Death's End (The Three-Body Problem)

by Cixin Liu

  Cheng Xin sat down as well and leaned on his shoulder. She laughed as she said, “You’re the only man in this universe. I don’t think you need to give me anything.”

  The feeling of being alone in the universe was soon shattered by the sound of a door opening. A figure in white came out of the house and walked toward them. The world was so small that it was possible to clearly see anyone at any distance. They saw that the newcomer was a woman dressed in a kimono. The kimono, decorated with tiny red flowers, was like a walking flower bush that brought the feeling of spring to the universe.

  “Sophon!” Cheng Xin cried out.

  “I know her,” Yifan said. “She’s the robot controlled by sophons.”

  They walked over to meet the woman under one of the trees. Cheng Xin saw that it really was Sophon: That unparalleled beauty remained unchanged.

  Sophon bowed deeply to Cheng Xin and Guan Yifan. When she straightened, she smiled at Cheng Xin. “I said that the universe is grand, but life is grander. Fate has indeed directed us to meet again.”

  “I couldn’t have imagined,” Cheng Xin said. “I’m really glad to see you. Really.” Sophon brought her to the past—more than eighteen million years ago. But that wasn’t really accurate, because they were now in another time stream altogether.

  Sophon bowed again. “Welcome to Universe 647. I am its manager.”

  “The manager of the universe?” Yifan looked at Sophon, astounded. “What a grand title! For a cosmologist like me, that sounds like—”

  “Oh no!” Sophon laughed and waved his remark away. “You are the true masters of Universe 647 and have full authority over everything here. I’m just here to serve you.”

  Sophon made a gesture indicating that they should follow her. They followed her to a refined parlor inside the house. The parlor was decorated in an Eastern style with a few calming brush paintings and calligraphy scrolls hung on the walls. Cheng Xin looked for artifacts taken from Pluto by Halo but didn’t find any. After they sat down at an antique wooden desk, Sophon poured tea for them—without going through the complicated steps of the Way of Tea. The tea leaves seemed to be Longjing, and they stood up at the bottom of the cups like a tiny green forest, giving off a fresh fragrance.

  To Cheng Xin and Guan Yifan, everything seemed to be a dream.

  Sophon spoke. “This universe is a gift. Mr. Yun Tianming gave it to the both of you.”

  “I think it’s meant for Cheng Xin,” said Yifan.

  “No. You’re also one of the intended recipients. Your authorization was added to the recognition system later; otherwise you wouldn’t have been allowed in. Mr. Yun hoped that you could hide in this tiny universe and avoid the collapse of the great universe—or the big crunch—and, after the next big bang, enter the new universe and see its Edenic Age. Right now, we exist in an independent timeline. Time is passing rapidly in the great universe, and you will certainly be able to see its end within your lifetimes. More specifically, I estimate that the great universe will collapse into a singularity after about ten years here.”

  “If a new big bang occurs, how will we know?” asked Yifan.

  “We’ll know. We can sense the conditions in the great universe through the supermembrane.”

  Sophon’s words reminded Cheng Xin of what Yun Tianming and 艾 AA had carved into the rock. But Guan Yifan was reminded of something else. He noticed that Sophon spoke of the “Edenic Age” of the new universe. This was a term invented by the Galactic humans. Two possibilities presented themselves. One was that coincidentally, the Trisolarans had also picked this term. The second possibility was far more terrifying: the Trisolarans had already discovered the Galactic humans. Given how quickly Yun Tianming had arrived on Planet Blue, it was apparent that the First Trisolaran Fleet was very close to the worlds of humankind. And now, the Trisolaran civilization had developed to the point where they were capable of constructing small universes: This was a great threat to humanity.

  Then he laughed.

  “What are you laughing at?” Cheng Xin asked.

  “Myself.”

  He found himself ridiculous. More than eighteen million years had passed since the day he’d departed World II to come to Planet Blue, and that was before they entered this small universe with its own time. By now, hundreds of millions of years must have passed in the great universe. He was worried about truly ancient history.

