The Dark Forest

by Liu Cixin

  “No, it’s not simple at all. It’s like recording the relative position of every grain of sand in the desert.”

  “Even harder than that. The Milky Way, unlike the desert, is in motion, and the relative positions of its stars are constantly changing. The later the position information is received, the greater the error caused by these changes. This means the database has to be able to predict the changes in position of each of those hundred billion stars. In theory, it’s not a problem, but to actually do it … God…”

  “Would it be hard for us to send that positional information?”

  “No, because we would only need to have a position pattern for a limited number of stars. And now that I’ve had time to think about it, given the average stellar density of the outer arm of the galaxy, a position pattern with no more than thirty stars should be sufficient. That’s a small amount of information.”

  “Good. Now I’ll ask a third question: Outside the Solar System, there are other stars with planets. You’ve discovered several hundred, right?”

  “More than a thousand to date.”

  “And the closest to the sun?”

  “244J2E1, sixteen light-years from the sun.”

  “As I remember it, the serial numbers are set like this: the prefix digits represent the order of discovery; the letters J, E, and X stand for Jupiter-type planets, Earth-type planets, and other planets, respectively; and the digits following the letter indicate the number of that type of planet in the system.”

  “That’s right. 244J2E1 is a star with three planets, two of them Jupiter-type and one Earth-type.”

  Luo Ji thought for a moment, then shook his head. “That’s too close. How about a little farther, like … around fifty light-years?”

  “187J3X1, 49.5 light-years from the sun.”

  “That one’s fine. Can you draw up a position pattern for that star?”

  “Of course I can.”

  “How long would it take? Would you need help?”

  “I can do it here if there’s a computer with Internet. For a pattern of, say, thirty stars, I can give it to you tonight.”

  “What time is it now? It’s not nighttime already?”

  “I’d say it’s probably morning, Dr. Luo.”

  Ringier went to the computer room next door, and Luo Ji called in Kent and Zhang Xiang. He first explained to Kent that he wanted the PDC to hold the next Wallfacer hearing as soon as possible.

  Kent said, “There are lots of PDC meetings these days. Once you’ve submitted the application, you’ll probably only have to wait a few days.”

  “Then I’ll have to wait. But I’d really like it as soon as possible. Also, I have a request: to attend the hearing here via video rather than go to the UN.”

  Kent looked reluctant. “Dr. Luo, don’t you think that’s a little inappropriate? For such a high-level international meeting … It’s a question of respect for the participants.”

  “It’s part of the plan. All those bizarre requests I made in the past were fulfilled, but this one’s over the line?”

  “You know…” Kent faltered.

  “I know that a Wallfacer’s status isn’t like it once was, but I insist on this.” When he continued, it was in a softer voice, even though he knew that the sophons hanging in the vicinity could still hear. “There are two possibilities now: One, if everything is like it used to be, I wouldn’t mind going to the UN. But there’s another possibility: I may be in a very dangerous situation, and I can’t take that risk.”

  Then he said to Zhang Xiang, “That’s why I’ve brought you here. We may become a target for a concentrated enemy attack, so security must be strengthened.”

  “Don’t worry, Dr. Luo. We’re located two hundred meters below ground. The area above us is under lockdown, an antimissile system has been deployed, and a state-of-the-art subterranean warning system has been installed to detect the digging of a tunnel from any direction. I guarantee to you that our security is foolproof.”

  When the two men left, Luo Ji took a walk down the hallway, his thoughts turning involuntarily to the Garden of Eden (he knew its name now, but still called it that in his heart) and its lake and snow peak. He knew that it was quite likely he would spend the rest of his life underground.

  He looked around at the sunlamps in the hallway ceiling. The light they emitted was nothing like the sun.

  * * *

  Two meteors moved slowly across the starfield. All was dark on the ground, and the distant horizon blended into one with the night sky. A burst of whispers sounded through the dark, although the speakers remained unseen, as if the voices themselves were invisible creatures floating in the darkness.

