The Three-Body Problem

“Ah, I know you!” Mozi grew excited. “You were a follower of King Wen back in Civilization Number 137.”

“I did follow him here. But I never believed his theories.”

“You’re right.” Mozi nodded at Wang solemnly. Then he moved closer. “During the three hundred and sixty-two thousand years you’ve been away, civilization has been reborn four more times. These civilizations struggled to develop through the irregular alternation of Chaotic Eras and Stable Eras. The shortest-lived one got only halfway through the Stone Age, but Civilization Number 139 broke a record and developed all the way to the Steam Age.”

“You’re saying that people from that civilization found the laws governing the sun’s motion?”

Mozi laughed and shook his head. “Not at all. They were just lucky.”

“But the effort to do so has never ceased?”

“Of course not. Come, let us see the efforts of the last civilization.” Mozi led Wang to a corner of the observatory platform. The ground spread out beneath them like an ancient piece of leather. Mozi aimed one of the smaller telescopes at a target on the ground and gestured for Wang to look. Wang looked through the eyepiece and saw a strange sight: a skeleton. In the dawn light it gave off a snow-white glint and appeared to be very refined.

Astonishingly, the skeleton stood on its own. Its posture was graceful and elegant. One hand was held below the chin, as though stroking a long-missing beard. Its head tilted slightly up, as though questioning sky and earth.

“That’s Confucius,” Mozi said. “He believed that everything had to fit li, the Confucian conception of order and propriety, and nothing in the universe could be exempt from it. He created a system of rites and hoped to predict the motion of the sun with it.”

“I can imagine the result.”

“Right you are. He calculated how the sun would follow the rites, and predicted a five-year Stable Era. And you know what? There was indeed a Stable Era … lasting a month.”

“And then one day the sun just didn’t come out?”

“No, the sun rose that day as well. It rose to the middle of the sky, and then went out.”

“What? Went out?”

“Yes. It gradually dimmed, became smaller, and then went out all of a sudden. Night fell. Oh, the cold. Confucius stood there and froze into a column of ice. And there he remains.”

“Was there anything remaining in the sky after the sun went out?”

“A flying star appeared in that location, like a soul left behind after the sun died.”

“You’re sure that the sun really disappeared suddenly, and the flying star appeared just as suddenly?”

“Yes, absolutely. You can check the historical annals. It was clearly recorded.”

“Hmmm…” Wang thought hard about this information. He had already formed some vague ideas about the workings of the world of Three Body. But this bit of news from Mozi overturned all his theories. “How can it be … sudden?” he muttered in annoyance.

“We’re now in the Han Dynasty—I’m not sure if it’s the Western Han or the Eastern Han.”

“You’ve stayed alive until now?”

“I have a mission: observing the precise movements of the sun. Those shamans, metaphysicians, and Daoists are all useless. Like those proverbial bookish men who could not even tell types of grains apart, they do not labor with their hands, and know nothing practical. They have no ability to do experiments, and they’re immersed in their mysticism all day long. But I’m different. I know how to make things.” He pointed to the numerous instruments on the platform.

“Do you think these can lead you to your goal?” Wang nodded specifically at the giant copper sphere.

“I have theories, too, but they’re not mystical. They’re derived from a large number of observations. First, do you know what the universe is? It’s a machine.”

“That’s not very insightful.”

“Let me be more specific: The universe is a hollow sphere floating in the middle of a sea of fire. There are numerous tiny holes in the surface of the sphere, as well as a large one. The light from the sea of flames shines through these holes. The tiny ones are stars, and the large one is the sun.”

“That’s a very interesting model.” Wang looked at the giant copper sphere again and guessed at its purpose. “But there’s a problem with your theory. When the sun rises or sets, we can see its motion against the background of fixed stars. But in your hollow sphere, all the holes remain in fixed positions relative to each other.”

“Correct! That’s why I’ve modified my model. The universal sphere is made of two spheres, one inside the other. The sky we can see is the surface of the inner sphere. The outer sphere has one large hole while the inner sphere has many small holes. The light coming through the hole in the outer sphere is reflected and scattered many times in the space between the two spheres, filling it with light. Then the light comes in through the tiny holes in the inner sphere, and that’s how we see the stars.”

“What about the sun?”