"And?"

"We have definitively proven that the three-body problem has no solution."

w.a.n.g gazed up at the ma.s.sive pendulum overhead. In the dawn light, it was crystal bright. Its deformed mirrorlike surface reflected everything around it like the eye of the world. In this place, in a distant age separated from the here and now by many civilizations, he and King Wen had pa.s.sed through a forest of giant pendulums on their way to the palace of King Zhou. Just like that, history had made a long circuit and returned to its starting place.

The science advisor said, "It's just like we guessed long ago: The three-body system is a chaotic system. Tiny perturbations can be endlessly amplified. Its patterns of movement essentially cannot be mathematically predicted."

w.a.n.g felt his scientific knowledge and system of thought become a blur in a single moment. In their place was unprecedented confusion. "If even an extremely simple arrangement like the three-body system is unpredictable chaos, how can we have any faith in discovering the laws of the complicated universe?"

"G.o.d is a shameless old gambler. He has abandoned us!" The speaker was Einstein, waving his violin. w.a.n.g didn't know when he had shown up.

The secretary general slowly nodded. "Yes, G.o.d is a gambler. The only hope for Trisolaran civilization is to gamble as well."

By now, the giant moon was rising again from the dark side of the horizon. Its large, silvery image was reflected by the surface of the pendulum weight. The light wriggled strangely, as though the weight and the moon had developed a mysterious sympathy together.

"This civilization seems to have developed to a very advanced state," w.a.n.g said.

"Yes. We've mastered the energy of the atom and reached the Information Age." The secretary general didn't seem to be too impressed by his own words.

"Then there is hope: Even if it's impossible to know the pattern of the suns' movements, civilization can continue to develop until it reaches a stage where it can survive the Chaotic Eras by protecting itself against the devastating catastrophes of those eras."

"People once thought as you do. That was one of the motivating forces pushing Trisolaran civilization to tenaciously come back again and again. But the moon made us realize the navete of such an idea." The secretary general pointed to the rising giant moon. "This is probably the first time you've seen this moon. Actually, since it's about a quarter of the size of our planet, it's no longer a moon, but a companion to our world in a double planet system. It resulted from the great rip."

"The great rip?"

"The disaster that destroyed the last civilization. Compared to the civilizations before it, they had ample warning of the disaster. Based on surviving records, the astronomers of Civilization 191 detected a frozen flying star early on."

w.a.n.g's heart clenched as he heard the last phrase. A frozen flying star was a terrible omen for Trisolaris. When a flying star, or a distant sun, seems to come to a complete stop against the background starfield, then the sun's and the planet's motion vectors are aligned. This has three possible interpretations: the sun and the planet are moving in the same direction at the same speed; the sun and the planet are moving apart from each other; and the sun and the planet are moving toward each other. Before Civilization 191, this last possibility was purely theoretical, a disaster that had never occurred. But the population's fear of it and their vigilance did not diminish, so much so that "frozen flying star" became an extremely unlucky phrase in many Trisolaran civilizations. A single flying star remaining still was sufficient to terrify everyone.

"And then three flying stars froze simultaneously. The people of Civilization 191 stood on the ground, gazing up helplessly at the three frozen flying stars, at the three suns falling directly toward their world. A few days later, one of the suns moved to a distance where its outer gaseous layer became visible. In the middle of a tranquil night, the star suddenly turned into a blazing sun. Separated by intervals of thirty hours or so, the other two suns also appeared in quick succession. This was not a normal kind of tri-solar day. By the time the last flying star turned into a sun, the first sun had already swept past the planet at extremely close range. Right after that, the other two suns swept past Trisolaris at even closer ranges, well within the planet's Roche limit31, such that the tidal forces imposed on Trisolaris by the three suns exceeded the force of the planet's gravitational self-attraction. The first sun shook the deepest geological structure of the planet; the second sun tore open a great rift in the planet that went straight to the core; and the third sun ripped the planet into two pieces."

The secretary general pointed at the giant moon overhead. "That's the smaller piece. There are still ruins from Civilization 191 on it, but it's a lifeless world. It was the most terrible disaster in the entire history of Trisolaris. After the planet was torn apart, the two irregularly shaped pieces each returned to spherical form under self-gravitation. The dense, searing planetary core material gushed to the surface, and the oceans boiled over the lava. The continents drifted over the magma like icebergs. As they collided, the ground became as soft as the ocean. Ma.s.sive mountain ranges tens of thousands of meters high rose in an hour and disappeared just as quickly.