  With a clink, a small flame appeared in the darkness, its dim light revealing three faces: Qin Shi Huang, Aristotle, and Von Neumann. The flame came from a lighter in Aristotle’s hand. When a few torches were extended, he lit one, which then passed fire among the others to form a shaky light in the wilderness and illuminate a group of people drawn from every era. Their whispers continued.

  Qin Shi Huang leapt up on a stone and brandished his sword, and the crowd fell silent.

  “The Lord has issued a new command: Destroy Wallfacer Luo Ji,” he said.

  “We too have received this command. This is the second assassination order that the Lord has issued for Luo Ji,” Mozi said.

  “But it will be difficult to kill him now,” someone said.

  “Difficult? It’s impossible!”

  “If Evans hadn’t added that condition to the first assassination order, he would have been dead five years ago.”

  “Perhaps Evans was right to do so. After all, we don’t know his reasons. Luo Ji was lucky to escape a second time in the UN Plaza.”

  Qin Shi Huang stopped the debate with a wave of his sword. “Shall we talk instead about what to do?”

  “There’s nothing we can do. Who can even get anywhere near a bunker two hundred meters deep, much less get inside? It’s guarded too tightly.”

  “Shall we consider nuclear weapons?”

  “The place is an antinuke bunker from the Cold War, damn it.”

  “The only viable option is sending someone to infiltrate security.”

  “Can that be done? We’ve had years. Has there ever been a successful infiltration?”

  “Infiltrate his kitchen!” This prompted some laughter.

  “Cut the crap. The Lord ought to tell us the truth, and maybe we can come up with a better option.”

  Qin Shi Huang answered the last speaker: “I also made that request, but the Lord said the truth was the most important secret in the universe and could not be revealed. The Lord spoke of it with Evans under the impression that humanity already knew but later learned otherwise.”

  “Then ask the Lord to transfer technology!”

  Many other voices echoed this. Qin Shi Huang said, “This was another request I made. To my surprise, the Lord uncharacteristically did not reject it entirely.”

  A commotion took hold of the crowd, but Qin Shi Huang’s next words quieted the excitement: “But once the Lord learned the location of the target, the request was swiftly rejected. It said that as far as the target’s location was concerned, any technology It could transfer to us would be ineffective.”

  “Is he really that important?” Von Neumann asked, unable to conceal a note of jealousy in his voice. As the first successful Wallbreaker, he had risen rapidly in the organization.

  “The Lord is afraid of him.”

  Einstein said, “I have thought this over for a long time, and I believe that the Lord’s fear of Luo Ji has only one possible reason: He is the mouthpiece of certain power.”

  Qin Shi Huang shut down further discussion of the subject: “Don’t get into that. Instead, let’s think of how to fulfill the Lord’s command.”

  “It can’t be done.”

  “It really can’t be done. It’s a mission that can’t be completed.”

  Qin Shi Huang clanged his sword on the rock be
neath his feet. “This mission is crucial. The Lord may really be under threat. Besides, if we complete it, the organization will be greatly elevated in the Lord’s eyes! Gathered here are the elite of every sphere throughout the world, so how can we fail to think of something? Go back and think it over, and send your plans here to me through other channels. We’ve got to get on this!”

  The torches burned out in succession and darkness swallowed everything. But the whispering went on.

  * * *

  The PDC Wallfacer Project Hearing did not convene for two weeks. After Tyler’s failure and the hibernation of the other two Wallfacers, the PDC’s main priority and attention had turned to mainstream defense.

  Luo Ji and Kent awaited the start of the meeting in the videoconference room. The conference video connection had been made, and the big screen displayed the PDC auditorium, where the circular table familiar from the Security Council days was still completely empty. Luo Ji had arrived early as something of an apology for not attending in person.

  While they waited, he chatted with Kent and asked him how he was managing. Kent said that he had lived in China for three years when he was younger, so he was quite accustomed to it and was doing well. At any rate, he didn’t have to spend all day underground like Luo Ji, and his rusty Chinese had recently regained its fluency.

