by Cixin Liu
“Pay attention to the name. It’s a monument,” the division head corrected solemnly. Laughing, he said to Yan Dong, “However, the idea he put forth is very good: He proposed that everyone in the world donate a tooth. Those teeth can be used to create a gigantic tablet. Carving a word on each tooth is sufficient to engrave the most detailed history of human civilization on the tablet.” He pointed at a model that looked like a white pyramid.
“This is blasphemy against humanity,” a bald-headed artist shouted. “The worth of humanity lies in its brains, but he wants to commemorate us with our teeth!”
The long-haired artist took another swig from his bottle. “Teeth.… Teeth are easy to preserve.”
“The vast majority of people are still alive!” Yan Dong repeated solemnly.
“But for how long?” the long-haired artist said. As he asked this question, his enunciation suddenly became precise. “Water no longer falls from the sky. The rivers have dried. Our crops have utterly failed for three years now. Ninety percent of the factories have stopped production. The remaining food and water, how long can that sustain us?”
“You heap of waste.” The bald-headed artist pointed at the bureau chief. “Bustling around for five years and you still can’t bring even one block of ice back from space.”
The bureau chief laughed off the bald-headed artist’s criticism. “It’s not that simple. Given current technology, forcing down one block of ice from orbit isn’t hard. Forcing down one hundred, up to one thousand blocks of ice is doable. But forcing back all two hundred thousand blocks of ice orbiting the Earth, that’s another matter completely. If we use conventional techniques, a rocket engine could slow a block of ice enough that it would fall back into the atmosphere. That would mean building a large number of reusable high-power engines, then sending them into space. That’s a massive-scale engineering project. Given our current technology level and what resources we’ve stockpiled, there are many insurmountable obstacles. For example, in order to save the Earth’s ecosystem, if we start now, we’d need to force down half the blocks of ice within four years, an average of twenty-five thousand per year. The weight of rocket fuel required would be greater than the amount of gasoline humanity used in one year during the Oceaned Days! Except it isn’t gasoline. It’s liquid hydrogen, liquid oxygen, dinitrogen tetroxide, unsymmetrical dimethylhydrazine, and so on. They need over a hundred times more energy and natural resources to produce than gasoline. Just this one thing makes the entire plan impossible.”
The long-haired artist nodded. “In other words, doomsday is not far away.”
The bureau chief said, “No, not necessarily. We can still adopt some nonconventional techniques. There is still hope. While we’re working on this, though, we must still plan for the worst.”
“This is exactly why I came,” Yan Dong said.
“To plan for the worst?” the long-haired artist asked.
“No, because there’s still hope.” She turned to the bureau chief. “It doesn’t matter why you brought me here. I came for my own purpose.” She pointed to her bulky travel bag. “Please take me to the Ocean Recovery Division.”
“What can you do in the Ocean Recovery Division? They’re all scientists and engineers there,” the bald-headed artist wondered.
“I’m a research fellow in applied optics.” Yan Dong’s gaze swept past the artists. “Besides daydreaming along with you, I can also do some practical things.”
* * *
After Yan Dong insisted, the bureau chief brought her to the Ocean Recovery Division. The mood here was completely different from the Monument Division. Everyone was tense, working on their computers. A drinking fountain stood in the middle of the office. They could take a drink whenever they wanted. This was treatment worthy of kings. But considering that the hope of the world rested on the people in this room, it wasn’t so surprising.
When Yan Dong saw the Ocean Recovery Division’s lead engineer, she told her, “I’ve brought a plan for reclaiming the ice blocks.”
As she spoke, she opened her travel bag. She took out a white tube about as thick as an arm, followed by a cylinder about a meter long. Yan Dong walked to a window that faced the sun. She stuck the cylinder out the window, then shook it back and forth. The cylinder opened like an umbrella. Its concave side was plated with a mirror coating. That turned it into something like a parabolic reflector for a solar stove. Next, Yan Dong pushed the tube through a small hole at the bottom of the paraboloid, then adjusted the reflector so that it focused sunlight at the end of the tube. Immediately, the other end of the tube cast an eye-stabbing point of light on the floor. Because the tube lay flat on the floor, the point was an exaggerated oval.
