Death's End (The Three-Body Problem)

by Cixin Liu

  He piloted the pinnace to the stern of the ship, where he could see the three giant nozzles of the fusion drive. The engine wasn’t on, and the fusion reactor was kept at minimal power so that the nozzles only showed a faint red glow, reminding him of the clouds back on Earth at dusk.

  Petty Officer Liu was glad that he hadn’t made a report. An officer might get therapy, but an NCO like himself would be forced into hibernation. Like Ike, Liu Xiaoming didn’t want to return to Earth a useless man.

  Dr. West went to find Guan Yifan, a civilian scholar who worked in the observatory at the stern. Guan had a midship cabin assigned to him as living quarters, but he rarely went there. Most of the time, he remained in the observatory and asked the service robots to bring his meals. The crew referred to him as “the hermit at the stern.”

  The observatory was a tiny spherical cabin where Guan lived and worked. His appearance was disheveled, with an unshaven face and long hair, but he still looked relatively youthful. When West saw Guan, he was floating in the middle of the cabin, looking restless: sweaty forehead, anxious eyes, his hand pulling at his collar as if he was unable to catch his breath.

  “I already told you on the phone: I’m working and don’t have time for a visit.”

  “It’s precisely because your call betrayed signs of mental disorder that I came to see you.”

  “I’m not a member of the space force. As long as I’m no danger to the ship or the crew, you have no power over me.”

  “Fine. I’ll leave.” West turned around. “I just don’t believe that someone with claustrophobia can work in here without trouble.”

  Guan called out for West to stop, but West ignored him. As he expected, Guan chased after him and stopped him. “How did you know that? I am indeed... claustrophobic. I feel like I’m being packed into a narrow tube, or sometimes squeezed between two iron plates until I’m flat as a sheet....”

  “Not surprising. Look at where you are.” The doctor indicated the cabin—it resembled a tiny egg nestled in a nest of crisscrossing cables and pipes. “You research phenomena at the largest scale, but you stay in the smallest space. And how long have you been here? It’s been four years since your last hibernation, hasn’t it?”

  “I’m not complaining. Gravity’s mission is bringing fugitives to justice, not scientific exploration. I’m grateful to have this space at all.... Look, my claustrophobia has nothing to do with this.”

  “Why don’t we take a walk on Plaza One? It will help.”

  The doctor pulled Guan Yifan along, and the two drifted toward the bow of the ship. If the ship were accelerating, going from the stern of the ship to the bow would be equivalent to climbing up a one-kilometer well, but in the weightlessness of coasting, the trip was a lot easier. Plaza #1 was located at the bow of the cylindrical ship, under a semispherical, transparent dome. Standing there was like standing in space itself. Compared to the holographic projections of the star field on the walls of spherical cabins, this place induced an even stronger sense of the “desubstantiation effect.”

  “Desubstantiation effect” was a concept from astronautic psychology. Humans on Earth were surrounded by objects, and the image of the world in their subconscious was thus material and substantial. But in deep space, away from the Solar System, the stars were only distant points of light and the galaxy was nothing more than a luminous mist. To the senses and the mind, the world lost its materiality, and empty space dominated. A space voyager’s subconscious image of the world thus became desubstantiated. This mental model was the baseline in astronautic psychology. Mentally, the ship became the only material entity in the universe. At sub-light speeds, the motion of the ship was undetectable, and the universe turned into one boundless, empty exhibition hall. Here, the stars were illusions, and the ship was the only object on display. This mental model brought with it a profound sense of loneliness, and it could cause the voyager to have subconscious delusions of being a “superobserver” toward the lone “object on display.” This feeling of being completely exposed could lead to passivity and anxiety.

