Bunker Era, Year 68 The Two-Dimensional Solar System（2）

While the three were focused on the flattening Sun, Venus and Mars collapsed into the plane as well. Compared to the Sun, however, the two-dimensionalization of these two terrestrial planets was rather unremarkable. The flattened Mars and Venus were very similar to the Earth in terms of their "tree ring" structure. There were many hollow areas near the rim of Mars, places in the Martian crust that contained water, suggesting that Mars had possessed far more water than people thought. After a while, the water also turned an opaque white, but no giant snowflakes appeared. There were giant snowflakes around the flattened Venus, but they weren't anywhere as numerous as the ones near the Earth, and the Venusian snowflakes were yellow in hue, indicating that they were not water crystals. A while later, the asteroids on that side of the Sun were also flattened, completing the other half of the Solar System necklace.

Tiny snowflakes—three-dimensional ones—now fell from the light purple Plutonian sky. These were the nitrogen and ammonia that had sublimated in the burst of energy during the Sun's flattening, and which were now freezing into snow as the temperature plummeted following the Sun's extinguishment. The snow fell more heavily, and soon accumulated a thick layer over the monolith and Halo. Although there were no clouds, the heavy snow blurred Pluto's sky, and the two-dimensional Sun and the planets turned hazy behind a curtain of snow. The world looked smaller.

"Don't you feel at home?" AA lifted both hands and spun in the snow.

"I was just thinking the same thing," Cheng Xin said, and nodded. She had also thought of snow as something unique to the Earth, and the giant snowflakes around the flattened Earth had confirmed this feeling. The snow falling on this cold, dark world on the edge of the Solar System surprisingly provided her a trace of the warmth of home.

Luo Ji watched as AA and Cheng Xin tried to catch the snow. "Hey, you two! Don't even think about taking off your gloves!"

Cheng Xin did feel an impulse to take off her gloves and catch the snow with her bare hands. She wanted to feel the slight chill, and watch the crystalline snowflakes melt with her own body heat.... but of course she had enough presence of mind to not indulge the impulse. The nitrogen-ammonia snowflakes were at a temperature of minus-210-degrees Celsius. If she really took off her gloves, her hand would turn as fragile and hard as glass and the feeling of being on Earth would disappear instantaneously.

"There's no more home," Luo Ji said, shaking his head and leaning against his cane. "Home is now just a picture."

The nitrogen-ammonia snow didn't last long. The snowflakes thinned out and the purple haze from the nitrogen-ammonia atmosphere faded. The sky was once again perfectly transparent and dark. They saw that the Sun and the planets had grown even bigger, indicating that Pluto had moved even closer to that two-dimensional abyss.

When the snow stopped, a bright glowing light appeared near the horizon. The intensity of the light grew rapidly, and soon overwhelmed the fading two-dimensional Sun. Although they couldn't see the details, they knew that it was Jupiter, the Solar System's largest planet, falling into the plane. Pluto spun slowly, and part of the flattened Solar System had fallen below the horizon, so they thought they wouldn't get to witness Jupiter's collapse, but it appeared that the rate of fall into two dimensions was accelerating.

They asked Halo's AI to look for transmissions from Jupiter. Very few images and videos were being transmitted now, and most were indecipherable. Almost all of the messages they got were audio only. Every communication channel was filled with noise, mostly human voices, as though all the remaining space in the Solar System had been filled with a frenzied sea of people. The voices cried, screamed, sobbed, laughed hysterically... and some even sang. The chaotic background noise made it impossible to tell what they were singing, only that it was many voices singing in harmony. The music was solemn, slow, like a hymn. Cheng Xin asked the AI whether it was possible to receive any official broadcasts from the Federation Government. The AI said that all official communications from the government had terminated when the Earth was flattened. The Federation Government couldn't fulfill the promise to carry out its duties until the end of the Solar System after all.

Ships trying to escape continued to stream by the vicinity of Pluto.