Yan Dong said, “This uses the latest optical fiber to create a waveguide. There’s very little attenuation. Naturally, an actual system would be much larger than this. In space, a parabolic reflector only about twenty meters in diameter can create a point of light at the other end of the waveguide with a temperature of over three thousand degrees.”
Yan Dong looked around. Her demonstration hadn’t produced the reaction she’d expected. The engineers took a look, then returned to their computer screens, paying her no mind. It wasn’t until a stream of dark smoke rose from the point of light on the antistatic floor that the nearest person came over and said, “What did you do? I doubt it’s hot.”
At the same time, the person nudged back the waveguide, moving the light coming through the window away from the focal length of the parabolic reflector. Although the point was still on the floor, it immediately darkened and lost heat. Yan Dong was surprised at how adept the person was at adjusting the thing.
The lead engineer pointed at the waveguide. “Pack up your gear and drink some water. I heard you took the train. The one to here from Changchun is still running? You must be extremely thirsty.”
Yan Dong desperately wanted to explain her invention, but she truly was thirsty. Her throat burned and it was painful to speak.
“Very good. This is a really practical plan.” The lead engineer handed Yan Dong a glass of water.
Yan Dong drained the glass of water in one gulp. She looked blankly at the lead engineer. “Are you saying that someone has already thought of this?”
The lead engineer laughed. “Spending time with aliens has made you underestimate human intellect. In fact, from the moment the low-temperature artist sent the first block of ice into space, many people have come up with this plan. Afterward, there were lots of variants. For example, some used solar panels instead of reflectors. Some used wires and electric heating elements instead of waveguides. The advantage is that the equipment is easy to manufacture and transport. The disadvantage is the efficiency is not as high as waveguides. We’ve been researching this for five years now. The technology is already mature. The equipment we need has mostly been manufactured.”
“Then why haven’t you carried the plan out?”
An engineer next to them said, “With this plan, the Earth will lose twenty-one percent of its water. Either during propulsion as vaporized steam or during reentry from high-temperature dissociation.”
The lead engineer turned to that engineer. “We don’t know that yet. The latest American simulations show, below the ionosphere, the hydrogen produced by high-temperature dissociation during reentry will immediately recombine with the surrounding oxygen into water. We overestimated the high-temperature-dissociation loss. The total loss estimate is around eighteen percent.” She turned back to Yan Dong. “But this percentage is high enough.”
“Then do you have a plan to bring back all of the water from space?”
The lead engineer shook her head. “The only possibility is to use a nuclear fusion engine. But, right now, on Earth, controlled nuclear fusion isn’t within our capabilities.”
“Then why aren’t you acting more quickly? You know, if you dither around, the Earth will lose one hundred percent of its water.”
The lead engineer nodded. “So, after a long t
ime of hesitation, we’ve decided to act. Soon, the Earth will be in for the fight of its life.”
Reclaiming the Oceans
Yan Dong joined the Ocean Recovery Division, in charge of receiving and checking the waveguides that had been produced. Although this wasn’t a core posting, she found it fulfilling.
One month after Yan Dong arrived at the capital, humanity’s project to reclaim the oceans started.
Within one short week, eight hundred large-scale carrier rockets shot into the sky from every launch site in the world, sending fifty thousand tons of freight into Earth orbit. Then, from the North American launch site, twenty space shuttles ferried three hundred astronauts into space. Because launches generally followed the same route, the skies above the launch sites all had a single rocket contrail that never dispersed. Viewed from orbit, it seemed like threads of spider silk stretching up from every continent into space.
These launches increased human space activity by an order of magnitude, but the technology used was still twentieth-century technology. People realized, under existing conditions, if the entire world worked together and risked everything on one attempt, it could do anything.
On live television, Yan Dong and everyone else witnessed the first time a deceleration propulsion system was installed on a block of ice.
