Death's End

by Cixin Liu

  Now you see what he’s made of.

  But … what if he’s telling the truth?

  If even we believe him, the enemy will believe him, too.

  Wade turned back to the rostrum, then seemed to remember something vital, and glanced back at Cheng Xin again.

  This is a fun game, isn’t it?

  Tianming’s unexpected refusal seemed to change the atmosphere in the hall. The last candidate, a forty-three-year-old HIV-positive American NASA engineer named Joyner, also refused to take the oath. She explained that she had not wanted to be here, but she had felt compelled to come because she believed that if she refused, her friends and family would despise her and leave her to die alone. No one knew if she was telling the truth or if Tianming had inspired her.

  The next night, Joyner’s condition suddenly deteriorated. An infection that turned into pneumonia caused her to stop breathing, and she died before dawn. The medical staff did not have enough time to remove her brain for flash freezing, and it was unusable.

  Tianming was chosen to carry out the mission of the Staircase Program.

  * * *

  The moment had arrived. Cheng Xin was informed that Tianming’s condition had suddenly deteriorated. They needed to remove his brain right away. The procedure would be conducted at Westchester Medical Center.

  Cheng Xin hesitated outside the hospital. She didn’t dare enter, but she couldn’t bear to leave. All she could do was to suffer. Wade, who had come with her, walked ahead toward the hospital entrance alone. He stopped, turned around, and admired her pain. Then, satisfied, he delivered the final blow.

  “Oh, I have another surprise for you: He gave you the star.”

  Cheng Xin stood frozen. Everything seemed to transform around her. What she had seen before were mere shadows; only now did life’s true colors reveal themselves. The tidal wave of emotion made her stumble, as if the ground had disappeared.

  She rushed into the hospital and dashed through the long, winding hallways until two guards outside the neurosurgery area stopped her. She struggled against them, but they held fast. She fumbled for her ID, waved it at them, and then continued her mad run toward the operating room. The crowd outside, surprised, parted for her. She slammed through the doors with glowing red lights over them.

  She was too late.

  A group of men and women in white coats turned around. The body had already been removed from the room. In the middle was a workbench, on top of which sat a cylindrical stainless steel insulating container, about a meter tall. It had just been sealed, and the white fog produced by the liquid helium still hadn’t completely dissipated. Slowly, the white fog rolled down the surface of the container, flowed across the workbench, cascaded over the edge like a miniature waterfall, and pooled on the floor, where it finally broke apart. In the fog, the container appeared otherworldly.

  Cheng Xin threw herself at the workbench. Her motion broke up the white fog, and she felt herself enveloped in a pocket of cold air that dissipated in a moment. It was as if she had briefly touched what she was seeking before losing it to another time, another place, forever.

  Prostrate in front of the container of liquid helium, Cheng Xin sobbed. Her sorrow filled the operating room, overflowed the hospital building, flooded New York City. Above her, the sorrow became a lake, then an ocean. At its bottom, she felt close to drowning.

  She didn’t know how much time passed before she felt the hand placed against her shoulders. Maybe the hand had been there for a long time, and maybe the owner of the hand had been speaking for a long time, as well.

  “There is hope.” It was the voice of an old man, gentle and slow. “There is hope.”

  Still wracked by sobs, Cheng Xin could not catch her breath, but what the voice said next got her attention.

  “Think! If they can revive that brain, what would be the ideal container for it?”

  The voice did not offer empty platitudes, but a concrete idea.

  She lifted her head, and through tear-blurred eyes, she recognized the white-haired old man: the world’s foremost brain surgeon, affiliated with Harvard Medical School. He had been the lead surgeon during the operation.

  “It would be the body that had carried this brain in the first place. Every cell in the brain contains all the genetic information necessary to reconstruct his body. They could clone him and implant the brain, and in this way, he would be whole again.”

  Cheng Xin stared at the stainless steel container. Tears rolled down her face, but she didn’t care. Then she recovered and stunned everyone: “What is he going to eat?”

