Death's End

Cheng Xin rode the elevator to the surface. Exiting the elevator station, she saw the plaza where the deterrence handover ceremony had taken place an hour ago. All the attendees had left, and the place was empty save for the long shadows cast by the flagpoles. The flags of the UN and the Solar System Fleet hung from the two tallest poles, and behind them were the flags of the various nations. The flags continued to flap tranquilly in the light breeze. Beyond them was the endless Gobi Desert. A few twittering birds landed in a stand of tamarisk nearby. In the distance, she could see the rolling Qilian Mountains, the snow cover on a few peaks giving them a silvery highlight.

Everything seemed the same, but this world no longer belonged to humans.

Cheng Xin didn’t know what to do. No one had contacted her after the end of deterrence. The Swordholder no longer existed, just like deterrence.

She walked forward aimlessly. When she exited the gates of the compound, two guards saluted her. She was terrified of facing people, but she saw nothing but curiosity in their eyes—they didn’t yet know what had happened. Regulations permitted the Swordholder to come onto the surface for brief intervals, and they must have thought she had come up to investigate the quake. Cheng Xin saw a few military officers standing next to a flying transport parked by the gate. They weren’t even looking at her, merely in the direction she had come from. One of them pointed in that direction.

She turned around and saw the mushroom cloud on the horizon. Formed by the earth and dust thrown up from deep underground, it was very thick, appearing almost solid. It looked so out of place in the serene scene that it resembled a bad Photoshop job. A closer examination led Cheng Xin to imagine it as an ugly bust showing a strange expression in the setting sun. That was where the droplet had penetrated the Earth.

Someone called her name. She turned and saw 艾 AA running toward her. Dressed in a white jacket, her hair waving in the wind, she panted and told Cheng Xin that she had come to see her, but the sentries wouldn’t let her in.

“I’ve brought some flowers for your new place,” she said, pointing at her parked car. Then she turned to the mushroom cloud. “Is that a volcano? Did that cause the earthquake just now?”

Cheng Xin wanted to pull AA into her arms and cry, but she controlled herself. She wanted to delay the moment when this happy girl found out the truth, wanted to let the reverberations of the good times that had just ended linger a bit longer.

Excerpt from A Past Outside of Time Reflections on the Failure of Dark Forest Deterrence

The most important factor in the failure of deterrence was, of course, electing the wrong Swordholder. This is a topic that will be addressed elsewhere in a dedicated chapter. For now, let’s focus on the technical weaknesses in the system design that contributed to the failure.

After the failure, most people immediately pointed to the small number of gravitational wave transmitters as a cause, and blamed people from the early Deterrence Era for dismantling nineteen of the twenty-three completed transmitters. But this reaction represented a failure to grasp the substance of the problem. From data gathered during the droplet attack, a droplet needed slightly more than ten seconds on average to penetrate the crust and destroy a transmitter. Even if the planned one hundred transmitters had been completed and deployed, it wouldn’t have taken long for droplets to destroy the entire system.

The key was that the system could be destroyed. Humankind had had a chance to build an indestructible gravitational wave universal broadcast system, but hadn’t taken it.

The problem wasn’t the number of transmitters, but where they were deployed.

Imagine if the twenty-three transmitters had not been built on or below the surface, but in space—that is, twenty-three spaceships like Gravity. Normally, the ships would be scattered around the Solar System. Even if the droplets had conducted a surprise attack, it would be difficult for them to destroy all of them. One or more of the ships would have time to escape into deep space.

This would have greatly increased the degree of deterrence for the whole system, in a way that would not have been dependent on the Swordholder. The Trisolarans would have known that they controlled insufficient forces within the Solar System to completely destroy the deterrence system, and would have behaved with far more restraint.

Regrettably, there was only one Gravity.