"For a while, the two ripped-apart pieces were still connected by streams of molten lava that coalesced into a s.p.a.ce-spanning river. Then the lava cooled and turned into rings around the planets, but because of perturbations from the planets, the rings were unstable. The rocks that formed them fell back to the surface in a rain of giant stones that lasted several centuries.... Can you imagine what kind of h.e.l.l that was? The ecological destruction caused by this catastrophe was the most severe in all of history. All life on the companion planet went extinct, and the mother planet almost became a lifeless waste as well. But in the end, the seeds of life managed to germinate here, and as the geology of the mother planet settled down, evolution began its tottering steps in new oceans and on new continents, until civilization reappeared for the one hundred and ninety-second time. The entire process took ninety million years.

"Trisolaris's place in the universe is even more grim than we had imagined. What will happen the next time frozen flying stars occur? Very likely, our planet will not just skim past the edge of the sun, but will plunge into the fiery sea of the sun itself. Given enough time, this possibility will become certainty.

"This was originally just a frightening speculation, but a recent astronomical discovery has caused us to lose all hope for the fate of Trisolaris. The researchers had intended to recover the history of the formation of the stars and the planets based on signs in this stellar system. Instead, they discovered that, in the distant past, the Trisolaran stellar system had twelve planets. Yet, now only this one remains.

"There is only one explanation: The other eleven planets have all been consumed by the three suns! Our world is nothing more than the sole survivor of a Great Hunt. The fact that civilization has been reincarnated a hundred and ninety-two times is only a kind of luck. Also, after further study, we discovered the phenomenon of 'breathing' by the three stars."

"The stars breathe?"

"It's only a metaphor. You discovered the gaseous outer layer of the suns, but you didn't know that this gaseous layer expands and contracts over cycles lasting eons, like breathing. When the gaseous layer expands, its thickness can grow by more than a dozen times. This greatly increases the diameter of the sun, like a giant mitt that can catch planets more easily. When a planet pa.s.ses by a sun at close range, it will enter the sun's gaseous layer. Friction will cause it to lose speed, and finally, like a meteor, it will fall into the blazing sea of the sun, dragging a long, fiery tail.

"The study results show that in the long history of the Trisolaran stellar system, every time the suns' gaseous layers expanded, one or two planets were consumed. The other eleven planets all fell into a fiery sea during times when the gaseous layers were at their greatest. Right now, the gaseous layers of the three suns are in a contracted stage-otherwise our planet would have already fallen into one of them the last time they skimmed past. But scholars predict that the next expansion will occur in one thousand years."

"We can't stay in this terrible place anymore," Einstein said, crouched down on the ground like an old beggar.

The secretary general nodded. "We can't stay here any longer. The only path left for Trisolaran civilization is to gamble with the universe."

"How?" w.a.n.g asked.

"We must leave the Trisolaran stellar system and fly into the wide open sea of stars. We must find in the galaxy a new world to emigrate to."

w.a.n.g heard a grinding noise. He saw that the giant weight of the pendulum was being pulled up by a thin cable whose other end was attached to an elevated winch. As it rose to its highest point, a great waning crescent moon descended slowly in the sky behind it.

The secretary general solemnly announced, "Start the pendulum."

The elevated winch released the cable tied to the pendulum, and the weight noiselessly fell along a smooth arc. Initially, it fell slowly, but then it accelerated, reaching maximum speed at the bottom of the arc. As it sliced through the air, the sound of the wind was deep and resonant. By the time the noise disappeared, the pendulum had followed the arc to its highest point on the other side, and, after pausing for a moment, began its backward swing.

w.a.n.g felt the great force generated by the movement of the pendulum, as though the ground was shaken by its swings. Unlike a pendulum in the real world, this giant pendulum's period was not stable, but changed constantly. This was due to the continually shifting gravitational attraction of the giant moon. When the giant moon was on this side of the planet, its gravity partially canceled out the gravity of the planet, causing the pendulum to lose weight. When it was on the other side of the planet, its gravity was added to the gravity of the planet, causing the pendulum's weight to increase, almost to the level it would have had before the great rip.

