Death's End

by Cixin Liu

  “Niagara Falls! Heh heh heh heh…”

  Bai Aisi looked back and saw a sight that made his blood curdle: The pit now took up his entire field of vision. The whole desert was swallowed up by it, and the world was like a giant pit whose bottom was an abyss. At the rim, flowing sand poured in and formed a spectacular yellow sandfall. Ding Yi wasn’t exactly right in his description: The Niagara Falls were minuscule compared to this sandfall of terror. The sandfall extended from the near edge of the pit all the way to the far edge on the horizon, forming an immense sandfall ring. The sand torrents rumbled as if the world itself were coming apart. The car continued to slide toward the pit, faster and faster. Bai Aisi floored the accelerator and leaned his weight into it, but there was no effect.

  “You fool. Do you really think we can escape?” Ding Yi said while still laughing sinisterly. “Escape velocity! Why don’t you calculate the escape velocity? Are you thinking with your butt? Heh heh heh heh…”

  The car tumbled over the rim and dropped in the sandfall. The sand raining down around them seemed to stop as everything plunged into the abyss. Bai Aisi screamed with utter terror, but he couldn’t hear himself. All he heard was Ding Yi’s wild laughter.

  “Hahahahaha … There’s no table untouched at the dinner party, and there’s no virgin untouched in the universe … waheeheeheehee … wahahahaha…”

  * * *

  白 Ice woke from his nightmare and found himself covered in cold sweat. Around him, more droplets of sweat hung suspended in air. He floated for a while, his body stiff, and then dashed out of his cabin and headed for Vasilenko’s cabin. It took a while before the door opened, as Vasilenko was also sleeping.

  “General! Do not keep that thing, that thing they call a slip of paper, in the spaceship! No, I mean, don’t allow Revelation to hover around it. We should leave immediately, and get as far away as possible!”

  “What have you discovered?”

  “Nothing. It’s my intuition.”

  “You don’t look so good. Exhaustion? I think you’re worrying too much. That thing … I don’t think it’s anything. There’s nothing inside. It should be harmless.”

  白 Ice grabbed Vasilenko by the shoulders and gazed into his eyes. “Don’t be arrogant!”

  “What?”

  “Don’t be arrogant. Weakness and ignorance are not barriers to survival, but arrogance is. Remember the droplet!”

  白 Ice’s last sentence had an effect. Vasilenko stared at him in silence for a few seconds, then nodded slowly. “All right, Dr. Bai, I’ll listen to you. Revelation will depart from the slip and back off one thousand kilometers. We’ll leave just a pinnace to monitor it.… Maybe two thousand kilometers?”

  白 Ice let Vasilenko go and wiped his forehead. “You decide. I suggest, the farther the better. I will write a formal report as soon as possible and let Command know of my theories.” Stumbling, he drifted away.

  * * *

  Revelation left the slip. It passed through the ship’s hull and was reexposed to space. Since the background was dark again, it once again appeared to be an opaque white slip of paper. Revelation pulled away from the slip until the two were about two thousand kilometers apart, then continued to sail in parallel, waiting for the arrival of Tomorrow. A pinnace with a crew of two stayed about ten meters from the slip to monitor it continuously.

  The gravitational waves emitted by the paper slip continued to diminish, and its light gradually dimmed.

  On Revelation, 白 Ice shut himself in the laboratory. Around him, he set up more than a dozen information windows, all connected to the ship’s quantum computer, which was carrying out massive computations. The windows were packed with equations, curves, and matrices. Surrounded by the windows, 白 Ice was anxious and irritable, like a trapped animal.

  Fifty hours after the separation from Revelation, the gravitational wave emitted from the paper slip disappeared completely. The white light from it blinked twice and also went out. The slip of paper was gone.

  “Has it evaporated?” Vasilenko asked.

  “I don’t think so. But we can’t see it anymore.” 白 Ice shook his head wearily and closed the information windows around him one by one.