"Children, it's time to go," said Luo Ji.

"Let's go together," said Cheng Xin.

"What's the point?" Luo Ji shook his head and smiled. He pointed at the monolith with his cane. "I'm more comfortable over there."

"All right. We'll wait until Uranus is flattened so that we get to spend more time with you," AA said. There really didn't seem to be any point in insisting. Even if Luo Ji got on Halo, it would only delay the inevitable by another hour. He didn't need that bit of time. Indeed, if Cheng Xin and AA didn't have a mission to carry out, they wouldn't care for that bit of time either.

"No. You must go now!" Luo Ji said. He struck the ground with his cane forcefully, which made him float up under the low gravity. "No one knows how much faster the collapse is happening now. Carry out your mission! We can stay in contact, and that's no different from being together."

Cheng Xin hesitated for a moment, then nodded. "All right. We'll leave. Stay in contact!"

"Of course." Luo Ji lifted his cane in farewell and turned to walk toward the monolith. With the light gravity, he almost floated over the snow on the ground and had to use the cane to slow himself. Cheng Xin and AA watched until the aged figure of this Wallfacer, Swordholder, and humanity's final grave keeper disappeared behind the door of the monolith.

Cheng Xin and AA went back inside Halo. The yacht took off right away, its thrusters tossing up snow everywhere. Soon, the ship achieved Pluto's escape velocity—just a hair above one kilometer per second—and reached orbit. From the porthole and the monitor they could see that swaths of white now joined the blue and black patches of the Plutonian surface. The giant words "Earth Civilization," written in multiple scripts and languages, had been covered by the snow and were almost illegible. Halo passed through the gap between Pluto and Charon as though flying through a canyon, the two celestial bodies were so close.

In this "canyon" there were now many other moving stars—the escaping spaceships. They all moved far faster than Halo. One ship swept past Halo at a distance of no more than a hundred kilometers, and the glow from its nozzles lit up Charon's smooth surface. They could clearly see its triangular hull and the nearly ten-kilometer-long blue flame shooting out of its nozzles.

The AI explained, "That's Mycenae, a midsized planetary ship without an ecological cycling system. After leaving the Solar System, a passenger would not last five years, even if all the ship's supplies were used to sustain only them."

The AI didn't know that Mycenae would not be able to leave the Solar System. Like all the other escaping ships, it would continue to exist for no more than three hours in three-dimensional space.

Halo flew out of the Pluto-Charon canyon and left the two dark worlds for open space. They saw the entirety of the two-dimensionalized Sun and Jupiter, whose flattening process was almost over. Now, except for Uranus, the vast majority of the Solar System had fallen into the plane.

"Oh, heavens! Starry sky!" AA cried out.

Cheng Xin knew that she was referring to Van Gogh's painting. True, the universe really did look like the painting. The painting in her memory was almost a perfect copy of the two-dimensional Solar System before her eyes. Giant planets filled space, the areas of the planets seeming to exceed even the gaps between them. But the immensity of the planets did not give them any sense of substantiality. Rather, they looked like whirlpools in space-time. In the universe, every part of space flowed, churned, trembled between madness and horror like fiery flames that emitted only frost. The Sun and the planets and all substance and existence seemed to be only hallucinations produced by the turbulence of space-time.

Cheng Xin now recalled the strange feeling she had experienced each time she had looked at Van Gogh's painting. Everything else in the painting—the trees that seemed to be on fire, and the village and mountains at night—showed perspective and depth, but the starry sky above had no three-dimensionality at all, like a painting hanging in space.

Because the starry night was two-dimensional.

How could Van Gogh have painted such a thing in 1889? Did he, having suffered a second breakdown, truly leap across five centuries and see the sight before them using only his spirit and delirious consciousness? Or, maybe it was the opposite: He had seen the future, and the sight of this Last Judgment had caused his breakdown and eventual suicide.