As he gazed up at the awe-inspiring swings of the Trisolaran Pendulum Monument, w.a.n.g asked himself, Does it represent the yearning for order, or the surrender to chaos? w.a.n.g also thought of the pendulum as a gigantic metal fist, swinging eternally against the unfeeling universe, noiselessly shouting out Trisolaran civilization's indomitable battle cry....

As w.a.n.g Miao's eyes blurred with tears, he saw a line of text appear against the background of the swinging pendulum: Four hundred and fifty-one years later, Civilization 192 was destroyed by the fiery flames of twin suns appearing together. It had reached the Atomic Age and the Information Age.

Civilization 192 was a milestone in Trisolaran civilization. It finally proved that the three-body problem had no solution. It gave up the useless effort that had already lasted through 191 cycles and set the course for future civilizations. Thus, the goal of Three Body has changed.

The new goal is: Head for the stars; find a new home.

We invite you to log on again.

After logging out of Three Body, w.a.n.g felt exhausted, the same way he did after each previous session. But this time, he only rested half an hour before logging in again.

This time, against the pitch-black background, an unexpected line of text appeared: The situation is urgent. The Three Body servers are about to be shut down. Please log on freely during the remaining time. Three Body will now go directly to the final scene.

20.

Three Body: Expedition The chilly dawn revealed a bare landscape. There was no pyramid, no United Nations Headquarters, no sign of the Pendulum Monument. Only a dark desert extended to the horizon, just as w.a.n.g had seen the first time he had logged in.

But w.a.n.g soon realized that he was wrong. What he thought were numerous stones arrayed across the desert were not stones at all, but human heads. The ground was filled with a densely packed crowd.

From where he stood on a small hill, w.a.n.g could see no end to the sea of people. He estimated the number of individuals within his view alone to be in the hundreds of millions. All the Trisolarans on the planet were probably gathered here.

The silence of hundreds of millions created a suffocating sense of strangeness. What are they waiting for? w.a.n.g looked around and noticed everyone was gazing up at the sky.

w.a.n.g lifted his face and found the starry sky had been transformed to an astonishing sight: The stars were arrayed in a square formation! However, w.a.n.g soon realized that the stars in the formation were in a synchronous...o...b..t above the planet, moving together against the dimmer, more distant background of the Milky Way.

The stars in the formation closest to the direction of dawn were also the brightest, shining with a silver light that cast shadows on the ground. The brightness decreased as one moved away from that edge. w.a.n.g counted more than thirty stars along each edge of the formation, which meant a total of more than a thousand stars. The slow movement of the obviously artificial formation against the starry universe exuded a solemn power.

A man standing next to him nudged him lightly and spoke in a low voice, "Ah, Great Copernicus, why have you come so late? Three cycles of civilizations have pa.s.sed, and you've missed many great enterprises."

"What is that?" w.a.n.g asked, pointing at the formation in the sky.

"The Trisolaran Interstellar Fleet. It's about to begin its expedition."

"Trisolaran civilization has already achieved the capacity for interstellar flight?"

"Yes. All those magnificent ships can reach one-tenth the speed of light."

"That is a great accomplishment, as far as I understand it, but it still seems too slow for interstellar flight."

"The journey of a thousand miles begins with the first step. The key is finding the right target."

"What's the fleet's destination?"

"A star with planets about four light-years away-the closest star to the Trisolaran system."

w.a.n.g was surprised. "The closest star to us is also about four light-years away."

"You?"

"The Earth."

"Oh, that's not very surprising. In most regions of the Milky Way, the distribution of stars is fairly even. It's the result of star cl.u.s.ters acting under the influence of gravity. The distance between most stars is between three and six light-years."

A loud, joyous cry erupted from the crowd. w.a.n.g looked up and saw that every star in the square formation was rapidly growing brighter. This was due to the light emitted by the ships themselves. Their combined illumination soon overwhelmed the dawn, and one thousand stars became one thousand little suns. Trisolaris was bathed in glorious daylight, and the crowd raised their hands and formed an endless prairie of uplifted arms.

The Trisolaran Fleet began to accelerate, solemnly gliding across the dome of the sky, skimming past the giant, just-risen moon's tip, casting a dim blue glow against the moon's mountains and plains.