  “You sound like you have a cold,” Luo Ji said.

  “I’ve just caught the bed flu,” he replied.

  “Bird flu?” Luo Ji said in alarm.

  “No. Bed flu. That’s what the media’s calling it. It started going around in a nearby city a week ago. It’s infectious, but symptoms are light. There’s no fever, just a runny nose, and some patients get a sore throat. There’s no need for medication, and it goes away on its own in three days or so after a little bed rest.”

  “The flu is usually more serious than that.”

  “Not this time. A lot of soldiers and staff here have already been infected. Haven’t you noticed that they replaced the caretaker? She caught the bed flu too, but was afraid of giving it to you. But as your liaison, I can’t be replaced for the time being.”

  Onscreen the national delegates had begun to enter the auditorium. They sat down and started talking in low voices, as if they hadn’t noticed Luo Ji’s presence. The incumbent rotating chair of the PDC opened the meeting, saying, “Wallfacer Luo Ji, the Wallfacer Act was amended at the special session of the UN General Assembly that just adjourned. You’ve seen it?”

  “Yes,” he answered.

  “Then you must have noticed that the Act strengthens the examinations and restrictions on Wallfacer resource allocation. I hope that the plan you will submit to the hearing today will comply with the Act’s requirements.”

  “Mr. Chair,” Luo Ji said, “the other three Wallfacers have allocated an enormous amount of resources to the execution of their own strategic plans. To limit my plan’s resources in this way is unfair.”

  “Resource allocation privileges depend on the plan itself, and you must be aware that the other three Wallfacer plans are not in conflict with mainstream defense. In other words, the research and engineering they are conducting would have been carried out even without the Wallfacer Project. I hope that your strategic plan is also of this nature.”

  “I’m sorry to say that my plan is not of this nature. It has absolutely nothing to do with mainstream defense.”

  “Then I’m sorry, too. Under the new Act, the resources you can allocate to this plan are very limited.”

  “Even under the old plan, I couldn’t allocate all that much. However, this isn’t a problem, Mr. Chair. My strategic plan consumes practically no resources at all.”

  “Just like your previous plans?”

  The chair’s remark prompted snickers from several participants.

  “Even less than in the past. Like I said, it consumes practically no resources at all,” he said simply.

  “Then let’s have a look,” the chair said, nodding.

  “The specifics of the plan will be introduced by Dr. Albert Ringier, although I presume you all received the corresponding file. To sum up, using the radio wave magnification capabilities of the sun, a message will be sent into the cosmos containing three simple images, along with additional information to demonstrate that these images have been sent by an intelligence as opposed to occurring naturally. The images are included in the file.”

  The sound of rustling paper filled the auditorium as the attendees located the three sheets. The images were also displayed on the screen. They were quite simple. Each consisted of black dots, seemingly scattered at random, but they all noticed that each image contained one conspicuously larger dot that was marked with an arrow.

  “What is it?” asked the US representative, who, like the rest of the attendees, was inspecting the images carefully.

  “Wallfacer Luo Ji, according to the basic principles of the Wallfacer Project, you do not need to answer that question,” the chair said.

  “It’s a spell,” he said.

  The rustling and murmuring in the auditorium stopped abruptly. Everyone looked up in the same direction, so that Luo Ji now knew the location of the screen displaying his feed.

  “What?” asked the chair, with narrowed eyes.

  “He said it’s a spell,” someone seated at the circular table said loudly.

  “A spell against whom?”

  Luo Ji answered, “Against the planets of star 187J3X1. Of course, it could also work directly against the star itself.”

  “What effect will it have?”

  “That’s unknown right now. But one thing is certain: The effect of the spell will be catastrophic.”

  “Er, is there a chance these planets have life?”