  She sprinted out of the room, in as much of a rush as when she had barged in.

  * * *

  The next day, Cheng Xin returned to Wade’s office and deposited an envelope on his desk. She looked as pale as some terminally ill patients.

  “I request that these seeds be included in the Staircase capsule.”

  Wade opened the envelope and emptied its contents onto the desk: more than a dozen small packets. He ticked through them with interest: “Wheat, corn, potatoes, and these are … some vegetables, right? Hmmm, is this chili pepper?”

  Cheng Xin nodded. “One of his favorites.”

  Wade put all the packets back into the envelope and pushed it across the desk. “No.”

  “Why? These weigh only eighteen grams in total.”

  “We must make every effort to remove even point one eight grams of excess mass.”

  “Just pretend his brain is eighteen grams heavier!”

  “But it’s not, is it? Adding this weight would lead to a slower final cruising speed for the spacecraft, and delay the encounter with the Trisolaran Fleet by many years.” That cold smirk again appeared on Wade’s face. “Besides, he’s just a brain now—no mouth, no stomach. What would be the point? Don’t believe that fairy tale about cloning. They’ll just put the brain in a nice incubator and keep it alive.”

  Cheng Xin wanted to rip the cigar out of Wade’s hand and put it out against his face. But she controlled herself. “I will bypass you and make the request to those with more authority.”

  “It won’t work. Then?”

  “Then I’ll resign.”

  “I won’t allow it. You’re still useful to the PIA.”

  Cheng Xin laughed bitterly. “You can’t stop me. You’ve never been my real boss.”

  “You will not do anything I don’t allow.”

  Cheng Xin turned around and started to walk away.

  “The Staircase Program needs to send someone who knows Yun Tianming to the future.”

  Cheng Xin stopped.

  “However, that person must be a member of the PIA and under my command. Are you interested? Or do you want to hand in your resignation now?”

  Cheng Xin continued walking, but her stride slowed down. Finally, she stopped a second time. Wade’s voice came again. “You’d better be sure about your choice this time.”

  “I agree to go to the future,” Cheng Xin said. She leaned against the doorframe for support. She didn’t turn around.

  * * *

  The only time Cheng Xin got to see the Staircase spacecraft was when its radiation sail unfolded in orbit. The giant sail, twenty-five square kilometers in area, briefly reflected sunlight onto the Earth. Cheng Xin was already in Shanghai, and she saw an orange-red glowing spot appear in the pitch-black sky, gradually fading. Five minutes later, it was gone, like an eye that materialized out of nowhere to look at the Earth and then slowly shut its eyelid. The craft’s journey as it accelerated out of the Solar System was not visible to the naked eye.

  Cheng Xin was comforted by the fact that the seeds did accompany Tianming—not her seeds, exactly, but seeds that had been carefully selected by the space agricultural department.

  The giant sail’s mass was 9.3 kilograms. Four five-hundred-kilometer cables connected it to the space capsule, whose diameter was only forty-five centimeters. A layer of ablative material covered the capsule, making its launch mass 850 grams. Aft
er the acceleration leg, the capsule mass would be reduced to 510 grams.

  The acceleration leg stretched from the Earth to the orbit of Jupiter. A total of 1,004 nuclear bombs were distributed along the route, two-thirds of which were fission bombs, the rest fusion. They were like a row of mines that the Staircase craft triggered as it passed by. Numerous probes were also distributed along the route to monitor the craft’s heading and speed and coordinate minute adjustments to the positions of the remaining bombs. Like the pulses of a heart, successive nuclear detonations lit up the space behind the sail with blinding glows, and a storm of radiation propelled this feather forward. By the time the spacecraft approached Jupiter’s orbit and the 997th nuclear bomb exploded, monitoring probes showed that it had achieved 1 percent of lightspeed.