  “Have you seen Yun Tianming?” Cheng Xin asked.

  Sophon shook her head. “No. I’ve never met him.”

  “What about 艾 AA?”

  “The last time I saw her was on Earth.”

  “Then how did you come to be here?”

  “Universe 647 was a custom order. I’ve been here since its completion. Remember that I am fundamentally just a collection of digital bits, and many copies of me can be made.”

  “Did you know that Tianming brought this universe to Planet Blue?”

  “I don’t know what Planet Blue is. If it’s a planet, then Mr. Yun couldn’t have brought Universe 647 to it, because this is an independent universe that does not exist within the great universe. He could only bring the entrance to the universe there.”

  “Why aren’t Tianming and AA here?” Yifan asked. This was also the question Cheng Xin most wanted answered. She hadn’t asked earlier because she was afraid of hearing an answer she didn’t want to know.

  Sophon shook her head again. “I don’t know. The recognition system has always had Mr. Yun’s authorization.”

  “Is anyone else’s authorization in the system?”

  “No. Only the three of you.”

  After a while, Cheng Xin said to Yifan, “AA always cared more than me about the world around her. I don’t think she would have been interested in a new universe tens of billions of years later.”

  “I’m interested,” said Yifan. “I really want to see what a new universe is like before it’s distorted and tampered with by life and civilization. I think it must exhibit the highest degree of harmony and beauty.”

  Cheng Xin said, “I also want to go to the new universe. The singularity and the new big bang will erase all memories of our universe. I want to bring some memory of humanity there.”

  Sophon nodded solemnly at Cheng Xin. “That is a great task you’ve set yourself. There are others doing similar work, but you’re the first human from the Solar System to do this.”

  “You’ve always had higher goals in life than I,” Yifan whispered to Cheng Xin. She couldn’t tell if he was joking or being serious.

  Sophon stood up. “Welcome to your new life in Universe 647. Why don’t we go outside and take a look around?”

  Outside, the spring planting was in full swing. The columnar robots were all working the fields. Some used the rakes to level and smooth out the field—the soil was so loose already that it did not need to be plowed; some were planting seeds in the parts that had already been smoothed. The farming techniques they employed were primitive: There were no drag harrows, so the robots had to use small rakes to level the field a bit at a time; there were no planters, so the robots each carried a bag of seeds and buried the seeds in the field one at a time. The entire scene invoked a sense of ancient simplicity. Here, robots seemed somehow more natural than real farmers.

  Sophon explained, “We have only enough food stored here to last two years. After that, you’ll need to rely on the food you grow. These seeds are descended from the seeds Cheng Xin sent along with Mr. Yun. Of course, they’ve all been genetically improved.”

  Yifan looked somewhat puzzled by the black soil. “I feel that soilless cultivation tanks would be more suitable here.”

  Cheng Xin said, “Anyone from the Earth has a kind of nostalgia for soil. Remember what Scarlett’s father told her in Gone With the Wind? ‘Why, land is the only thing in the world worth workin’ for, worth fightin’ for, worth dyin’ for, because it’s the only thing that lasts.’”

  Yifan said, “The Solar System humans spilled their last drop of blood to s
tay with their land—well, save for two drops: you and AA. But what was the point? They didn’t last, and neither did their land. Hundreds of millions of years have passed in the great universe, and do you think anyone still remembers them? This obsession with home and land, this permanent adolescence where you’re no longer children but are afraid to leave home—this is the fundamental reason your race was annihilated. I am sorry if I’ve offended you, but it’s the truth.”

  Cheng Xin smiled at the agitated Yifan. “You haven’t offended me. What you said is true. We knew that, but we couldn’t help it. You probably can’t help it, either. Don’t forget that you and all the crew of Gravity were prisoners before becoming Galactic humans.”

  “That is true.” Guan Yifan lost some of his fire. “I’ve never thought of myself as a man qualified for space.”

