Five Years Later

Luo Ji and his family could see the gravitational-wave antenna in the distance, but it was still another half-hour drive away. Only when they arrived did they get a real sense of its enormous size. The antenna, a horizontal cylinder a kilometer and a half long and fifty meters in diameter, was entirely suspended about two meters off the ground. Its surface was mirror-smooth, half of it reflecting the sky and half the northern China plain. It reminded people of a few things: the giant pendulums of the Three Body world, the sophons' lower-dimensional unfoldings, and the droplet. The mirrored object reflected a Trisolaran concept that humanity was still trying to figure out. In the words of a well-known Trisolaran saying, "Hiding the self through a faithful mapping of the universe is the only path into eternity."

The antenna was surrounded by a big green meadow that formed a small oasis in the desert of northern China, but this meadow had not been specially planted. Once the gravitational-wave system had been completed, it began sending continuous, unmodulated emissions that were indistinguishable from the gravitational waves emitted from supernovae, neutron stars, or black holes. The density of the gravitational beam had a peculiar effect in the atmosphere: Water vapor collected above it, so that it frequently rained in the antenna's vicinity. At times, the rain only fell within a radius of three or four kilometers, and a small, circular raincloud would hang in the air above the antenna like a giant flying saucer, leaving the brilliant sunshine in the surrounding area visible through the rain. And so this area grew lush with wild vegetation. But today, Luo Ji and his family did not witness that spectacle. Instead, they saw white clouds gather over the antenna, only to dissipate when the wind blew them away from the beam. Yet new clouds were continually forming, making the round patch of sky seem like a time wormhole to some other cloud universe. Xia Xia said that it looked like the white hair of a giant old man.

As the child ran about on the grass, Luo Ji and Zhuang Yan followed behind, until they reached the antenna. The first two gravitational-wave systems were built in Europe and North America, and employed magnetic levitation that suspended them a few centimeters from the base. But this antenna used antigravity, and could have been raised up into space if so desired. The three of them stood on the grass beneath the antenna, looking up at the huge cylinder curling up over their heads like the sky. Its large radius gave the bottom a low curvature, which meant there was no distortion in the reflected image. The setting sun now shone beneath the antenna, and, in the reflection, Luo Ji could see Zhuang Yan's long hair and white dress fluttering in the golden sunlight like an angel looking down from the sky.

He lifted up the child and she touched the antenna's smooth surface, pressing hard in one direction. "Can I make it turn?"

"If you push long enough, you can," Zhuang Yan said—then, looking at Luo Ji with a smile, asked, "Right?"

He nodded at her. "With enough time, she could move the Earth."

As had occurred so many times before, their eyes met and intertwined, a continuation of that gaze they had held in front of the Mona Lisa's smile two centuries before. They had discovered that the language of the eyes that Zhuang Yan had dreamed up was now a reality, or maybe loving humans had always possessed this language. When they looked at each other, a richness of meaning poured from their eyes just as the clouds poured from the cloud well created by the gravitational beam, endless and unceasing. But it wasn't a language of this world. It constructed a world that gave it meaning, and only in that rosy world did the words of the language find their corresponding referents. Everyone in that world was god; all had the ability to instantaneously count and remember every grain of sand in the desert; all were able to string together stars into a crystal necklace to hang around a lover's neck.…

Is this love?

The lines were displayed on a lower-dimensional unfolding of a sophon that appeared abruptly beside them. The mirrored sphere seemed like a droplet that had fallen off of some melted area on the cylinder above them. Luo Ji knew few Trisolarans and didn't know who it was who was speaking to them, or whether this one was on Trisolaris or on the fleet that was growing increasingly distant from the Solar System.

"Probably." Luo Ji nodded with a smile.

Dr. Luo, I have come in protest.

"Why?"

Because in last night's speech, you said that humanity had been so late to realize the dark forest nature of the universe not because your immature state of cultural evolution caused a lack of awareness of the universe, but because humanity has love.

"Isn't that correct?"

It's correct, though the word "love" is a little vague in the context of scientific discourse. But what you said next was incorrect. You said that humanity is probably the only species in the universe to have love, and it's this notion that supported you through the most difficult period of your Wallfacer mission.

"That's only an expression, of course. Just a nonrigorous … analogy."

I know that at least Trisolaris has love. But because it was not conducive to the civilization's overall survival, it was suppressed when it had only just germinated. Yet the seed possesses a stubborn vitality, and will still grow in certain individuals.

"May I ask who you are?"

We've never met. I was the operator who transmitted the warning to Earth two and a half centuries ago.

"My god, and you're still alive?" Zhuang Yan exclaimed.

I won't be for much longer. I've been in a dehydrated state, but over the long years, even a dehydrated body will age. However, I have seen the future I hoped to see, and for this I am happy.

"Please accept our respects," Luo Ji said.

I only wish to discuss with you one possibility: Perhaps seeds of love are present in other places in the universe. We ought to encourage them to sprout and grow.

"That's a goal worth taking risks for."

Yes, we can take risks.

"I have a dream that one day brilliant sunlight will illuminate the dark forest."

The sun was setting. Now only its tip was exposed beyond the distant mountains, as if the mountaintop was inset with a dazzling gemstone. Like the grass, the child running in the distance was bathed in the golden sunset.

The sun will set soon. Isn't your child afraid?

"Of course she's not afraid. She knows that the sun will rise again tomorrow."