"Children, is everything all right? What are you going to do next?" Luo Ji appeared in a pop-up window. He had taken off his space suit, and his white hair and beard floated in the low gravity like in water. Behind him was the tunnel that had been intended to last a hundred million years.

"Hello! We're going to toss the artifacts into space," AA said. "But we want to keep Starry Night."

"I think you should hold on to them all. Don't toss any. Take them and leave."

Cheng Xin and AA looked at each other. "Go where?" AA asked.

"Anywhere you like. You can go to any place in the Milky Way. In your lifetimes, you could probably get to the Andromeda Galaxy. Halo is capable of lightspeed flight. It is equipped with the world's only curvature propulsion drive."

Utter shock. AA and Cheng Xin couldn't speak.

"I was a part of the group of scientists who worked on curvature propulsion in secret," said Luo Ji. "After Wade died, those who had worked at Halo City didn't give up. After those who had been imprisoned were released, they built another secret research base, and your Halo Group was revived and developed enough to keep it going. Do you know where the base was? Mercury, another place in the Solar System where few set foot. Four centuries ago, another Wallfacer, Manuel Rey Diaz, used giant hydrogen bombs to blast a crater there. The base was built in that crater, and its construction took over thirty years. The whole base was covered with a dome. They claimed that it was a research institute to study solar activity."

A bright shaft of light pierced the porthole. AA and Cheng Xin ignored it, but the ship's AI explained that Uranus had also undergone "state change," meaning that it had also collapsed into two dimensions. By now, nothing stood between them and Pluto.

"Thirty-five years after Wade's death, the research into curvature propulsion picked up at the Mercury base. They continued from the point where they were able to move a two-millimeter segment of your hair two centimeters. The research continued for half a century—though they were interrupted a few times for various reasons—and they gradually moved from theoretical research to technological development. During the last stages of the development process, they had to perform experiments on large-scale curvature propulsion. This was a problem for the Mercury base because the base's resources were limited, and an experiment would produce massive trails, which would expose the Mercury base's true goals. In reality, based on the comings and goings at the base for more than fifty years, it was inconceivable that the Federation Government had no clue what the Mercury base was really up to, but due to the small scale of the experiments and the fact that all the research was done under cover of other projects, the government had tolerated the base's activities. Large-scale experiments, however, required the government's cooperation. We sought it out, and the collaboration went very well."

"Did they repeal the laws proscribing lightspeed ships?" Cheng Xin asked.

"No, not at all. The government collaborated with us because..." Luo Ji tapped his cane against the ground and hesitated. "Let's not get into that for now. A few years ago, we completed three curvature engines and conducted three unmanned tests. Engine Number One entered lightspeed about one hundred and fifty astronomical units from the Sun, and returned here after flying at lightspeed for a while. For the engine itself, the experiment lasted only ten minutes or so, but for us, it was three years before the engine returned. The second test involved Engines Number Two and Number Three simultaneously. Right now, both of them are outside the Oort Cloud, and should return to the Solar System in six years.

"Engine Number One, which has already been tested, is installed in Halo."

"But how could they have sent Cheng Xin and I alone?" AA shouted. "There should at least be two men with us."

Luo Ji shook his head. "There was no time. The collaboration between the Halo Group and the Federation Government occurred in secret. Very few people knew of the existence of the curvature engines, and even fewer knew where the only engine left in the Solar System was installed. And it was too dangerous. Who knows what people are capable of when the end is nigh? Everyone would fight over Halo, and maybe nothing would be left afterward. And so we had to get Halo away from the Bunker World before releasing news of the dark forest strike to the public. There really wasn't any time left. Cao Bin sent Halo to Pluto because he wanted you to take me with you. He should have just had Halo enter lightspeed at Jupiter."

"Why didn't you come with us?" AA shouted.

"I've lived long enough. Even if I get onto the ship, I won't live much longer. I'd rather stay here as a grave keeper."

"We can come back for you!" Cheng Xin said.

