by Cixin Liu
“I guess paintings take up a lot of space, too,” said AA.
Luo Ji picked up a set of work overalls from on top of another box and retrieved a small knife and screwdriver from the pockets. “The frame takes up a lot of space. You can take it off.”
AA picked up the screwdriver, but before she could get started on the painting, Cheng Xin cried out. “No!” The painting was Van Gogh’s Starry Night.
Cheng Xin’s surprise wasn’t just because the painting was valuable. She had seen it once before. Four centuries ago, right after she had started working at the PIA, she had visited New York’s Museum of Modern Art on a weekend and saw a few of Van Gogh’s paintings. Van Gogh’s representation of space had left a deep impression on her. In his subconscious, space seemed to have structure. Cheng Xin wasn’t an expert in theoretical physics back then, but she knew that according to string theory, space, like material objects, was made up of many microscopic vibrating strings. Van Gogh had painted these strings: In his paintings, space—like mountains, wheat fields, houses, and trees—was filled with minute vibrations. Starry Night had left an indelible mark in her mind, and she was amazed to see it again four centuries later on Pluto.
“Get rid of the frame. That way, you can take more.” Luo Ji waved his cane carelessly. “Do you think these objects are still worth a city’s ransom? Now, even a city is worthless.”
And so they pried away the frame that was perhaps five centuries old, but they kept the hard backing to avoid damaging the painting by bending the canvas. They continued to do the same to other oil paintings, and soon, empty frames littered the floor. Luo Ji came over and put his hand on a small painting.
“Would you leave this one for me?”
Cheng Xin and AA moved the painting aside and set it on top of a box next to the wall. They were surprised to see that it was the Mona Lisa.
Cheng Xin and AA continued to work at disassembling frames. AA whispered, “Clever old man. He kept the most expensive piece for himself.”
“I don’t think that’s the reason.”
“Maybe he once loved a girl named Mona Lisa?”
Luo Ji sat next to the Mona Lisa and caressed the ancient frame with one hand. He muttered, “I didn’t know you were here. Otherwise I could have come to see you often.”
Cheng Xin saw that he wasn’t looking at the painting. His eyes stared ahead as if looking into the depths of time. Cheng Xin saw that his ancient eyes were filled with tears, and she wasn’t sure if she was mistaken.
Inside the grand tomb under the surface of Pluto, lit by the dim lamps that could shine for a hundred thousand years, Mona Lisa’s smile seemed to appear and disappear. The smile had puzzled humankind for nearly nine centuries, and it looked even more mysterious and eerie now, as though it meant everything and nothing, like the approaching Death.
Bunker Era, Year 68 The Two-Dimensional Solar System
Cheng Xin and AA carried the first batch of artifacts to the surface. Other than a dozen or so frameless paintings, they also carried two bronze ritual vessels from the Western Zhou Period and some ancient books. Under standard 1G gravity, they would not have been able to move all these, but with Pluto’s weak gravity, it didn’t require too much effort. Going through the air lock, they were careful to close the inner door first before opening the outer door, lest they and the artifacts be blown into the open by escaping air. As soon as they opened the outer door, the small amount of air inside the air lock turned into a flurry of ice crystals. Initially, they thought the ice crystals were illuminated by the searchlight on Halo, but after the flurry subsided, they realized that Halo’s searchlight had already shut off. Some source of light in space illuminated Pluto’s surface, and Halo and the black monolith cast long shadows on the white ground. They looked up, and backed up two steps with shock.
A pair of giant eyes stared down at them from space.
Two glowing ovals hung in space, looking exactly like eyes. The “whites” were white or light yellow, and the “irises” were dark.
“That’s Neptune, and the other one is Ura—oh, no, that’s Saturn!” AA said.
