by Cixin Liu
That night, one could feel the faint tremors all the way to Urumchi as the ship dug into the Earth.
The first five Setting Sun ships successfully carried out their missions into the deep strata of the Earth and all returned safely to the surface. On its dig, the Setting Sun V set a new depth record for humanity, tunneling its way almost a full 2,000 miles below sea level. The Setting Sun VI had no intentions of breaking this record. Geophysicists had determined that the boundary between the Earth's mantle and core could be found at a depth of roughly 2,100 miles. The scientists called it the “Gutenberg Discontinuity”. Once through this boundary, one would enter Earth's liquid iron-nickel core. This also meant that the density of the surrounding matter would abruptly and exponentially increase beyond this boundary. The design specifications of the Setting Sun VI did not allow it to navigate through densities of such magnitude.
At first, the mission of the Setting Sun VI progressed without a hitch. In only two hours, the ship had penetrated the boundary between Earth's crust and its mantle, the Mohorovicic Discontinuity. Then it stopped for five hours on the sliding surface of the drifting continental plate before beginning its 1,800-mile journey through the Earth's mantle. Space is a lonely place, but at least astronauts can see the infinity of the universe and majesty of the stars; stratonauts in their sub-ships, on the other hand, had nothing but the sensation of endlessly increasing density to guide them. All they could glean from their rear-mounted holographic screen was the blinding glare of seething magma following in their ship's wake, instantaneously closing the tunneled space behind their ship's stern. A stratonaut once described the experience, saying they just needed to close their eyes to see the onrushing magma gather behind them, pressing down and sealing them in. It was a sensation that kept every stratonaut aware of the immensity of ever-denser material pressing down upon them, tormenting them with a feeling of intense oppression that was hard for those on the surface to comprehend. No one was spared these intense attacks of claustrophobia.
Even as it descended, the Setting Sun VI’s research work was above and beyond the mission targets. The ship was traveling at roughly 10 miles an hour, making its journey to its target depth a matter of 20 hours. Fifteen hours and 40 minutes after its launch, however, the ship's descent was interrupted by the shrill sound of an alarm. The subsurface radar had picked up a sudden increase of density, jumping from 393 pounds per cubic-foot to 593 pounds. The material the Setting Sun VI was suddenly faced with was no longer silicates but a metallic substance primarily composed of nickel and iron. Furthermore, it was no longer solid, but liquid. Even though the Setting Sun VI had only reached a depth of 1,500 miles below the surface, all signs seemed to point to one chilling conclusion: They had broken into the Earth's core!
Later it was discovered that they had chanced upon a fissure in the Earth's mantle that cut straight to the core. This fissure was completely filled with the highly pressurized liquid iron-nickel of the Earth's core. In the path of the Setting Sun VI, the Gutenberg Discontinuity reached up to a depth of 1,500 miles! The ship turned on the spot, attempting to escape the fissure. And that was when it happened: The neutron material of the ship's hull easily held up as the pressure suddenly increased to a massive 11,500 tons per square-inch, but the ship itself was composed of three parts, a front-facing fusion engine, a central cabin, and a rear-mounted drive engine. When the ship turned, the fusion engine separated from the cabin, snapped off by density and pressure that well-exceeded the ship's operating limits. The pictures broadcast by the neutrino communicator of the Setting Sun VI clearly showed the fusion engine splitting from the hull, only to be instantly swallowed by the crimson glow of the liquid metal.
A subterranean ship's fusion engine fired a super-heated jet that cut through the material in front of the vessel. Without it, the drive engine could not push the Setting Sun VI even an inch through the earth. And while the density of the Earth's core was truly terrifying, the density of the neutron material of the Setting Sun VI was even greater. As the buoyant force of the liquid nickel-iron was less than the vessel's weight, the Setting Sun VI sank, plummeting ever further down into the Earth.
A century and a half after landing on the Moon, humanity had mastered the technology needed to reach Saturn. It was planned that the hurdle between mantle and core be leapt in a similar time-frame. Now, a sub-ship had accidentally entered the core and just like an off-course Moon rocket would have drifted into the depths of space in the twentieth century, not even the slightest hope of rescue remained.
Fortunately, the hull of the ship's cabin was sturdy and its neutrino communication system allowed it to maintain uninterrupted contact with the control center on the surface. In the following year, the crew of the Setting Sun VI continued with its work, prying much valuable data from the Earth's core and sending it to the surface. Encased as they were in thousands of miles of rock, the crew was obviously cut from all air and any life. They were bereft of space, floating in temperatures reaching 9,000 degrees and surrounded by pressures that could crush carbon to diamonds within seconds! Only neutrinos could escape the massive density of the material in which the Setting Sun VI was entombed. The ship was thoroughly trapped in a giant furnace of molten steel. In this world, Dante's Inferno would have been paradise; in this world, what could life mean? How could anyone even begin to describe it?