  After another hour during which no signs of the slip could be detected, Vasilenko ordered the pinnace to return to Revelation. But the two crew members on duty in the pinnace didn’t acknowledge the order; the radio only transmitted a hurried conversation between them.

  “Look out below! What’s going on?”

  “It’s rising!”

  “Don’t touch it! Get out!!”

  “My leg! Ahhh—”

  After the scream, the monitoring terminal on Revelation showed one of the crew members leaving the pinnace and activating the thrusters on his space suit in an attempt to escape. They saw a bright light; the source was the bottom of the pinnace, which was melting! The pinnace looked like a scoop of ice cream dropped onto a scalding sheet of glass: The bottom was melting and spreading in every direction. The “glass” was invisible, and the plane’s existence was indicated only by the spreading pool of melted pinnace material. The pool spread into an extremely thin sheet and emitted bewitching, colorful lights, like fireworks scattered through a sheet of glass.

  The escaped crewman flew some distance but seemed to be pulled by gravity toward that plane marked by the melted pinnace. His feet touched the plane and immediately melted into a shiny puddle. The rest of his body also began to spread out on the plane, and he had time only for a scream that was abruptly cut off.

  “All hands to hypergravitation seats! Full Ahead!”

  As soon as he saw the escaping crewman’s feet touch the invisible plane, Vasilenko gave the order. Revelation wasn’t a stellar ship, so when it engaged in Full Ahead acceleration, the crew did not need to enter into the protective deep-sea state. But the hypergravity was enough to sink everyone deep into their seats. Since the order was given in such a hurry, a few couldn’t get to their seats in time and fell to the stern of the ship with injuries. Revelation’s exhaust nozzles emitted a plasma stream several kilometers long that pierced the dark night of space. Far in the distance, where the pinnace was still melting, they could see the phosphorescent glow like will-o’-the-wisps in the wilderness.

  From the zoomed-in view on the monitoring terminal, they could see that only the very top part of the pinnace was left, and that too soon disappeared into the brilliant plane. The body of the dead crewman was also diffused into the plane, showing up as a gigantic, man-shaped glow. His body had been transformed into a slice on the plane without thickness. Though large in area, it had no volume.

  “We’re not moving,” the pilot of Revelation said. He had trouble talking through the hypergravity. “The ship isn’t accelerating.”

  “What are you babbling about?” Vasilenko wanted to shout, but the hypergravity turned it into a whisper.

  It really did seem as if the pilot should have been wrong. Everyone on the ship was pressed against their seat by hypergravity, which indicated that the ship was in the process of extreme acceleration. It was visually impossible for a passenger to tell whether the ship was moving in space because all celestial bodies that could act as reference points were too far away, so they couldn’t see parallax in a short time frame. However, the ship’s navigation system could detect even tiny amounts of motion and acceleration; it couldn’t be wrong.

  Revelation was under hypergravity, but had no acceleration. Some force had nailed it to this point in space.

  “There is acceleration,” said 白 Ice weakly. “But the space in this region is flowing in the opposite direction, thus canceling out our motion.”

  “The space is flowing? Where to?”

  “There, of course.”

  白 Ice couldn’t lift his hand, which was now too heavy. But everyone knew where he meant. Revelation sank into a deathlike silence. Normally, hypergravity made people feel safe, as though they were escaping from danger under the embrace of some protective pow
er. But now it seemed as oppressive and suffocating as a tomb.

  “Open a channel to Command,” 白 Ice said. “There’s no time, so we’ll treat this as our formal report.”

  “Channel open.”

  “General, you once said, ‘I don’t think it’s anything. There’s nothing inside.’ You were right. That slip really wasn’t anything, and contained nothing. It’s only space, just like the space around us, which isn’t anything and contains nothing. But there’s a difference: It’s two-dimensional. It’s not a block, but a slice. A slice without thickness.”

  “Hadn’t it evaporated?”

  “The protective field around it evaporated. The force field acted like packaging that separated the two-dimensional space from the three-dimensional space. But now the two are in direct contact. Do you remember what Blue Space and Gravity saw?”