"Don't you dare! There's no time!"

The three-dimensional space they were in accelerated toward the two-dimensional plane. The two-dimensional Sun, which had now completely extinguished and appeared as a vast, dark red, dead sea, took up most of the view from Halo. Cheng Xin and AA noticed that the plane was not completely flat, but undulating! A long wave slowly rolled across the plane. It was a similar wave in three-dimensional space that had allowed Blue Space and Gravity to find warp points to enter four-dimensional space. Even in places where there were no two-dimensional objects in the plane, the rippling wave was apparent. The waves were a visualization of two-dimensional space in three dimensions that occurred only when the two-dimensional space was large enough.

On Halo itself, the space-time distortion produced by the accelerated fall had started to become apparent as space was stretched in the direction of the fall. Cheng Xin noticed that the circular portholes now appeared as ovals, and the slender AA now looked short and squat. But Cheng Xin and AA felt no discomfort, and the ship's systems were operating normally.

"Return to Pluto!" Cheng Xin ordered the AI. Then she turned to Luo Ji's window. "We're going to come back. There's time—Uranus is still being flattened."

The AI replied stiffly, "Among all authorized users in communication range, Luo Ji has the highest authorization level. Only he can order Halo to return to Pluto."

Luo Ji smiled before the tunnel. "If I wanted to go, I would have gotten on the ship with you earlier. I'm too old for voyages far from home. Do not worry about me, children. Like I said, I don't think I've missed anything. Prepare for curvature propulsion!"

Luo Ji's last words were directed at the ship's AI.

"Course parameters?" asked the AI.

"Continue along the current heading. I don't know where you want to go, and I don't think you know, either. If you do think of a destination, just point it out on the star map. The ship is capable of automatic navigation to most stars within fifty thousand light-years."

"Affirmative," said the AI. "Initiating curvature propulsion in thirty seconds."

"Do we need to be immersed in deep-sea fluid?" AA asked—though rationally, she knew that under conventional propulsion, such acceleration would compress her into a pancake no matter what kind of fluid she was immersed in.

"You don't need any kind of preparation. This propulsion method relies on manipulating space, so there's no hypergravity. Curvature propulsion drive online. System is operating within normal parameters. Local space curvature: twenty-three point eight. Forward curvature ratio: three point forty-one to one. Halo will enter lightspeed in sixty-four minutes, eighteen seconds."

For Cheng Xin and AA, the AI's announcement was like a Full Stop order, because everything suddenly quieted down. They understood that the silence was due to the nuclear fusion engine being shut off, but the humming produced by the fusion reactor and the thrusters disappeared without being replaced by any other noise. It was hard to believe that some other engine had been started.

But signs of curvature propulsion did appear. The distortion in space gradually disappeared: The portholes returned to being circles, and AA looked slender again. Looking through the portholes, they could still see other escaping ships passing by Halo, but they now passed far more slowly.

The ship's AI began to play some of the messages passing between the escaping ships—perhaps because the messages concerned Halo.

"Look at that ship! How is it able to accelerate so fast?" a woman screamed.

"Oh! The people inside must have been crushed into meat pies," a man said.

Another man spoke up. "You idiots. The ship itself would be crushed under that kind of acceleration. But look at it: It's perfectly fine. That's not a fusion drive, but something entirely different."

"Curvature propulsion? A lightspeed ship? That's a lightspeed ship!"

"The rumors were true, then. They were building secret lightspeed ships so that they could escape...."

"Aaahhhhh..."

"Hey, any ships ahead? Stop that ship! Crash into it. No one should live if we all have to die!"

"They can reach escape velocity! They can run away and live! Ahhhh! I want the lightspeed ship! Stop them; stop them and kill everyone inside!"

Another scream—this one from AA inside the ship. "How can there be two Plutos?"