  By the standards of space, there were not too many “qualified” men—and it was doubtful Cheng Xin would like any of them. She did think of one person who was probably qualified. His voice still echoed in her ears: We’re going to advance! Advance! We’ll stop at nothing to advance!

  “Don’t dwell on the past,” Sophon said in her sweet voice. “Everything starts anew here.”

  A year passed in Universe 647.

  The wheat had been harvested twice, and Cheng Xin and Guan Yifan had now watched twice as the green seedlings gradually turned into a sea of golden stalks. The vegetable fields next to the wheat had always remained green.

  In this tiny world they were provided with all the other necessities of life. None of the objects had manufacturing marks or brand logos—Trisolarans made them—but they looked exactly like human products.

  Cheng Xin and Guan Yifan sometimes went into the fields to work alongside the robots. Sometimes they strolled about the universe—as long as they were careful not to leave footprints, they could keep on walking indefinitely and experience the feeling of traversing countless worlds.

  They spent most of their time in front of the computer, however. It was possible to invoke a terminal from anywhere in the small universe, but they didn’t know where the CPU for the computer was located. The computer had a massive databank of text, image, and video from the Earth, most of which dated from before the Broadcast Era. The Trisolarans had clearly gathered the info as they studied humanity, and the material covered every field in the sciences and the humanities.

  But even more information existed in the databank written in the Trisolaran language. This massive ocean of data was what interested them the most. Since they couldn’t find any software on the computer for translating Trisolaran writing into human languages, they had to study the Trisolaran script itself. Sophon acted as their teacher, but they soon discovered that this was an extremely difficult endeavor because Trisolaran writing was purely ideographic; unlike human scripts, which were mostly phonetic, Trisolaran writing had no connection to their speech, but expressed ideas directly. In the distant past, humans had also used ideographic scripts—such as some hieroglyphs—but most of these later disappeared.* Humans read by decoding speech made visible. However, the difficulty didn’t last long. The more they persisted, the easier the learning process became. After struggling for two months, they found themselves making rapid progress. Compared to phonetic scripts, the biggest advantage of an ideographic script was how fast one could read—Cheng Xin and Guan Yifan read at least ten times as fast in Trisolaran as they did with human scripts.

  They began to read the Trisolaran material in the databank—at first haltingly, and then faster. They had two initial goals in mind: First, they wanted to know how the Trisolarans had recorded the period of history between their civilization and Earth civilization. Second, they wanted to know how this mini-universe was constructed. For the latter, they understood that they would likely not achieve a specialist’s level of understanding, but they wanted to at least understand it at the level of popular science. Sophon estimated that in order to achieve these two goals, they would need to spend one year to learn how to read Trisolaran better, then take another year to read in depth.

  The fundamental principles underlying the small artificial universe seemed unimaginable to them; even the most basic mysteries puzzled them for the longest time. For instance, how could a complete ecological cycle function in a sealed space of only one cubit kilometer? What was the sun? What was its energy source? And most confounding: As a completely sealed system, where did the heat of the mini-universe go?

  They asked Sophon these questions. Some she could answer; for others, she referred them to materials in the computer.

  They also cared about the answer to one question in particular: Could the mini-universe communicate with the great universe? Sophon told them that there was no way for the mini-universe to transmit any information to the greater universe, but it was possible for the mini-universe to receive broadcasts from the great universe. She explained that all the universes were bubbles above a supermembrane—this was a fundamental conceptual image from Trisolaran physics and cosmology, and she could explain it no further. The great universe had enough energy to propagate information across the supermembrane. However, this was difficult and required a great expenditure of energy—the great universe would have to convert a Milky Way’s worth of matter into pure energy. As a matter of fact, the monitoring systems in Universe 647 often received messages from other great universes on the supermembrane. Some were natural phenomena; some were messages from intelligent beings that could not be decoded—but they had never received any message from the particular great universe they had come from.

  Time flowed by day after day like the smooth, placid water in that little brook.

  Cheng Xin began to write her memoir so that she could record the history she knew. She named the book A Past Outside of Time.

