Death's End (Remembrance of Earth’s Past, #3)

by Liu Cixin

“Yun Tianming once gave you a star, and now he’s given you a universe. Cheng Xin, this is an entire universe. It might be small, but it’s a complete universe.”

Sophon bowed deeply to Cheng Xin and Guan Yifan. When she straightened, she smiled at Cheng Xin. “I said that the universe is grand, but life is grander. Fate has indeed directed us to meet again.”

Mr. Yun hoped that you could hide in this tiny universe and avoid the collapse of the great universe—or the big crunch—and, after the next big bang, enter the new universe and see its Edenic Age. Right now, we exist in an independent timeline. Time is passing rapidly in the great universe, and you will certainly be able to see its end within your lifetimes. More specifically, I estimate that the great universe will collapse into a singularity after about ten years here.” “If a new big bang occurs, how will we know?” asked Yifan. “We’ll know. We can sense the conditions in the great universe through the supermembrane.”

Cheng Xin said, “I also want to go to the new universe. The singularity and the new big bang will erase all memories of our universe. I want to bring some memory of humanity there.” Sophon nodded solemnly at Cheng Xin. “That is a great task you’ve set yourself. There are others doing similar work, but you’re the first human from the Solar System to do this.”

His voice still echoed in her ears: We’re going to advance! Advance! We’ll stop at nothing to advance!

She explained that all the universes were bubbles above a supermembrane—this was a fundamental conceptual image from Trisolaran physics and cosmology, and she could explain it no further.

the monitoring systems in Universe 647 often received messages from other great universes on the supermembrane. Some were natural phenomena; some were messages from intelligent beings that could not be decoded—but they had never received any message from the particular great universe they had come from.

Cheng Xin began to write her memoir so that she could record the history she knew. She named the book A Past Outside of Time.

Out of the many macro dimensions, it was likely that more than one dimension would belong to time. “Multi-dimensional time?” Cheng Xin couldn’t understand the concept at first. “Even if time were only two-dimensional, it would be a plane instead of a line,” Yifan explained. “There would be an infinite number of directions, and we could simultaneously make countless choices.” “And at least one of those choices would turn out to be right,” added Sophon.

She also mentioned that there was a group of intelligent beings in the universe that resembled the Zero-Homers, but they called themselves the Returners. They advocated against the construction of mini-universes, and called for the mass in completed mini-universes to be returned to the great universe.… But she didn’t know much else about them.

After 1.57 million languages, the broadcast finished. The window now showed only the message written in Trisolaran and Earth languages. Cheng Xin and Guan Yifan couldn’t even read the message because tears blurred their eyes.

A notice from the Returners: The total mass of our universe has decreased to below the critical threshold. The universe will turn from being closed to open, and die a slow death in perpetual expansion. All lives and all memories will also die. Please return the mass you have taken away and send only memories to the new universe.

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.

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.

The ultimate fate of all intelligent beings has always been to become as grand as their thoughts.