To make things less difficult, the first blocks of ice they forced back weren’t the ones that rotated about their own axes. Three astronauts landed on a block of ice. They brought with them the following equipment: an artillery-shell-shaped vehicle that could drill a hole into the block of ice, three waveguides, one expeller tube, and three folded-up parabolic reflectors. It was only now that anyone could get the sense of the immense size of a block of ice. The three people seemed to land on a tiny crystalline world. Under intense sunlight in space, the giant field of ice under their feet seemed unfathomable.
Near and far, innumerable similar crystalline worlds hung in the black sky. Some of them still rotated about their own axes. The surrounding rotating and nonrotating blocks of ice reflected and refracted the sunlight. On the ice the three astronauts stood on, they cast a dazzling pattern of ever-changing light and shadow. In the distance, the blocks of ice in the ring looked smaller and smaller, but gathered closer and closer together, gradually shrinking into a delicate, silver belt twisting toward the other side of the Earth. The closest block of ice was only three thousand meters away from this one. Because it rotated about its minor axis, in their eyes, such a rotation had a breathtaking momentum, as though they were three tiny ants watching a crystalline skyscraper collapsing over and over again. Due to gravity, these two ice blocks would eventually crash into each other. The light-filtering membranes would rupture and the blocks of ice would disintegrate. The smashed blocks of ice would quickly evaporate in the sunlight and disappear. Such collisions had already happened twice in the ring of ice. This was also why this block was the first block of ice to be forced back.
First, an astronaut started the driller vehicle. As the drill head spun, crumbs of ice flew out in a cone-shaped spray, twinkling in the sunlight. The driller vehicle broke through the invisible light-filtering membrane. Like a twisting screw, it dug into the ice, leaving a round hole in its wake. Along with the hole that stretched into the depths of the ice, a faint white line could be seen in the ice itself. Once the hole reached the prescribed depth, the vehicle headed out toward another part of the ice. It then bored another hole. At last, it drilled four holes in total. They all intersected at one point deep in the ice.
The astronauts inserted the three waveguides into three of the holes, then inserted the expeller into the wider fourth hole. The expeller tube’s mouth was pointed in the direction of the motion of the block of ice. After that, the astronauts used a thin tube to caulk the gap the three waveguides and the expeller tube left against their holes’ walls with a fast-sealing liquid to create a good seal. Finally, they opened the parabolic reflectors. If the initial phase of ocean reclamation employed the latest technology, it was these parabolic reflectors. They were a miracle created by nanotechnology. Folded up, each was only a cubic meter. Unfolded, each formed a giant reflector five hundred meters in diameter. These three reflectors were like three silver lotus leaves that grew on the block of ice. The astronauts adjusted each waveguide so that its receiver coincided with the focal point of its reflector.
A bright point of light appeared where the three holes intersected deep in the ice. It seemed like a tiny sun, illuminating within the block of ice spectacular sights of mythic proportions: a school of silver fish, dancing seaweed drifting with the waves … Everything retained its lifelike appearance at the instant it was frozen. Even the strings of bubbles spat from fishes’ mouths were clear and distinct. Over one hundred kilometers away, inside another ice block being reclaimed, the sunlight that the waveguides led into the ice revealed a giant black shadow. It was a blue whale over twenty meters long! This had to be the Earth’s seas of old.
Deep in the ice, steam soon blurred the point of light. As the steam dispersed, the point changed into a bright white ball. It swelled in size as the ice melted. Once the pressure had built up to a predetermined level, the expeller mouth cover was broken open. A violent gush of turbulent steam exploded out. Because there were no obstructions, it formed a sharp cone that scattered in the distance. Finally, it disappeared in the sunlight. Some portion of the steam entered another ice block’s shadow and condensed into ice crystals that seemed like a swarm of flickering fireflies.
The deceleration propulsion system in the first batch of one hundred blocks of ice activated. Because the blocks of ice were so massive, the thrust the system produced was, relatively speaking, very small. As a result, they needed to orbit fifteen days to a month before they could slow the blocks of ice down enough for them to fall into the atmosphere. Later, reclaiming ice blocks that rotated was much more complicated. The propulsion system had to stop the rotation first, then slow down the block of ice.