The immense psychological pressure bearing down on the crew of the Setting Sun VI cracked nerves and percolated into the deepest layers of their minds. One day, the ship's geological engineer woke, leapt out of bed and without warning unsealed the nearest insulated gate protecting the cabin. Even though this was only the first of four, it opened the way for a wave of incandescent air that instantly burned him to charcoal. The ship's commander, who was in the cabin at the time, immediately closed the insulated gate, managing to avert the outright destruction of the Setting Sun VI by the skin of his teeth. He himself, however, suffered severe burns. He had barely completed his final logbook entry, before succumbing to his injuries.
From that moment on, only a single person remained aboard the Setting Sun VI, trapped in the deepest recesses of the planet.
By now, the sub-ship was in an area of almost total weightlessness. The ship had sunk to a depth of 4,000 miles, reaching the deepest point imaginable. And so the last remaining stratonaut of the Setting Sun VI became the first person to reach the Earth's core.
In the heart of the planet she lived in a cramped cockpit of barely a hundred square-feet. Her only reprieve was the fact that the ship was equipped with a pair of remote-sensing glasses that allowed her to maintain at least some sensory contact to the surface world far, far above. This lifeline, however, would hardly last forever as the energy of the ship's neutrino communication system quickly depleted. Already, the energy did not suffice to maintain the transmission of the ultra high-speed data the remote-sensing glasses required. The system had lost contact three months ago, just as I was taking the plane back to the Aerospace Center from the Taklamakan. At the time, her eyes had been in my luggage.
Because I had put them there.
That sunless, drizzly dawn over the grassland had been her last sight of the surface world.
From then on, the Setting Sun VI had only been able to maintain communication with the surface via voice and data transmissions. But in the dead of night these systems, too, had recently failed, leaving her forever alone, sealed away in the Earth's core.
The outer neutron material shell of the Setting Sun VI was strong enough to withstand the core's pressure and the ship's life-support systems could run for another 50 to 80 years, so she would remain alive, until the end, in her tiny one-hundred square-foot world at the center of the Earth.
I hardly dared imagine her final farewell to the surface world, but when the Director played the recording, it exceeded my wildest expectations. The neutrino beam to the surface had already been very weak and her voice faded in and out, but even as it did, it conveyed nothing but calm and peac
e.
“…have received your final advisement. From now on, I will devote all my efforts to my work on these research projects. In the future, maybe many generations from today, a core-ship will perhaps find the Setting Sun VI and dock with it. Someone will then perhaps enter here. I can only hope that the material I leave behind will then be of some use. Please, rest assured; I have made a life for myself here. I now no longer feel constrained or sealed away. The entire world surrounds me. All I need to do to see the vast Taklmakan above is to close my eyes, and then I can clearly see every last little flower I named. But now, I must bid you farewell.”
CHAPTER
3
The World, Clear as Crystal
Many years have passed and I have visited many places. Everywhere I go, I lie upon the earth. I have lain on a beach on the island of Hainan, on the ice- and snow-covered soil of Alaska, in the middle of the Siberian White Taiga, on the burning sands of the Sahara…
Every time, the planet below opened to my mind's eye, making the Earth clear as crystal. Four thousand miles below me, anchored to the very heart of this immense, translucent sphere, I could see the Setting Sun VI. And I could feel her heartbeats echo through thousands of miles, right to me. I imagined the golden light of the Sun and the silvery glow of the Moon shining down to the planet's core and in my heart I could hear her humming Clair de Lune and her soft voice saying,
“... so beautiful. It is music of another kind...”
There was one thought that always soothed my soul: Even if we were worlds apart, I would never be any farther from her.
The Longest Fall
PREFACE
As the Earth's natural resources dwindled and its environment deteriorated, the world turned its gaze to Antarctica. This brought with it many changes, elevating the two rapidly rising powers in South America to a position on the pinnacle of world politics that reflected their strength on the soccer field. It also relegated the Antarctica Treaty System to the dustbin of history, its promises worth less than the paper on which they were written. These developments were accompanied by a triumph of human reason in another field: The complete eradication of all nuclear weapons. In a world without nuclear arms, the world's nations could begin their struggle for Antarctica free from the fear of the shadow of a thermonuclear apocalypse.
CHAPTER
1
A New Solid State
Making his way through the vast cave, Shen Huabei was surrounded by darkness. Had it not been for the heat radiating from the ground below, he could have easily imagined himself back on the plains, shrouded in the dark of a starless night. The heat, intense enough to draw sweat from his feet despite the thick layers of insulation provided by his boots, was one remnant of the recent nuclear explosion. Where he walked, the rocks melted by the explosion had already completely re-hardened and mostly cooled. A bit further in, he could see part of the cave wall that remained hot, emanating a faint crimson glow. In Huabei's mind it was the dim light of dawn, reaching over the far horizon of his night-covered plain.
Huabei was not alone. On his left his wife, Zhao Wenjia, was making her way through the cave, while his eight-year-old son, Shen Yuan, was merrily bouncing along in front of them. Jumping and flailing, he seemed completely oblivious to the cumbersome weight of his anti-radiation suit. They were joined by the members of the UN nuclear inspection team. All around them, the team's helmet lamps cast bright beams, piercing the surrounding black.