Both gas giants had been two-dimensionalized. Uranus’s orbit was outside Saturn’s, but since Uranus was currently on the other side of the Sun, Saturn had fallen into the two-dimensional plane first. The giant planets ought to look like circles after collapsing, but due to the angle of view from Pluto, they appeared as ovals. The two-dimensional planets showed up as clear, concentric rings. Neptune consisted mainly of three rings: the outermost was blue, bright and vivid, like lashes and eye shadow—that was the atmosphere of hydrogen and helium. The middle ring was white—that was the twenty-thousand-kilometer mantle, which astronomers thought of as a water-ammonia ocean. The dark center was the core, formed of rocks and ice, with a mass equal to the entire Earth. Saturn’s structure was similar, except it didn’t have the outer blue ring.
Each large ring was composed of many smaller rings, full of detailed structures. As they examined the planets further, the two giant eyes now more resembled the rings of a newly felled tree. Around each two-dimensional planet were a dozen or so small circles—moons that had also been flattened. Around Saturn was another faint large circle—its rings. They could still find the Sun in the sky, a small disk emitting faint yellow light. Since the two planets were still on the other side of the sun, their area after collapsing into two dimensions was breathtaking.
Both planets had no thickness anymore.
In the light emitted by these two-dimensional planets, Cheng Xin and AA carried the artifacts across the white landing field toward Halo. The ship’s smooth, streamlined body was like a funhouse mirror, and the reflections of the two-dimensional planets were stretched into long, flowing shapes. The yacht’s profile naturally made people think of droplets, and evinced a comforting strength and lightness. On the way to Pluto, AA had told Cheng Xin that she thought Halo’s hull was probably made up in large part of strong-interaction materials.
As they approached, the door on the bottom of the ship slid open noiselessly. They carried the artifacts up the airstair and into the cabin, took off their helmets, and took a deep breath in their cozy little world. Relief filled their hearts—without consciously being aware of it, they already thought of the yacht as home.
Cheng Xin asked the ship’s AI whether it had received any transmissions from Neptune and Saturn. As soon as she made the request, information windows flooded forth like a colorful avalanche that threatened to bury them. The scene reminded them of the first false alarm of 118 years ago. Back then, most of the information had come from media reports, but now, the news media seemed to have disappeared. Most of the information windows contained no discernible images at all—some were blurred, others shook, and most showed meaningless close-ups. But a few of the windows were filled with patches of gorgeous color which, as they flowed and shifted, revealed complex, detailed structures. They probably showed the two-dimensional universe.
AA asked the AI to filter the images. The AI asked them what kind of information they wanted. Cheng Xin asked for information about the space cities. The flood of windows cleared and was replaced by about a dozen others arranged in order. One of the windows enlarged and moved before the others. The AI explained that this had been taken twelve hours ago at Europe VI in the Neptune cluster. The city had once been part of a combined city that had separated after the strike alert.
The image was stable, and the field of view wide. The camera was probably at one end of the city, and almost the entire city could be seen.
Electricity had gone out in Europe VI, and only a few searchlight beams projected unsteady circles of light onto the city’s far side. The three artificial fusion suns along the city’s axis had all turned into silvery moons, giving out only illumination, but no heat. This was a standard football-shaped city, but the buildings inside the city were very different from what Cheng Xin had seen half a century ago. The Bunker World had prospered, and the buildings inside the city were no l
onger monotonous and uniform. They were much taller, and each had a unique design. The tips of some of the skyscrapers almost touched the axis of the city. Buildings in the shapes of trees reappeared as well, and they looked about as large as the ones that had been built on Earth, though the leaves hung more densely. It was possible to imagine the city’s beauty and magnificence when lit up at night. But now, only cold moonlight illuminated it, and the tree-buildings cast wide shadows so that the rest of the city appeared as ruins nestled in the shade of a giant forest.
The city had stopped spinning and everything was weightless. Countless objects floated through the air—vehicles, miscellaneous goods, and even entire buildings.