Before the blocks of ice entered the atmosphere, astronauts would land on them again to recover the waveguides and reflectors. If they wanted to force all two hundred thousand blocks down, this equipment had to be reused as much as possible.
Ice Meteors
Yan Dong and members of the Crisis Committee arrived together at the flatlands in the middle of the Pacific Ocean to watch the first batch of ice meteors fall.
The ocean bed of former days looked like a snowy white plain, reflecting the intense sunlight—no one could open their eyes unless they were wearing sunglasses. But the white plain before them didn’t make Yan Dong think of the snowfields of her native Northeast because, here, it was as hot as hell. The temperature was near fifty degrees Celsius. Hot winds kicked up salty dirt, which hurt when it hit her face. A hundred-thousand-ton oil tanker was in the distance. The gigantic hull lay tilted on the ground. Its propeller, several stories tall, and rudder completely covered the salt bed. An unbroken chain of white mountains stood even farther in the distance. That was a mountain range on the seafloor humanity had never seen until now. A two-sentence poem came to Yan Dong’s mind: The open sea is a boat’s land. Night is love’s day.
She laughed bitterly then. She’d experienced this tragedy, yet she still couldn’t shake off thinking like an artist.
Cheers erupted. Yan Dong raised her head and looked to where everyone was pointing. In the distance, a bright red point had appeared in the silver ring of ice that traversed the sky. The point of light drifted out of the ring. It swelled into a fireball. A white contrail dragged behind the fireball. This contrail of steam grew ever longer and thicker. Its color became even denser, even whiter. Soon, the fireball split into ten pieces. Each piece continued to split. A long white contrail dragged behind every small piece. This field of white contrails filled half the sky, as though it were a white Christmas tree and a small, bright lamp hung on the tip of every branch.…
Even more ice meteors appeared. Their sonic booms shook the earth like rumbles of sp
ring thunder. As old contrails gradually dissipated, new contrails appeared to replace them. They covered the sky in a complex white net. Several trillion tons of water now belonged to the Earth again.
Most of the ice meteors broke apart and vaporized in the air, but one large fragment of ice fell to the ground about forty kilometers from Yan Dong. The loud crash shook the flatlands. A colossal mushroom cloud rose from somewhere in the distant mountain range. The water vapor shone a dazzling white in the sunlight. Gradually, it dispersed in the wind and became the sky’s first cloud layer. The clouds multiplied and, for the first time, blocked the sun that had been scorching the earth for five years. They covered the entire sky. For a while, Yan Dong felt a pleasant coolness that oozed into her heart and lungs.
The cloud layer grew thick and dark. Red light flickered within it. Maybe it was lightning or the light from the continuous waves of ice meteors falling toward the earth.
It rained! This was a downpour so heavy it would have been rare even in the Oceaned Days. Yan Dong and everyone else there ran around screaming wildly in the storm. They felt their souls dissolve in the rain. Then they retreated into their cars and helicopters because, right now, people would suffocate in the rain.
The rain fell nonstop until dusk. Waterlogged depressions appeared on the seafloor flatlands. A crack in the clouds revealed the golden, flickering rays of the setting sun, as though the Earth had just opened its eyes.
Yan Dong followed the crowd, stepping through the thick salty mud. They ran to the nearest depression. She cupped some water in her hands, then splashed that thick brine on her face. As it fell, mixed with her tears, she said, choking with sobs:
“The ocean, our ocean…”
Epilogue
TEN YEARS LATER
Yan Dong walked onto the frozen-over Songhua River. She was wrapped in a tattered overcoat. Her travel bag held the tools that she’d kept for fifteen years: several knives and shovels of various shapes, a hammer, and a watering can. She stamped her feet to make sure that the river had truly frozen. The Songhua River had water as early as five years ago, but this was the first time it had frozen, and during the summer, no less.
