Death's End

Cheng Xin and Guan Yifan locked gazes. In each other’s eyes, they saw the dark future for the great universe. In perpetual expansion, all the galaxies would move farther away from each other until none were visible from any other. By then, standing at any point in the universe, all one would see was darkness in every direction. The stars would go out one by one, and all celestial bodies would turn into thin dust clouds. Coldness and darkness would reign over all, and the universe would become a vast, empty tomb. All civilizations and all memories would be buried in that endless tomb for eternity. Death would be eternal.

The only way to prevent this future was to return the matter locked up in all the mini-universes constructed by all the civilizations. But such a decision meant that the mini-universes would not survive, and all the refugees in the mini-universes had to return to the great universe. That was the meaning of the name of the Returners’ movement.

The two said everything they needed to say to each other with their eyes and made their decision wordlessly. But Cheng Xin still spoke aloud. “I want to go back. But if you want to stay here, I’ll stay with you.”

Yifan shook his head slowly. “I study a grand universe whose diameter is sixteen billion light-years. I don’t want to spend the rest of my life in this universe that’s only a kilometer in each direction. Let’s go back.”

“I must advise against that,” said Sophon. “We can’t precisely determine how fast time is passing in the great universe, but I can be certain that at least ten billion years have passed there since the time you came here. Planet Blue has long since vanished, and the star Mr. Yun gave you was extinguished a long time ago. We know nothing of the conditions in the great universe, and it’s possible that it’s not even three-dimensional anymore.”

“I thought you could move the exit of the mini-universe at lightspeed,” Yifan said. “Can’t you move it around to find a habitable location?”

“If you insist, I will try. But I still think staying here is the best choice. There are two possible futures if you remain: If the Returners succeed in their mission, the great universe will collapse into a singularity and lead to a new big bang so that we can go to the new universe. But if the Returners fail and the great universe dies, you can live out the rest of your lives in this mini-universe. This isn’t too bad.”

“If everyone in every mini-universe thinks that way,” said Cheng Xin, “then they will have doomed the great universe.”

Sophon gazed at Cheng Xin wordlessly. Given the speed of Sophon’s thought, perhaps this period of time felt as long as several centuries to her. It was hard to imagine that software and algorithms could produce such a complex expression. Perhaps Sophon’s AI software had brought up all the memories accumulated across almost twenty million years since she had met Cheng Xin. All these memories seemed to precipitate in her gaze: sorrow, admiration, surprise, reproach, regret… so many complicated feelings mixed together.

“You’re still living for your responsibility,” Sophon said.

Excerpt from A Past Outside of Time The Stairs of Responsibility

All my life has been spent climbing up a flight of stairs made of responsibility.

When I was little, my only duty was to study hard and obey my parents.

Later, in high school and college, the responsibility to study hard continued, but there was also the added obligation to make myself useful rather than a drain on society.

By the time I started to work toward my doctorate, my responsibilities became more concrete. I needed to contribute to the development of chemical rockets, to build more powerful, more reliable rockets so that more materials and a few men and women could be sent into Earth orbit.

Later, I joined the PIA, and my responsibility was to send a probe into space a light-year away to meet the invading Trisolaran Fleet. This was a distance about ten billion times greater than the distance I had worked with as a rocket engineer.

And then, I received a star. During the new era, it brought me previously unimaginable responsibilities. I became the Swordholder, whose duty was to maintain dark forest deterrence. Looking back on it now, perhaps it was a bit of an exaggeration to claim that I held the fate of humankind; but I really did control the direction of development for two civilizations.

Later, my responsibilities became more complicated: I wanted to endow humans with lightspeed wings, but I also had to thwart that goal to prevent a war.

I don’t know how much those catastrophes and the final destruction of the Solar System had to do with me. Those are questions that could never be answered definitively. But I’m certain they had something to do with me, with my responsibilities.