  That was when the accident occurred. Analysis of the frequency spectrum of the light reflected from the radiation sail showed that the sail had begun to curl, possibly because one of the towing cables had broken. However, the 998th nuclear bomb detonated before adjustments could be made, and the craft deviated from the projected course. As the sail continued to curl, its radar profile rapidly shrank, and it disappeared from the monitoring system. Without precise parameters for its trajectory, it would never be found again.

  As time passed, the spacecraft’s trajectory would deviate farther and farther from the projection. Hopes that it would intercept the Trisolaran Fleet diminished. Based on its approximate final heading, it should pass by another star in six thousand years and depart the Milky Way in five million years.

  At least the Staircase Program was a half success. For the first time, a man-made object had been accelerated to quasi-relativistic speeds.

  There was no real reason to send Cheng Xin to the future anymore, but the PIA still asked her to enter suspended animation. Her mission now was to act as a liaison to the Staircase Program in the future. If this pioneering effort was to be helpful to humanity’s spaceflight efforts in two centuries, someone who understood it deeply had to be there to explain the dead data and interpret the mute documents. Of course, perhaps the real reason for sending her was only one of vanity, a wish that the Staircase Program would not be forgotten by the future. Other large contemporary engineering projects had made similar efforts to send liaisons to the future for similar reasons.

  If the future wished to pass judgment on our struggles, then at least it was now possible to send someone to the future to explain the misunderstandings brought about by the passage of time.

  As Cheng Xin’s consciousness faded in the cold, she held on to a ray of comfort: Like Tianming, she would drift through an endless abyss for centuries.

  PART II

  Deterrence Era, Year 12

  Bronze Age

  It was now possible to see the Earth with the naked eye from the view window of Bronze Age. As the ship decelerated, those who weren’t on duty came to the open space at the stern to observe the Earth through the wide portholes.

  At this distance, the Earth still resembled a star, but it was possible to see a pale blue in its glow. The final deceleration stage had begun, and as the stellar drive came online, the crew, who had been floating in zero gravity, drifted toward the portholes like leaves falling in autumn, and finally landed against the broad sheets of glass. The artificial gravity generated by deceleration gradually increased until it reached 1G. The portholes now formed the floor, and the people lying down felt the weight like the embrace of Mother Earth ahead of them. Excitement echoed around the chamber.

  “We’re home!”

  “Can you believe it?”

  “I’ll get to see my kids again.”

  “We can have kids!”

  When Bronze Age left the Solar System, the law had dictated that no one could be born on the ship unless someone died.

  “She said she’d wait for me.”

  “If you’ll have her! You’re now a hero of the human race; you’ll have a flock of pretty girls after you.”

  “Oh, I haven’t seen flocks of birds in ages!”

  “Doesn’t everything we’ve been through seem like a dream?”

  “I feel like I’m dreaming now.”

  “I’m utterly terrified of space.”

  “Me too. I’m retiring as soon as we get back. I’m going to buy a farm and spend the rest of my life on solid ground.”

  * * *

  It had been fourteen years since the complete destruction of the Earth’s combined fleet. The survivors, after engaging in separate internecine battles of darkness, cut off all contact with the home planet. However, for a year and a half thereafter, Bronze Age continued to receive transmissions from Earth, most of which were surface radio communications, but which also included some transmissions intended for space.

  And then, at the beginning of November in Year 208 of the Crisis Era, all radio transmissions from Earth ceased. Every frequency fell silent, as though the Earth was a lamp that had been suddenly shut off.

  Excerpt from A Past Outside of Time

  Nyctohylophobia

  When humanity finally learned that the universe was a dark forest in which everyone hunted everyone else, the child who had once cried out for contact by the bright campfire put out the fire and shivered in the darkness. Even a spark terrified him.

  During the first few days, even mobile phone use was forbidden, and antennas around the world were forcibly shut down. Such a move, which would have once caused riots in the streets, was widely supported by the populace.

  Gradually, as reason was restored, so were the mobile networks, but severe restrictions regarding electromagnetic radiation were put in place. All radio communications had to operate at minimum power, and any violators risked being tried for crimes against humanity.

