Cixin Liu - The Three-Body Problem

“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?”

“The sun is the result of the large hole in the outer sphere being projected onto the inner one. The projection is so bright that it penetrates the inner sphere like the shell of an egg, and that is how we see the sun. Around the spot of light, the scattered light rays are also very bright, and can be seen through the inner shell. That is why we can see a clear sky during the day.”

“What is the force that propels the two spheres in their irregular motion?”

“It’s the force of the sea of fire outside the two spheres.”

“But the sun’s brightness and size change over time. In your double-shell model, the sun’s size and brightness ought to be fixed. Even if the brightness of the flames in the sea of fire is inconstant, the size of the hole would not be.”

“Your conception of this model is too simplistic. As conditions in the sea of fire shift and change, the two shells will expand and shrink. This leads to changes in the size and brightness of the sun.”

“What about the flying stars?”

“Flying stars? Why do you care about them? They’re not important. Maybe just some random dust flying about the inside of the universal spheres.”

“No, I think the flying stars are extremely important. Otherwise, how does your model explain the sudden extinguishing of the sun during the time of Confucius?”

“That’s a rare exception. Maybe it was because a dark spot or cloud in the sea of fire just happened to pass over the big hole in the outer shell.”

Wang pointed to the large copper sphere. “This must be your model, then?”

“Yes. I built a machine to replicate the universe. The complex gears that move the sphere simulate the forces from the sea of fire. The laws governing such motion are based on the distribution of flames in the sea of fire and the currents within it. I deduced them from hundreds of years of observations.”

“Can this sphere contract and expand?”

“Of course. Right now it’s slowly contracting.”

Wang used the handrail at the edge of the platform as a fixed visual reference. He found Mozi’s assertion to be true.

“And there’s an inner shell inside this sphere?”

“Of course. The inner shell moves within the outer shell through another complex set of mechanisms.”

“Truly a skillfully designed machine!” Wang’s praise was heartfelt. “But I don’t see a large hole in the outer shell to cast the sun’s light onto the inner shell.”

“There is no hole. On the inner surface of the outer shell I have installed a source of light to simulate the hole. The light source is made of the luminescent material gathered from hundreds of thousands of fireflies. I used a cool light because the inner shell is made of translucent plaster, which is not a good heat conductor. This way, I can avoid the problem of too much heat accumulating inside the sphere that we would have with a regular source of light. The observer can then stay inside for a long time.”

“There’s a person inside the sphere?”

“Yes. A clerk stands on top of a shelf with a wheeled base that is kept at the center of the sphere. After we set up the model universe to correspond to the current state of the real universe, the motion of the model thereafter should be an accurate simulation of the future, including the motion of the sun. After the clerk records the movements of the sun, we will have a precise calendar. This is the dream of hundreds of civilizations before us.

“And it looks like you have come at an opportune time. According to the model universe, a four-year-long Stable Era is about to begin. Emperor Wu of Han has just issued the order to rehydrate based on my prediction. Let’s wait for sunrise!”

Mozi brought up the game’s interface and slightly increased the rate of passage of game time. A red sun rose above the horizon, and the numerous frozen lakes and ponds scattered over the plain began to melt. These lakes had been covered by dust and had merged into the dun ground, but now they turned into numerous mirrors, as though the earth had opened many eyes. From up so high, Wang couldn’t see the details of rehydration, but he could see more and more people gathered on the shores of the lakes like swarms of ants coming out of their nests in spring. The world had once again been revived.

“Do you not want to join this wonderful life?” Mozi asked, pointing to the ground below. “When women are first revived, they crave love. There is no reason for you to stay here any longer. The game is over. I am the winner.”

“As a piece of machinery, your model universe is indeed incomparable. But as for its predictions…. May I use your telescope to observe something?”

“Please.” Mozi gestured at the large telescope.

Wang walked up to the instrument and paused. “How can I use it to observe the sun?”

Mozi retrieved a black, circular piece of glass. “Use this smoked glass filter.” He inserted it in front of the eyepiece.

Wang aimed the telescope at the sun, now halfway up the sky. He was impressed by Mozi’s imagination. The sun did indeed look like a hole through which a sea of fire could be seen, a small view into a much larger whole.

But as he examined the image in the telescope more closely, he realized that the sun was different from the sun he was used to in real life. The sun here had a small core. He imagined the sun as an eye. The core was like the eye’s pupil, and though it was small, it was bright and dense. The layers surrounding it, by contrast, appeared insubstantial, wispy, gaseous. The fact that he could see through the outside layers to the core indicated that those layers were transparent or translucent, and the light from those layers was likely just scattered light from the core.

The details in the image of the sun stunned Wang. He was once again assured that the game designers had hidden a vast amount of data within the superficially simple images, just waiting to be revealed by players.

As Wang pondered the meaning of the sun’s structure, he became excited. Because time in the game was now passing quickly, the sun was already in the west. Wang stood, adjusted the telescope to aim at the sun again, and tracked it until it dipped below the horizon.

Night fell, and the bonfires across the plains mirrored the sky full of stars. Wang took off the smoked glass filter and continued to scan the skies. He was most interested in the flying stars, and shortly found two. He only had time to observe one of them briefly before it was dawn again. So he inserted the filter and continued to observe the sun….

In this manner Wang performed astronomical observations for more than ten days, enjoying the thrill of discovery. Indeed, the fact that time within the game had been sped up helped with the observations, as the motion of celestial bodies became more apparent.