  “I consulted repeatedly with the astronomical community on that point. From present observational data, the answer is no,” Luo Ji said, narrowing his eyes like the chair had. He prayed silently, May they be right.

  “After the spell is sent out, how long will it take to work?”

  “The star is around fifty light-years from the sun, so the spell will be complete in fifty years at the earliest. But we won’t be able to observe its effects for one hundred years. This is just the earliest estimate, however. The actual time it takes might stretch out much farther.”

  After a moment of silence in the auditorium, the US representative was the first to move, tossing the three sheets and their printed black dots onto the table. “Excellent. We finally have a god.”

  “A god hiding in a cellar,” added the UK representative, to peals of laughter.

  “More like a sorcerer,” sniffed the representative of Japan, which had never been admitted to the Security Council, but had been accepted immediately once the PDC was established.

  “Dr. Luo, you have succeeded in making your plan weird and baffling, at least,” said Garanin, the Russian representative who had held the rotating chair on several occasions during Luo Ji’s five years as a Wallfacer.

  The chair banged the gavel, silencing the commotion in the auditorium. “Wallfacer Luo Ji, I have a question for you. Given that this is a spell, why don’t you direct it at the enemy’s world?”

  Luo Ji said, “This is a proof of concept. Its actual implementation will wait for the Doomsday Battle.”

  “Can’t Trisolaris be used as the test target?”

  Luo Ji shook his head with finality. “Absolutely not. It’s too close. It’s close enough that the effects of the spell might reach us. That’s why I rejected any planetary star system within fifty light-years.”

  “One final question: Over the next hundred or more years, what do you plan on doing?”

  “You’ll be free of me. Hibernation. Wake me when the effects of the spell on 187J3X1 are detected.”

  * * *

  As he was preparing for hibernation, Luo Ji came down with the bed flu. His initial symptoms were no different from everyone else, just a runny nose and a slight throat inflammation, and neither he nor anyone else paid it
any attention. But two days later his condition worsened and he began to run a fever. The doctor found this abnormal and took a blood sample back to the city for analysis.

  Luo Ji spent the night in a fevered torpor, haunted endlessly by restless dreams in which the stars in the night sky swirled and danced like grains of sand on the skin of a drum. He was even aware of the gravitational interaction between these stars: It wasn’t three-body motion, but the 200-billion-body motion of all of the stars in the galaxy! Then the swirling stars clustered into an enormous vortex, and in that mad spiral the vortex transformed again into a giant serpent formed from the congealed silver of every star, which drilled into his brain with a roar.…

  At around four in the morning, Zhang Xiang was awakened by his phone. It was a call from the Planetary Defense Council Security Department leadership who, in severe tones, demanded that he report immediately on Luo Ji’s condition, and ordered the base to be put under a state of emergency. A team of experts was on its way over.

  As soon as he hung up the phone, it rang again, this time with a call from the doctor in the tenth basement, who reported that the patient’s condition had sharply deteriorated and he was now in a state of shock. Zhang Xiang descended the elevator at once, and the panicked doctor and nurse informed him that Luo Ji had begun spitting up blood in the middle of the night and then had gone unconscious. Zhang Xiang saw Luo Ji lying on the bed with a pale face, purple lips, and practically no signs of life in his body.

  The team, consisting of experts from the Chinese Center for Disease Control and Prevention, doctors from the general hospital of the PLA, and an entire research team from the Academy of Military Medical Sciences soon arrived.

  As they observed Luo Ji’s condition, one expert from the AMMS took Zhang Xiang and Kent outside and described the situation to them. “This flu came to our attention a while ago. We felt that its origin and characteristics were highly abnormal, and it’s clear now that it’s a genetic weapon, a genetic guided missile.”

  “A guided missile?”

  “It’s a genetically altered virus that is highly infectious, but only causes mild flu symptoms in most people. However, the virus has a recognition ability which allows it to identify the genetic characteristics of a particular individual. Once the target has been infected, it creates deadly toxins in his blood. We now know who the target is.”