  Thus, many of the negative psychological effects of deep-space flight were due to the extreme openness of the external environment. In West’s extensive professional experience, it was extremely rare to develop claustrophobia the way Guan Yifan did. Even stranger to West was the fact that Guan did not seem relieved by the vast, open sky of Plaza #1; the restlessness caused by claustrophobia seemed to abate not one whit. This tended to support Guan’s assertion that his claustrophobia had nothing to do with the narrow confines of his observatory. West grew even more interested in his case.

  “Don’t you feel better?”

  “No, not at all. I feel trapped. Here, everything is so... enclosed.”

  Guan glanced at the starry sky and then focused his gaze in the direction Gravity was heading. The doctor knew he was looking for Blue Space. The two ships were now only one hundred thousand kilometers apart, and coasting at approximately the same speed. At the scale of deep space, the two ships were practically flying in close formation. The leadership of both ships was in the process of negotiating the technical details of their docking. But Blue Space was still too far away to be seen with the naked eye. The droplets were invisible as well. Based on the agreement made with Trisolaris half a century ago, the droplets had shifted to a position about three hundred thousand kilometers from both Gravity and Blue Space. The two ships and the droplets formed a narrow isosceles triangle.

  Guan Yifan turned his gaze back to West. “Last night, I had a dream. I went somewhere, somewhere really open, open in a way that you can’t even imagine. After I woke up, reality felt very enclosed and narrow, and that was how I came to be claustrophobic. It’s like... if, as soon as you were born, you were locked inside a small box, you wouldn’t care because that was all you’ve known. But once you’ve been let out and they put you back in, it feels completely different.”

  “Tell me more about this place in your dream.”

  Guan gave the doctor a mysterious smile. “I will describe it to the other scientists on the ship, maybe even the scientists on Blue Space. But I won’t tell you. I don’t have anything against you, Doctor, but I can’t stand the attitude shared by everyone in your profession: If you think someone has a mental disorder, you treat everything he says as merely the delusion of a diseased mind.”

  “But you just told me it was a dream.”

  Guan shook his head, struggling to remember. “I don’t know if it was a dream; I don’t know if I was awake. Sometimes, you can think you’re waking from a dream, only to find yourself still dreaming; other times, you’re awake, but it seems like you’re dreaming.”

  “The second situation is extremely rare. If you experienced that, then it was almost certainly a symptom of some mental disorder. Oh, sorry, now you’re unhappy with me again.”

  “No, no. I think we’re actually very similar. We both have our targets of observation. You observe the deranged, and I observe the universe. Like you, I also have some criteria for evaluating whether the observed objects are sound: harmony and beauty, in the mathematical sense.”

  “Of course the objects you observe are sound.”

  “But you’re wrong, Doctor.” Guan pointed at the glowing Milky Way, but his gaze remained on West, as though showing him some monster that had suddenly appeared out of nowhere. “Out there is a patient who may be mentally sound, but whose body suffers from paraplegia!”

  “Why?”

  Guan curled up and hugged his knees. The movement caused his body to slowly rotate in place. The magnificent Milky Way revolved around him, and he saw himself as the center of the universe.

  “Because of the speed of light. The known universe is about sixteen billion light-years across, and it’s still expanding. But the speed of light is only three hundred thousand kilometers per second, a snail’s pace. This means that light can never go from one end of the universe to the other. Since nothing can move faster than the speed of light, it follows that n
o information and motive force can go from one end of the universe to the other. If the universe were a person, his neural signals couldn’t cover his entire body; his brain would not know of the existence of his limbs, and his limbs would not know of the existence of the brain. Isn’t that paraplegia? The image in my mind is even worse: The universe is but a corpse puffing up.”

  “Interesting, Dr. Guan, very interesting!”

  “Other than the speed of light, three hundred thousand kilometers per second, there’s another three-based symptom.”

  “What do you mean?”

  “The three dimensions. In string theory, excepting time, the universe has ten dimensions. But only three are accessible at the macroscopic scale, and those three form our world. All the others are folded up in the quantum realm.”

  “I think string theory provides an explanation.”