Cheng Xin turned to the information window AA was looking at. The window showed a view of Pluto taken by the ship's monitoring system. Although Pluto was some distance away, it was clear that both Pluto and Charon had been duplicated, and the twins were lined up side by side. Cheng Xin noticed that some of the flattened objects in the two-dimensional space had also been duplicated. The effect was like selecting a portion of a picture using image-processing software, cloning it, and then moving the clone a bit to the side.

"That's due to the fact that light slows down inside the trail left by Halo," Luo Ji said. His image was growing distorted, but his voice still came through clearly. "Pluto is still moving. One of the Plutos you are seeing is the result of slow light. Once Pluto has moved outside of Halo's trail, light traveling at standard speed provides you with a second image. That's why you're seeing double."

"The light slows down?" Cheng Xin sensed a great secret was being revealed.

Luo Ji continued, "I understand that you figured out curvature propulsion from a small boat propelled by soap. Let me ask you: After the ship reached the other side of the bathtub, did you pull it back and try again?"

They hadn't. Due to the fear of sophons, Cheng Xin had tossed the paper boat aside. But it was easy to figure out what would have happened.

"The ship would not move, or at least it would only move slowly," Cheng Xin said. "After the first trip, the surface tension of the water in the tub had already been reduced."

"That's right. It's the same principle with lightspeed ships. The very structure of space itself is changed by the trail of a curvature-propelled ship. If a second curvature-propelled ship were placed inside the trail of the first, it would hardly move. Within the trails of lightspeed ships, one must use a more powerful curvature propulsion drive. It would still be possible to use curvature propulsion to achieve the highest speed possible within such a space, but the maximum velocity is much lower than the maximum velocity of the first ship. In other words, the speed of light through vacuum is lowered within the trail of lightspeed ships."

"How much lower?"

"Theoretically, it could be reduced to zero, but that's not achievable in reality. But if you adjust the curvature ratio of Halo's engine to the maximum, you can lower the speed of light in its trail down to exactly what we've been looking for: sixteen point seven kilometers per second."

"Then you'd have..." AA said, staring at Luo Ji.

The black domain, Cheng Xin thought.

"The black domain," Luo Ji said. "Of course, a single ship is insufficient to produce a black domain containing an entire star and its planetary system. We calculated that it would take more than a thousand curvature propulsion ships to accomplish such a thing. If all these ships started near the Sun and spread out in every direction at lightspeed, the trails they produced would expand and connect to each other, forming a sphere that contained the entire Solar System. The speed of light within this sphere would be sixteen point seven kilometers per second—a reduced-lightspeed black hole, or a black domain."

"So the black domain can be a product of lightspeed ships...."

In the cosmos, the trail of a curvature propulsion drive could be a sign of danger, as well as a safety announcement. A trail far away from a world was the former; a trail that shrouded a world the latter. It was like a noose, indicating danger and aggression when held in the hand, but safety when wrapped around the holder's own neck.

"Correct, but we found out about it too late. While studying curvature propulsion, the experimenters plowed ahead of the theoreticians. You should know that was Wade's style. Many experimental discoveries could not be explained by theory, but without a theoretical framework, some phenomena were simply ignored. During the earliest years of research—when their biggest achievement was moving your hair—the trails produced by curvature propulsion were thin and small, and hardly anyone paid any attention, even though there were plenty of signs of something strange going on: For instance, after the trail expanded, the low speed of light caused quantum integrated circuits in nearby computers to malfunction, but no one sought to investigate. Later, after the experiments grew in scale, people finally discovered the secret of lightspeed trails. It was because of this discovery that the Federation Government agreed to collaborate with us. They did, in fact, pour all the resources they could command into the development of lightspeed spaceships, but there just wasn't enough time." Luo Ji shook his head and sighed.

Cheng Xin said what he couldn't bring himself to say. "There were thirty-five years between the Halo City Incident and the completion of the Mercury base. Thirty-five precious years were lost."

Luo Ji nodded. Cheng Xin thought the way he looked at her was no longer kind, but rather resembled the fires of the Last Judgment. His gaze seemed to say, Child, look at what you've done.