The joyous cry subsided. The people of Trisolaris mutely gazed as their hope gradually shrunk in the western sky. They would not know the outcome of the launch in their lifetimes, but four or five hundred years from now, their descendants would receive the news from a new world, the beginning of a new life for Trisolaran civilization. w.a.n.g stood with them, silently gazing, until the phalanx of a thousand stars shrank into a single star, and until that star disappeared in the western night sky. Then the following text appeared: The Trisolaran Expedition to the new world has begun. The fleet is still in flight....

Three Body is over. When you have returned to the real world, if you remain true to the promise you've made, please attend the meet-up of the Earth-Trisolaris Organization. The address will be in the follow-up e-mail you receive.

PART III.

SUNSET FOR HUMANITY.

21.

Rebels of Earth There were many more attendees this time than at the last Three Body meet-up. They met at the employee cafeteria of a chemical plant. The factory had already been moved elsewhere, and the interior of the building, which was about to be demolished, was worn out but s.p.a.cious. About three hundred people were gathered here, and w.a.n.g Miao noticed many familiar faces: celebrities and elites of various fields; famous scientists, writers, politicians, and so on.

The first thing to attract w.a.n.g's attention was the strange device at the center of the cafeteria. Three silver spheres, each slightly smaller than a bowling ball, hovered and swirled over a metal base. w.a.n.g guessed the device was probably based on magnetic levitation. The orbits of the three spheres were completely random: a real-life version of the three-body problem.

The others didn't pay much mind to the artistic portrayal of the three-body problem. Instead, they focused on Pan Han, who was standing on top of a broken table in the middle of the cafeteria.

"Did you murder comrade Shen Yufei?" a man asked.

"Yes," Pan said, perfectly calm. "It's because the Adventists have traitors like her in our midst that the Organization faces the crisis it does today."

"Who gave you the right to kill?"

"I did it out of a sense of duty to the Organization."

"Duty? I think you've always had malice in your heart!"

"What do you mean by that?"

"What has the Environment Branch done under your leadership? Your charge is to exploit and create environmental problems to make the population loathe science and modern industry. But in reality, you've only used our Lord's technology and predictions to gain riches and fame for yourself!"

"Do you think I became famous for myself? To my eyes, the entire human race is a pile of garbage. Why would I care what they think? But if I'm not famous, how do I direct and channel their thinking?"

"You always pick the easy tasks. What you've done could have been better accomplished by regular environmentalists. They're more sincere and pa.s.sionate than you, and with just a little guidance, we could easily take advantage of their actions. Your Environment Branch should be creating environmental disasters and then exploiting them. For example, disseminating poison in reservoirs, leaking toxic waste from chemical plants ... have you done any of those? No, not a single one!"

"We had devised numerous programs and plans, but the commander vetoed them all. Anyway, such acts would have been stupid, at least until recently. The Biology and Medicine Branch once created a catastrophe from the overuse of antibiotics, but that was soon detected. And the rash actions of the European Detachment almost drew attention to us."

"Talk about drawing attention to us-you just murdered someone!"

"Listen to me, comrades! Sooner or later, it would have been unavoidable. You must already know that the governments of the world are preparing for war. In Europe and North America, they're already cracking down on the Organization. Once the crackdown begins here, the Redemptionists will no doubt side with the government. So our first priority is to purge the Redemptionists from the Organization."

"That is not within your authority."

"Of course the commander must decide. But, comrades, I can tell you right now that the commander is an Adventist!"

"Now you're just making things up. Everyone knows the scope of the commander's power. If the commander really is an Adventist, then the Redemptionists would have been purged long ago."

"Maybe the commander knows something we don't. Perhaps that's what the meeting today is about."

After this, the crowd's attention turned away from Pan Han to the crisis before them. A famous scientist who had won the Turing Award jumped onto the table and began to speak. "The time for talk is over. Comrades, what should be our next step?"

"Start a global rebellion!"

"Then we're asking to be killed."

"Long live the spirit of Trisolaris! We shall persevere like the stubborn gra.s.s that resprouts after every wildfire!"

"A rebellion will finally reveal our existence to the world. As long as we have an appropriate plan of action, I'm sure many people will support us."

This last remark came from Pan Han, and many applauded.