A black belt of clouds appeared along the city’s axis, connecting the two poles. The ship’s AI outlined a rectangular region in the image and zoomed in, creating a new information window. Cheng Xin and AA were shocked to see that the black cloud was formed from people drifting in the middle of the city! Some of the weightless individuals had pulled together into a cluster; some had linked hands and formed a line; but most floated alone. Everyone wore helmets and clothes that covered all parts of their body—most likely space suits. Even during Cheng Xin’s last time out of hibernation, it was hard to tell everyday clothes apart from space suits. Everyone seemed to have a pack for life-support systems—some wore it on their back, while others held it in their hands. But most people had their visors open, and it was possible to see a light breeze blowing through the city, indicating that the city still retained a breathable atmosphere. Many had congregated around the suns, perhaps hoping for more light as well as a bit of warmth, but the light emitted by the fusion suns was cold light. The silvery light shone through cracks in the people-cloud and turned into dappled shadows in the surrounding city.
According to the ship’s AI, of the six million inhabitants of Europe VI, half had already left the city on space vehicles. Of the remaining three million, some had no way to get off the city, but most understood that any attempt at escape was hopeless. Even if some ships miraculously managed to escape the collapsing zone and reached outer space, most ships had no ecological cycling system to maintain life for long. Access to stellar ships that could survive indefinitely in outer space was still a privilege of the very few. These people chose to wait for the end in a place they were familiar with.
The transmission wasn’t muted, but Cheng Xin couldn’t hear anything. The people-cloud and the city were both eerily quiet. Everyone looked in one direction. That part of the city looked no different from any other, filled with crisscrossing streets and row upon row of buildings. Everyone waited. In the watery, cold moonlight, people’s faces appeared as white as ghosts. The sight reminded Cheng Xin of the bloody dawn in Australia 126 years ago. Like then, Cheng Xin felt as though she were looking down upon an ant colony, and the black people-cloud looked just like a drifting swarm of ants.
Someone in the people-cloud screamed. A glowing dot appeared at a spot on the city’s equator, the same spot where everyone had been gazing. It was like a small opening in the roof of a dark house letting in the sunlight.
That was where Europe VI first came into contact with two-dimensional space.
The light grew rapidly and turned into a glowing oval. The light it emitted was sliced into many shafts by the tall buildings all around, and illuminated the people-cloud on the city’s axis. The space city now resembled a giant ship whose bottom had been breached, sinking in a flat sea. The plane of the two-dimensional space rose like water, and everything that came into contact with the surface instantaneously turned into two dimensions. Clusters of buildings were cut, and their two-dimensional images spread out on the plane. Since the city’s cross section was but a small portion of the entire flattened city, most of the two-dimensionalized buildings had expanded beyond the oval marked by the city’s hull. On the rising, expanding plane, gorgeous colors and complicated structures flashed by and zoomed away in every direction, as though the plane was a lens through which one could see colorful beasts running. Because the city still possessed air, they could hear the sound of the three-dimensional world falling into two dimensions: a crisp, piercing series of crunches, as though the buildings and the city itself were made of exquisitely carved glass and a giant roller was crushing everything.
As the plane continued to rise, the people-cloud began to spread out in the opposite direction, like a curtain being lifted by an invisible hand. The scene reminded Cheng Xin of a massive flock of millions of birds that she had seen once. The flock had seemed like a unified organism changing shape in the dusk sky.
Soon, the plane had swallowed one-third of the city, and it continued to flicker frantically as it rose irresistibly toward the axis. Some people had begun to fall into the plane by now. They either fell behind due to malfunctions in their space suit thrusters or they had given up on running. Like drops of colorful ink, they spread open on the plane in an instant, and each appeared as a unique figure in two dimensions. On one of the zoomed-in images shown by the AI, they saw a pair of lovers leaping into the plane while in an embrace. Even after the two had been flattened, it was possible to see the figures in an embrace lying side by side—their postures appeared odd, as though drawn by a clumsy child who did not understand the principles of perspective. Nearby there was a mother who lifted her baby overhead as she fell into the plane, all so that the baby would survive for an extra tenth of a second. The mother and child were also vividly portrayed in this giant painting. As the plane kept on rising, the rain of people falling on it became denser. Two-dimensional human figures flooded forth on the plane, most moving outside the boundary of the space city.