Cheng Xin now understood that of the three paths of survival presented to humanity—the Bunker Project, the Black Domain Plan, and lightspeed ships—only lightspeed ships were the right choice.

Yun Tianming had pointed this out, but she had blocked it.

If she hadn't stopped Wade, Halo City might have achieved independence. Even if the independence was short-lived, they could have discovered the effects of lightspeed trails and changed the government's attitude toward lightspeed ships. Humanity might have had time to construct a thousand lightspeed ships and build the black domain, to avoid this dimensional strike.

Humanity could have divided into two parts: those who wanted to fly to the stars, and those who wanted to stay within the black domain and live in tranquility. Each would have gotten what they wanted.

In the end, she had committed another grave error.

Twice, she had been placed in a position of authority second only to God, and both times she had pushed the world into the abyss in the name of love. This time, no one could fix her mistake for her.

She began to hate someone: Wade. She hated that he had kept his promise. Why? Out of his masculine pride, or for her? Cheng Xin understood that Wade did not know the effects of curvature propulsion trails. His goal in researching lightspeed ships was stated eloquently by that anonymous Halo City soldier: a fight for freedom, for a chance to live as free men in the cosmos, for the billions and billions of new worlds out there. She believed that if he had known that lightspeed spaceflight was the only path to life for humanity, he would not have kept his promise.

She could not shirk her responsibility. It didn't matter whether she really was second only to God—if she was in that position, she had to carry out her duty.

Not long ago on Pluto, Cheng Xin had experienced one of the most relaxed moments of her life. Indeed, it was easy to face the end of the world: All responsibilities were gone, as were all worries and anxieties. Life was as simple and pure as the moment when one first emerged from the mother's womb. Cheng Xin just had to wait in peace for her poetic, artistic end, for her moment to join the giant painting of the Solar System.

But now, everything had been turned upside down. Early cosmology had presented a paradox: If the universe was infinite, then every spot in the universe would feel the cumulative effects of the infinite gravity exerted by an infinity of celestial bodies. Cheng Xin really did feel an infinite gravity now. The power came from every corner of the universe, ruthlessly tearing at her soul. The horror of her last moments as the Swordholder 127 years ago resurfaced as four billion years of history pressed down on her and suffocated her. The sky was full of eyes staring at her: the eyes of dinosaurs, trilobites, ants, birds, butterflies, bacteria... just the number of men and women who had lived on the Earth possessed a hundred billion pairs of eyes.

Cheng Xin saw AA's eyes, and understood the words in her gaze: You've finally experienced something worse than death.

Cheng Xin knew that she had no choice but to live on. She and AA were the last two survivors of human civilization. Her death would mean the death of half of all that was left of humanity. Living on was the appropriate punishment for her mistake.

But the course ahead was a blank. In her heart, space was no longer black, but colorless. What was the point of going anywhere?

"Where should we go?" Cheng Xin muttered.

"Go find them," Luo Ji said. His image was even more blurred and now only black and white.

His words illuminated Cheng Xin's dark thoughts like lightning. She and AA looked at each other and immediately understood who "them" meant.

Luo Ji continued, "They're still alive. The Bunker World received a gravitational wave transmission from them five years ago. It was a short message, and didn't explain where they were. Halo will periodically hail them with gravitational waves. Maybe you'll find them; maybe they'll find you."

Luo Ji's black-and-white image disappeared as well, but they could still hear his voice. He said one last thing, "Ah, it's time for me to go into the picture. Safe travels, children."

The transmission from Pluto was cut off.

On the monitor, they could see Pluto light up and expand in two dimensions. The part of Pluto containing the museum was the first to touch the plane.

The Doppler effect of Halo's speed was now visible. The light from the stars ahead shifted to bluish, while the light from the stars behind shifted to reddish. The color shift was apparent in the two-dimensional Solar System.

