Cixin Liu - The Three-Body Problem

“A tombstone? For who?”

“For an aspiration, a striving that lasted through almost two hundred civilizations: the effort to solve the three-body problem, to find the pattern in the suns’ movements.”

“Is the effort over?”

“Yes. As of now, it’s completely over.”

Wang hesitated for a moment before taking out a stack of papers, Wei Cheng’s three-body mathematical model. “I… I came here for this. I brought a mathematical model that solves the three-body problem. I have reason to believe it will likely work.”

As soon as Wang said this, the crowd around him lost interest. They returned to their cliques to continue their conversations. He noticed that a few even shook their heads and laughed as they left him. The secretary general took the document and, without even glancing at it, handed it to a slender man wearing glasses standing next to him. “Out of respect for your famed reputation, I’ll have my science advisor take a look. Indeed, everyone here has shown you respect. If anyone else had said what you said, they’d be laughing at him.”

The science advisor flipped through the document. “Evolutionary algorithm? Copernicus, you’re a genius. Anyone who can come up with such an algorithm is a genius. This requires not only superior math skills, but also imagination.”

“You seem to be suggesting that someone has already created such a mathematical model?”

“Yes. There are dozens of other mathematical models. Of those, more than half are more advanced than yours. They’ve all been implemented and run on computers. During the past two centuries, such massive computation became the principal activity of this world. Everyone waited for the results as if waiting for Judgment Day.”

“And?”

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

Wang gazed up at the massive 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 passed 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.”

Wang 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?”

“God is a shameless old gambler. He has abandoned us!” The speaker was Einstein, waving his violin. Wang didn’t know when he had shown up.

The secretary general slowly nodded. “Yes, God 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,” Wang 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 naïveté 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.”

Wang’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 limit, [31] Author’s Note: Roche limit: Édouard Roche, French astronomer, was the first to calculate the theoretical distance between two celestial bodies such that the smaller body will be torn apart by tidal forces from the larger body. The Roche limit is usually expressed as a function of the densities of the bodies and the equatorial radius of the larger body. 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. Massive 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 space-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 hell 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.