  No one answered, but they all remembered: the four-dimensional space falling into three dimensions, like a waterfall off a cliff.

  “Just as four-dimensional space collapses into three dimensions, three-dimensional space can collapse into two dimensions, with one dimension folding and curling into the quantum realm. The area of that slice of two-dimensional space—it only has area—will rapidly expand, causing more space to collapse.… We’re now in space that is falling toward two dimensions, and ultimately, the entire Solar System will follow. In other words, the Solar System will turn into a painting with no thickness.”

  “Can we escape it?”

  “Escaping this is like rowing a boat above a waterfall. Unless we exceed a certain escape velocity, we’ll tumble over the cliff. It’s like tossing a pebble up from the ground: No matter how high you throw the rock, it will eventually fall back down. The entire Solar System is within the zone of collapse, and anyone trying to escape must reach escape velocity.”

  “What is the escape velocity?”

  “I’ve computed it four separate times. Pretty sure I got it right.”

  “What is it?!”

  Everyone aboard Revelation and Alaska held their breaths and listened to this final calculation as representatives of humanity.

  白 Ice calmly announced his judgment. “Lightspeed.”

  The navigation system showed that Revelation was now moving in the opposite direction from its heading. It started by moving slowly toward the two-dimensional space, but gradually accelerated. The ship’s drive was still powering Full Ahead. This would at least slow down the rate of the ship’s fall and delay the inevitable.

  On the plane two thousand kilometers away, the light emitted by the two-dimensionalized pinnace and crewmen had already gone out. Compared to collapsing from four dimensions to three, the fall from three dimensions to two gave off much less energy. Two two-dimensional structures were revealed clearly by the starlight. On the two-dimensionalized pinnace, it was possible to see the details of three-dimensional structures unfolded in two dimensions—the crew cabin, the fusion reactor, and so on—as well as the curled-up figure of the crewman in the cabin. In the figure of the other crewman, the bones and blood vessels could be clearly discerned, as well as all the body parts. During the process of falling into two dimensions, every point on a three-dimensional object was projected onto the plane in accordance with precise geometric principles, and so these two figures turned out to be the most complete and precise images of the original three-dimensional pinnace and people. All the internal structures were now laid out side by side in two dimensions with nothing hidden. The projection process, however, was very different from that used in engineering drawings, and so it was difficult to visually reimagine the shapes’ original three-dimensional structure. The greatest difference from engineering drawings lay in the fact that the two-dimensional unfolding occurred at every scale: All the original three-dimensional structures and details were laid out in parallel in two dimensions, and the result replicated, in some measure, the effect of viewing the three-dimensional world from four-dimensional space. This closely resembled drawings of fractals: No matter how much you zoomed in on a part of the image, it would get no less complex. However, fractals were theoretical concepts—actual representations were inevitably limited by the resolution, and after zooming in a number of times, the images lost their fractal nature. The complexity of the two-dimensionalized three-dimensional objects, on the other hand, was real: The resolution was at the level of fundamental particles. On the monitoring terminal of Revelation, the eye could only see a limited resolution, but the complexity and number of details already made the viewers dizzy. This was the universe’s most complicated image; staring at it for too long would drive one mad.

  Of course, the pinnace and the crewmen no longer possessed any thickness.

  It was unclear how large the plane had spread by now; only those two images indicated its presence.

  Revelation slid faster toward the plane, toward that abyss whose thickness was zero.

  “Everyone, don’t be sad. No one will be able to escape from the Solar System, not even a bacteria or virus. All of us will become a part of this grand picture.” 白 Ice now looked calm and stoic.

  “Stop accelerating,” said Vasilenko. “What difference does a few minutes make? Let’s at least breathe easier at the end.”

  Revelation’s engine shut off. The plasma column at the stern of the ship disappeared, and the ship drifted, powerless, in space. In reality, the ship was still accelerating toward the two-dimensional patch of space, but since the ship moved along with the surrounding space, those inside could not feel any gravity from acceleration. They enjoyed the weightlessness and took deep breaths.