The complete destruction of the world's nuclear weapons was being achieved by two means: Dismantlement and subterranean detonation. This cave was one of sites where China carried out its subterranean detonations.
As they delved deeper, the head of the nuclear inspection team, Professor Kamensky, began to make his way to the front of the group and toward Huabei and his wife. As he drew closer, his helmet lamp threw long, swaying shadows off the three of them. “Professor Shen,” Professor Kamensky called out from behind. “Why ever did you bring your wife and son? This is hardly the place for a family excursion.”
Huabei stopped, waiting for the Russian physicist to catch up. “My wife is a geological engineer working for the central command of the Eradication Operation,” he noted genially. “And as for my son; I think he enjoys places like this.”
“Our son has always been fascinated by the strange and the extreme,” Wenjia agreed, more to her husband than the head of the team. Even though her face was partially concealed by the radiation suit's visor, Huabei could still clearly see the unease in his wife's eyes.
“First this hole was as big as our vegetable cellar. Just two explosions and now it is this huge!” the little boy in front of them called out, skipping along. “I think the bomb's fireball is just like a buried baby; it cries and shouts, stomps and kicks. Now that is a fun baby!”
Huabei's gaze met Wenjia's. He was quietly smiling, but the worry in her expression had only deepened.
“Son, this is the work of eight babies!” Professor Kamensky noted with a laugh. He then addressed Huabei in somewhat more sober tones. “Professor Shen, I actually wanted to talk to you about something else; this time, we detonated the warheads of eight submarine-launched SL-2's, each one with a payload of one hundred kilotons. We arranged the warheads in a square on the frame –”
“And your question is?” Huabei interrupted.
“Before the detonation, we could clearly see a white sphere positioned right in the center of the frame on the monitors,” Professor Kamensky explained.
Huabei again stopped and now fully turned to face Professor Kamensky. “Professor, the Eradication Treaty only stipulates minimums for what can be placed underground; as far as I know, it says nothing about additions. The explosion's yield was monitored and successfully verified by no fewer than five different monitoring systems. Everything else is rather irrelevant, wouldn't you say?”
Professor Kamensky nodded. “That is why I am only raising it after the detonation; I was merely curious.”
“I presume that you have heard of sugarcoating?” Huabei stated more than asked.
The last word could have been a powerful incantation, stopping everyone in the cave frozen in mid-step, the previously bobbing beams of the helmet lamps suddenly locking in place. Their exchange had to be transmitted through the radiation suits' wireless communication system and so everyone in the cave had clearly heard Huabei's words.
Moments of silence followed, and then the members of the nuclear inspection team all began to descend upon Huabei. Everyone in this select group, no matter what part of the world they hailed from, was a luminary in the field of nuclear weapons research and they had all clearly heard.
“Does it really exist?” an American asked, staring at Huabei.
The latter just nodded.
It was said by those who would know, that in the middle of the last century, immediately after learning of China's first nuclear weapons test, Mao Zedong had asked, “Was that a nuclear explosion?” It is unclear whether he had intended it that way, but his question showed a good grasp of the matter.
The key piece of technology in a nuclear fission bomb is the implosion pressure acting toward its center compressing the fissile materials in its core. This implosion force is generated by setting off conventional explosives tightly packed around the bomb's core. The compression forces exerted by this implosion in turn causes the fissile materials to reach critical mass and so spark a violent chain reaction that initiates the nuclear explosion. All of this happens in the millionth of a second, demanding that the implosion forces acting on the fissile materials be engineered to incredibly exacting standards. Even the tiniest irregularities can prevent the fissile materials from reaching critical mass before they are scattered by the explosion. Such mishaps end in nothing more than a conventional chemical explosion. From the very beginning, researchers used extremely complicated mathematical models to design the explosive yields for the compression core. In recent years, various methods of using cutting-edge technology to produ
ce ever more perfect compression cores had been explored. “Sugarcoating” was one of these methods.
The “sugarcoating” itself was a type of nano-material that would cover the fissile material of a nuclear bomb around which the conventional explosives would then be packaged. The sugarcoating would automatically cause any pressures acting on it from the outside to be evenly distributed along its inside. As a result, even if the conventional explosives produced uneven pressures, they would all be leveled out by the sugarcoating, making the conventional explosive produce a perfect implosion.
“You saw the white sphere in the middle of the eight nuclear warheads. That was an alloy packaged in sugarcoating,” Huabei explained. “During the nuclear explosion it was subjected to enormous pressures. We plan to conduct research on it during the entire eradication process. After all, this is a rare opportunity. Once all nuclear weapons have been destroyed, it will be very difficult to generate such fast-acting and powerful compression forces. It will be very interesting to see what the effects will be and what changes the test material will undergo under these enormous pressures. We hope that with this research, we will be able to afford sugarcoating technology the prospect of a bright future in civilian hands.”
Considering the possibilities, one UN official said, “You should encase graphite in sugarcoating; then we could produce a large diamond with every explosion. It might make the very costly business of eradicating nuclear weapons a rather profitable endeavor.”