  Most people surely understood that these reactions were excessive and meaningless. The peak of the Earth’s projection of electromagnetic signals into space had occurred during the age of analog signals, when television and radio transmission towers operated at high power levels. But as digital communication became prevalent, most information was transmitted via wires and optical cables, and even radio transmissions for digital signals required far less power than analog signals. The amount of electromagnetic radiation spilling into space from the Earth had fallen so much that some pre-Crisis scholars had fretted that the Earth would become impossible to discover by friendly aliens.

  Electromagnetic waves are, moreover, the most primitive and least power-efficient method of transmitting information in the universe. Radio waves attenuate and degrade rapidly in the vastness of space, and most electromagnetic signals spilling from the Earth could not be received beyond two light-years. Only something like the transmission by Ye Wenjie, which relied on the power of the sun as an antenna, could be intercepted by listeners among the stars.

  As humanity’s technology advanced, two far more efficient methods of signaling became available: neutrinos and gravitational waves. The latter was the main method of deterrence that humanity later deployed against Trisolaris.

  The dark forest theory had a profound impact on human civilization. That child sitting by the ashes of the campfire turned from optimism to isolation and paranoia, a loner in the universe.

  Deterrence Era, Year 12

  Bronze Age

  Most of the crew aboard Bronze Age attributed the sudden cessation of all signals from the Earth to the complete conquest of the Solar System by Trisolaris. Bronze Age accelerated and headed for a star with terrestrial planets twenty-six light-years away.

  But ten days later, Bronze Age received a radio transmission from Fleet Command. The transmission had been sent simultaneously to Bronze Age and Blue Space, which was at the other end of the Solar System. The transmission gave a brief account of what had happened on Earth and notified them of the successful creation of a deterrence system to defend against Trisolaris. The two ships were ordered to return to Earth immediately. Moreover, Earth had taken great risks to send out this message to the lost ships; it would not be re
peated.

  At first, Bronze Age dared not trust this message—wasn’t it possible that it was a trap set by those who had conquered the Solar System? The warship stopped accelerating and repeatedly queried Earth for confirmation. No reply ever came, as Earth maintained radio silence.

  Just as Bronze Age was about to begin accelerating away from home again, the unimaginable happened: A sophon unfolded into low dimensions on the ship, establishing a quantum communication channel with Earth. Finally, the crew received confirmation of all that had occurred.

  The crew found that, as some of the only survivors of the holocaust suffered by the combined space forces of Earth, they were now heroes of the human race. The whole world awaited their return with bated breath. Fleet Command awarded all members of the crew with the highest military honors.

  Bronze Age began its return voyage. It was currently in outer space, about twenty-three hundred AU from the Earth, far beyond the Kuiper Belt but still some distance from the Oort Cloud. As it was cruising near maximum speed, deceleration consumed most of its fusion fuel. Its journey toward the Earth had to be conducted at a low cruising speed, and took eleven years.

  As they finally neared Earth, a small white dot appeared ahead of them and quickly grew. It was Gravity, the warship that had been dispatched to welcome Bronze Age.

  Gravity was the first stellar-class warship built after the Doomsday Battle. Deterrence-Era spaceships were no longer constructed along fixed body plans. Rather, most large spaceships were constructed out of multiple modules that could be assembled into various configurations. But Gravity was an exception. It was a white cylinder, so regular that it seemed unreal, like a basic shape dropped into space by mathematical modeling software, a platonic ideal rather than reality.

  If the crew of Bronze Age had seen the gravitational wave antennas on the Earth, they would have recognized Gravity as an almost perfect replica of them. Indeed, the entire hull of Gravity was a large gravitational wave antenna. Like its twins on the Earth’s surface, the ship was capable of broadcasting gravitational wave messages toward all corners of the universe at a moment’s notice. These gravitational wave antennas on Earth and in space comprised humanity’s dark forest deterrence system against Trisolaris.