  “Some think that it is only when two strings encounter each other and some qualities are canceled out that the dimensions are unfolded into the macroscopic, and dimensions above three will never have such chances for encountering each other.... I don’t think much of this explanation. It is not mathematically beautiful. Like I said, this is the universe’s three and three hundred thousand syndrome.”

  “What do you propose as the cause?”

  Guan laughed uproariously and put his arm around the doctor’s shoulders. “Great question! I don’t think anyone has thought this far. I’m sure there’s a root cause, and it might be the most horrifying truth that science is capable of revealing. But... Doctor, who do you think I am? I’m nothing more than a tiny observer curled up in the tail of a spaceship, and only an assistant researcher at that.” He released West’s shoulders, and, facing the galaxy, let out a long sigh. “I’ve been in hibernation the longest of anyone aboard. When we left Earth, I was only twenty-six, and even now I’m only thirty-one. But in my eyes, the universe has already transformed from a source of beauty and faith into a bloating corpse. I feel old. The stars no longer hold any attraction for me. I want to go home.”

  Unlike Guan Yifan, West had been awake for much of the voyage. He always believed that to maintain the mental health of others, he needed to keep his own emotions under control. But something seemed to buffet his heart now, and as he reviewed his own half century of travels, his eyes moistened. “My friend, I’m old, too.”

  As if in response to their conversation, the battle alert klaxons blared, sounding like the entire sky full of stars was screaming. Warning information scrolled on floating windows that appeared above the plaza. The overlapping windows sprang up one after another and quickly covered the Milky Way like colorful clouds.

  “Droplet attack!” West said to the confused Guan Yifan. “They’re both accelerating. One is headed for Blue Space, the other for us!”

  Guan looked around, instinctively searching for something to grab on to in case the ship accelerated. But there was nothing around. In the end, he held on to the doctor.

  West held his hands. “There won’t be enough time for any evasive maneuvers. We have only a few seconds left.”

  After a brief panic, both felt an unexpected sense of relief. They were glad that death would arrive so quickly that there wasn’t even time to be terrified. Perhaps their discussion about the universe was the best preparation for death.

  They both thought of the same thing, but Guan spoke it aloud first. “Looks like neither of us needs to worry about our patients anymore.”

  Deterrence Era, Year 62 November 28, 4:00 P.M. to 4:17 P.M.: Deterrence Center

  The high-speed elevator continued to descend, and the increasing layers of earth above seemed to put all their weight on Cheng Xin’s heart.

  Half a year ago, a joint session of the UN and the Solar System Fleet had elected Cheng Xin to succeed Luo Ji as the Swordholder and given her authority to control the gravitational wave deterrence system. She had received almost twice as many votes as the next candidate. She was now proceeding to the Deterrence Center in the Gobi Desert, where the deterrence authority handover ceremony was to take place.

  The Deterrence Center was the deepest man-made structure ever, about forty-five kilometers beneath the surface. This location was already below the crust, past the Mohorovičić discontinuity, in the mantle of the Earth. The pressure and temperature here were both far higher than in the crust, and the stratum around her was made up mostly of solid, hard peridotite.

  The elevator took almost twenty minutes to reach its terminus. Cheng Xin stepped out of the elevator and saw a black steel door. White text on the door gave the formal name for the Deterrence Center: Gravitational Wave Universal Broadcast System Control Station Zero. The insignias of the UN and the Solar System Fleet were embossed on the door.

  This ultra-deep structure was quite complex. It possessed its own independent air circulation system and was not directly connected with the atmosphere above the surface—otherwise, the high air pressure generated by a depth of forty-five kilometers would cause great discomfort to the occupant. It was also equipped with a powerful cooling system to withstand the high temperature of the mantle, nearly five hundred degrees Celsius.

  All Cheng Xin could see, however, was emptiness. The lobby’s walls could all apparently act as electronic displays, but they showed nothing but whiteness, as though the building wasn’t in use yet. Half a century ago, when the Deterrence Center was designed, Luo Ji had been consulted, but he had only provided one piece of input:

  As simple as a tomb.

