as much as being inside a cloud.