By the time the two-dimensional space approached the axis, most of the surviving population had landed against the city’s far side. Half of the city was now gone, and as people looked “up” they could no longer see the familiar city on the other side, but only a chaotic, two-dimensional sky pressing down on the parts of Europe VI that remained in three dimensions. It was now no longer possible to escape from the main gateway at the north pole, so people congregated around the equator, where there were three emergency exits. The weightless crowd piled into mountains around the exits.
The two-dimensional space passed through the axis and swallowed up the three suns, but the light emitted by the two-dimensionalizing process made the world even brighter.
A low whistling sound began: The city was losing its air to space. The three emergency exits along the equator were wide open, each as large as a football field; outside them was the still-three-dimensional space.
The ship’s AI pushed another information window to the front. This was a feed from space looking down at Europe VI. The two-dimensionalized portion of the space city spread across the invisible plane, making the rapidly sinking, still-three-dimensional portion look minuscule by comparison, like the back of a whale peering out of the vast ocean. Three clumps of black smoke rose out of the city and dissipated in space; the “smoke” was formed from the people blown out by the fierce winds of the decompressing space city. The lonely, three-dimensional island continued to sink and melt into the two-dimensional sea. In less than ten minutes, all of Europe VI had turned into a painting.
The painting of Europe VI was so vast that it was hard to estimate its exact area. It was a dead city, but perhaps it was more accurate to call it a 1:1 drawing of the city. The drawing reflected every detail of the city, down to every screw, every fiber, every mite, and even every bacterium. The precision of the drawing was at the level of the individual atom. Every atom in the original three-dimensional space was projected onto its corresponding place in two-dimensional space according to ironclad laws. The basic principles governing this drawing were that there could be no overlap and no hidden parts, and every single detail had to be laid out on the plane. Here, complexity was a substitute for grandeur. The drawing wasn’t easy to interpret—it was possible to see the overall plan of the city and recognize some big structures, such as the giant trees, which st
ill looked like trees even in two dimensions. But buildings looked very different after being flattened: it was almost impossible to deduce the original three-dimensional structure from the two-dimensional drawing by imagination alone. However, it was certain that image-processing software equipped with the right mathematical model would be able to.
In the information window, it was also possible to see two other flattened space cities in the distance. The cities appeared as perfectly flat continents drifting in dark space, gazing at each other across the plane. But the camera—perhaps located on a drone—was also falling toward the plane, and soon the two-dimensional Europe VI filled the screen.
Close to a million people had escaped Europe VI via the emergency exits; now, caught by the three-dimensional space around them collapsing into two dimensions, they fell toward the plane like a swarm of ants caught in a waterfall. A majestic rain of people fell onto the plane, and the two-dimensional human figures in the city multiplied. Flattened persons took up a lot of area—though still minuscule compared to the vast two-dimensional buildings—and resembled tiny, barely man-shaped marks in the immense picture.
More objects appeared in three-dimensional space in the information window: the skiffs and dinghies that had left Europe VI earlier. Their fusion reactors were operating at maximum capacity, but they still fell inexorably toward the plane. For a moment, Cheng Xin thought the blue flame of the fusion drives penetrated that depthless plane, but the plasma had simply been two-dimensionalized. In those areas, the two-dimensional buildings were distorted and twisted by the two-dimensional flames. Next, the skiffs and dinghies became part of the giant drawing. Obeying the no-overlapping principle, the two-dimensionalized city expanded to give these new objects space, and the whole image resembled spreading ripples on the surface of a pond.