  Sometimes, they also tried to imagine life in the new universe. Sophon told them that according to cosmological theories, the new universe was certain to possess more than four macro dimensions, perhaps even more than ten macro dimensions. After the birth of the new universe, Universe 647 could automatically construct an entrance to it and examine the interior conditions. If the new universe possessed more than four dimensions, the mini-universe’s exit could be moved around until a suitable habitable location was found in the great universe. Simultaneously, their mini-universe could establish communications with the refugees of other Trisolaran mini-universes, or even with Galactic human migrants. In the new universe, all the migrants coming from the old universe would practically be one race, and should be able to work together to construct a new world. Sophon emphasized that one characteristic greatly increased the probability of survival in a high-dimensional universe: Out of the many macro dimensions, it was likely that more than one dimension would belong to time.

  “Multi-dimensional time?” Cheng Xin couldn’t understand the concept at first.

  “Even if time were only two-dimensional, it would be a plane instead of a line,” Yifan explained. “There would be an infinite number of directions, and we could simultaneously make countless choices.”

  “And at least one of those choices would turn out to be right,” added Sophon.

  One night, after the second harvest, Cheng Xin woke up to find Yifan not beside her. She got up, went outside, and saw that the sun had already turned to the moon, and the little world was immersed in the watery, cool light. She saw Yifan sitting by the brook, his posture morose.

  In this world of two, each of them had grown especially sensitive to the moods of the other. Cheng Xin had already known that something was troubling Yifan. Earlier, he had been sunny and upbeat. Until a few days ago, he had regularly shared his dream that, if they could find a peaceful life in the new great universe, perhaps their children could re-create the human race. But then he had abruptly changed, frequently going off by himself to ponder something, or to calculate something at a computer terminal.

  Cheng Xin sat down next to Yifan, and he pulled her into his arms. The moonlit world was very quiet, and all they
heard was the babbling brook. The moon revealed a field of ripe wheat; they’d have to start the harvest tomorrow.

  “Loss of mass,” Yifan said.

  Cheng Xin said nothing. She watched the moonlight dancing in the brook, knowing that Yifan was going to explain.

  “I’ve been reading Trisolaran cosmology, and came across a proof for the elegance of the mathematics behind the great universe we all came from. The design of the total mass in the universe was precise and perfect. The Trisolarans had proved that the total mass of the universe was just enough to allow the big crunch. If the total mass were reduced even slightly, the universe would turn from being closed to open, and expand indefinitely.”

  “But mass has been lost,” Cheng Xin said. She understood right away what he was getting at.

  “Yes. The Trisolarans have already constructed several hundred mini-universes. How many more have been constructed by other civilizations in the universe to escape the big crunch, or for some other purpose? Each of these mini-universes took away some matter from the great universe.”

  “We need to ask Sophon.”

  “I have. She told me that at the time of Universe 647’s completion, the Trisolarans had not observed any influence from the loss of mass in the great universe. That universe was closed and was certain to eventually collapse.”

  “What about after Universe 647 was constructed?”

  “She had no idea, of course. She also mentioned that there was a group of intelligent beings in the universe that resembled the Zero-Homers, but they called themselves the Returners. They advocated against the construction of mini-universes, and called for the mass in completed mini-universes to be returned to the great universe.... But she didn’t know much else about them. All right, let’s forget all this. We’re not God.”

  “But we’ve long been called on to think about matters that belonged to the province of God.”

  They sat by the brook until the moon turned into the sun again.

  Three days after the harvest, once all the wheat had been threshed and winnowed and stored away, Cheng Xin and Guan Yifan stood at the edge of the field and watched as the robots plowed the field to prepare for the next planting. The granary was now full, so there was no room for more wheat. Before, they would have debated what to plant for the next season. But now, both of them were troubled and had no interest in the topic. Throughout the entire harvest and threshing process, they had stayed in the house and discussed possible futures. They realized that even their individual life choices affected the fate of the universe, or even the fates of multiple universes. They really felt like God. The weight of responsibility made it hard to breathe, and so they left the house.