  The handover ceremony was a solemn occasion, but the bulk of it had been held on the surface forty-five kilometers above. There, all the leaders of Earth International and Fleet International, representing all of humanity, had gathered, and they watched as Cheng Xin entered the elevator. Only two people would oversee the final handover: the PDC chair and the chief of staff for the Solar System Fleet, representing the two institutions directly operating the deterrence system.

  The PDC chair pointed at the empty lobby and explained to Cheng Xin that they would redecorate the place based on her ideas. If she wanted, she could have a lawn, plants, a fountain, and so forth. She could also choose to have a holographic simulation of scenes from the surface.

  “We don’t want you to live like him,” said the chief of staff. Perhaps because of his military uniform, Cheng Xin saw in him traces of men of the past, and his words warmed her slightly. But the heavy weight on her heart, as heavy as the forty-five kilometers of earth above her, did not lessen.

  Excerpt from A Past Outside of Time The Choice of the Swordholder: Ten Minutes Between Existence and Annihilation

  The first dark forest deterrence system consisted of more than three thousand nuclear bombs wrapped in an oil film substance deployed in orbit around the sun. After detonation, the film would cause the sun to flicker and broadcast the location of Trisolaris to the universe. Although the system was grand, it was extremely unstable. After the droplets stopped blockading electromagnetic radiation from the sun, a transmission system based on using the sun as a superantenna was immediately put in place to supplement the nuclear bomb deterrence system.

  Both of these systems relied on electromagnetic radiation, including visible light, as the broadcast medium. We now know that this is the most primitive technique for interstellar communication, equivalent to smoke signals in space. Since electromagnetic waves decay and become distorted rapidly, the broadcast range is limited.

  At the time of the founding of deterrence, humankind already had a basic grasp of the technology for detecting gravitational waves and neutrinos, but they lacked the ability to modulate and transmit. These were the very first technologies humans demanded from Trisolaris. Compared to quantum communications, these technologies were still primitive, since both gravitational waves and neutrinos were limited by the speed of light, but they were a whole level above electromagnetic waves.

  Both of these means of transmission decayed relatively slowly and had very long broadcast ranges. Neutrinos, in particular, interacted
with almost nothing else. Theoretically, a modulated beam of neutrinos could transmit information to the other end of the universe, and the accompanying decay and distortion would not affect the decoding of the information. But while neutrinos must be focused in a particular direction, gravitational waves were omnidirectional, thus gravitational waves became the main method of establishing dark forest deterrence.

  The fundamental principle of gravitational wave transmission relied on the vibration of a long string of extremely dense matter. The ideal transmission antenna would involve a large number of black holes connected together to form a chain that generated gravitational waves as it vibrated. But even Trisolaris didn’t possess such a level of technology, and humankind had to resort to constructing the vibrating string out of degenerate matter. The extremely dense degenerate matter packed an enormous mass into strings mere nanometers in diameter. A single string took up only a minuscule portion of the giant antenna, the bulk of which consisted of support and protection for the ultra-dense string. Thus, the total mass of the antenna wasn’t extraordinarily large.

  The degenerate matter forming the vibrating string was naturally found in white dwarves and neutron stars. Under typical conditions, this substance naturally decayed and turned into regular matter over time. Man-made vibrating strings typically had a half-life of around fifty years, beyond which the antennas lost their effectiveness. Thus, every half century, the antennas needed to be refreshed with new ones.

  During the earliest stage of gravitational wave deterrence, the main strategic concern was with ensuring deterrence power. Plans were made to build a hundred broadcasting stations scattered around the continents. But gravitational wave communication suffered from a flaw: The transmission equipment could not be miniaturized. The complex, gigantic antennas were extremely costly to manufacture, and in the end only twenty-three gravitational transmitters were built. But the focus on ensuring deterrence finally faded, due to another event.