  “You know what I’m thinking of? Needle-Eye’s pictures from Yun Tianming’s fairy tales,” 白 Ice said.

  Only a few people aboard Revelation knew about Yun Tianming’s secret message. Now, in a flash, they all understood the meaning of this detail in the stories. It was a simple metaphor, and there were no bearing coordinates because it was so direct. Yun must have thought he was taking a great risk to put such an obvious metaphor into his stories, yet he had to try because the message was so important.

  He probably thought that with the knowledge of Blue Space and Gravity’s discoveries, humanity would understand the metaphor. Unfortunately, he had overestimated their ability to comprehend.

  The inability to decipher this key piece of information led humanity to place all their hopes in the Bunker Project.

  It was true that both dark forest strikes humans had witnessed involved photoids, but they ignored a salient fact: Those two target planetary systems were structured differently from the Solar System. The star known as 187J3X1 had three giant Jupiter-like planets, but they all orbited extremely close to their sun. Their average distance from the sun was but 3 percent of the distance from Jupiter to the Sun, even closer than Mercury’s orbit. Since they almost brushed up against their sun, the solar explosion destroyed them completely, and they could not have been used as barriers. The Trisolaran system, on the other hand, had only one planet, Trisolaris.

  The structure of the planetary system around a star was a characteristic observable from a distance. For a sufficiently advanced civilization, a quick glance was sufficient.

  If humans could figure out the plan to use the gas giants as barriers, couldn’t observers from such advanced civilizations do so, as well?

  Weakness and ignorance are not barriers to survival, but arrogance is.

  Revelation was now no more than a thousand kilometers from the plane; it fell faster and faster.

  “Thank you, everyone, for doing your duty. Although we haven’t been together long, we worked together well,” Vasilenko said.

  “I also thank every member of the human race,” said 白 Ice. “Once, we lived together in the Solar System.”

  Revelation fell into the two-dimensional space. In a few seconds, it was flattened. Light akin to fireworks once again lit up the darkness of space. This was a vast two-dimensional image that could be clearly seen from Alaska, a hundred thousand kilometers
away. It was possible to distinguish every individual on Revelation: They were laid out side by side, holding hands, every single cell in their body exposed to space in two dimensions.

  They were the first to be painted into this grand painting of annihilation.

  Bunker Era, Year 68

  Pluto

  “Let’s head back to the Earth,” Cheng Xin said softly. This was the first idea that floated up through the chaos and darkness of her jumbled thoughts.

  “The Earth is not a bad place to wait for the end. A falling leaf seeks to return to the root. But we hope Halo will go to Pluto,” Cao Bin said.

  “Pluto?”

  “Pluto is at its apogee, rather far from the two-dimensional space. The Federation Government is about to issue a formal attack alert to the world, and many ships will be headed there. Although the final result will be the same, at least there will be more time left.”

  “How much longer?”

  “The entire Solar System within the Kuiper Belt will collapse into two dimensions in eight to ten days.”

  “That’s not long enough to be worth worrying about. Let’s go back to Earth,” said AA.

  “The Federation Government would like to ask you to do something.”

  “What can we possibly do now?”

  “Not anything important. There’s nothing important now. But someone came up with the idea that theoretically, there might exist image-processing software that could process a two-dimensionalized image of a three-dimensional object and re-create the three-dimensional object. We hope that in the distant future, some intelligent civilization might re-create a three-dimensional representation of our world from its two-dimensionalized image. Though it would be nothing more than a dead representation, at least human civilization would not be forgotten.

  “The Earth Civilization Museum is on Pluto. A large portion of humanity’s precious artifacts are stored there. The museum is buried under the surface, however, and we are concerned that during the process of falling into the plane, these artifacts would be mixed together with the strata of the crust and their structures would be damaged. We’d like to ask you to carry some of the artifacts away from Pluto on Halo and scatter them in space so that they can fall into two dimensions separately. This way, their structures would be preserved without harm in two dimensions. I guess this counts as a kind of rescue mission.… Of course, I admit that the idea is nearly science fiction, but doing something now is better than doing nothing.