Outside, no other fleeing spaceships could be seen; Halo had passed them all. All the fleeing spaceships were now falling onto the two-dimensional space like drops of rain against glass.

Very few transmissions could now be received from the direction of the Solar System. Due to the Doppler effect, the brief bursts of voices sounded strange, like singing.

"We're very close! Are you behind us?"..."Don't do this! No!"..."There's no pain. I'm telling you, it'll be over in a flash."..."You still don't believe me, after all this? Fine, don't believe me."..."Yes, sweetie, we'll become very thin."..."Come here! We should be together."

Cheng Xin and AA listened. The voices became fewer and fewer, and separated by longer gaps. After thirty minutes, they heard the last voice coming out of the Solar System:

"Ahhhhhhhhh—"

The voice was cut off. The giant painting called the Solar System was complete.

Halo continued to fall toward the plane. The speed it had already achieved was slowing down its fall, but the ship still hadn't achieved escape velocity. By now, Halo was the only man-made three-dimensional object in the Solar System, and Cheng Xin and AA were the only people not in the painting. Halo was very close to the plane, and from this angle, looking at the two-dimensional Sun was like looking at the sea from shore: the dim, dark red surface stretched into the distance without bounds. The freshly flattened Pluto was now very large, and still expanded at a rate that was visible to the naked eye. Cheng Xin examined the exquisite "tree rings" of Pluto and tried to find traces of the museum, but she couldn't see anything—it was too small. The giant waterfall that was three-dimensional space tumbling into the flat plane seemed inexorable. Cheng Xin began to doubt whether the curvature propulsion engine really was capable of propelling the ship to lightspeed. She hoped for everything to be over.

But then, the ship's AI spoke.

"Halo will enter lightspeed in one hundred and eighty seconds. Please select a destination."

"We don't know where to go," said AA.

"You can select a destination after we've entered lightspeed. However, you won't subjectively be spending much time in lightspeed, and it's easy to overshoot your destination. It's best if you select it now."

"We don't know where to find them," Cheng Xin said. Their existence gave the future some light, but she still felt lost.

AA clutched Cheng Xin's hands. "Have you forgotten? Other than them, he also exists in the universe."

Yes, he still exists. Cheng Xin was overwhelmed by heartache. She had never yearned to see anyone as much as him.

"You have a date," AA said.

"Yes, we have a date," Cheng Xin repeated mechanically. The torrents of emotion left her numb.

"Then let's go to your star."

"Yes, let's go to our star!" Cheng Xin turned to the ship's AI. "Can you find DX3906? That was the assigned number back at the beginning of the Crisis Era."

"Yes. The star is now numbered S74390E2. Please confirm."

A large holographic star map appeared before them. It showed everything within five hundred light-years of the Solar System. One of the stars glowed bright red, and a white arrow pointed at it. Cheng Xin was very familiar with it.

"That's the one. Let's go there."

"Course set and confirmed. Halo will enter lightspeed in fifty seconds."

The holographic star map disappeared. In fact, the ship's entire hull disappeared, and Cheng Xin and AA seemed to be floating in space itself. The AI had never employed this display mode before. In front of them was the starry sea that was the Milky Way, which was now pure blue, reminding them of the real sea. Behind them was the two-dimensional Solar System, suffused with a bloody red.

The universe shuddered and transformed. All the stars in front of them shot straight ahead, as though that half of the universe had transformed into a black bowl and all the stars were falling into the bottom. They clustered ahead of the ship and fused into a single glow, like a giant sapphire in which it was not possible to distinguish individual stars. From time to time, individual stars shot out of the sapphire and swept past the pure black space to fall behind the ship, changing color the whole way: from blue to green, then yellow, and turning red once they were behind the ship. Looking back from the ship, the two-dimensional Solar System and the stars fused into a red ball like a campfire at the end of the universe.

Halo flew at the speed of light toward the star that Yun Tianming had given Cheng Xin.