Further: Beyond the Threshold

by Chris Roberson

  How had there been no hint of this in the chamber I’d just left?

  I turned, and through the doorway, I could see the table and the confusion of chairs, just as we’d left them. But the metallic frame of the doorway—and I saw now that there was no door, just the frame—was surrounded on both sides by nothing but empty air. No walls. I stepped to one side and could see that the doorframe was freestanding, with nothing behind it but open space. No table, no chairs, no domed chamber.

  My confusion was no doubt evident to the silver eagle, which had lifted into the air and was now circling overhead.

  “Allow me to apologize,” the escort said, landing once more on my shoulder. “I should have explained. We have just transited a threshold, one terminus of which is located in the orbital habitat of Pethesilea, the other of which is here in Central Axis on Earth.”

  “Threshold?” My mind was racing, but my mouth was moving slow in catching up.

  “A flat-space, traversable wormhole connection within a frame containing fragments of cosmic string. The negative mass of the frame is balanced by the positive mass of the mouth itself, leaving the threshold with an almost-zero mass.”

  “Wormhole,” I repeated, seemingly unable to string two or more words together.

  “If you’ll observe,” the escort pointed with its silver beak, “the other thresholds of Central Axis, all part of the threshold network.”

  I stepped back from the doorframe—the wormhole—and saw a profusion of other similar structures, of varying sizes, arranged in concentric circles throughout the enormous space. The largest towered overhead, while the smallest were so narrow I’d have had trouble squeezing through, but most were the same size—that of a respectably large doorway, perhaps three meters tall and two wide.

  “There’s a…network of these things?” I was slowly regaining basic communication skills as I tried to process what the silver eagle had told me.

  “The threshold network can be described as analogous to a metropolitan transportation system, such as subways on Original Earth.” The escort spoke matter-of-factly, like a guide at a tourist destination. “The thresholds to the most populous and powerful of worlds and habitats link directly to the Central Axis on the megastructure Earth, while worlds with lower populations or levels of power are linked to satellite axes that are themselves linked to the Central Axis. Less powerful worlds still are linked to even smaller satellite axes, which themselves are linked only to larger satellites. And so on.”

  A web of traversable wormholes, accessible from Earth. The ability to walk from one world to another in a matter of steps. My mind reeled.

  The eagle still perched on my shoulder, I shuffled barefoot to the next of the metal frames in the circle, indistinguishable in almost all respects from that through which we’d just passed.

  I glanced within and saw only purple skies beyond.

  “Where…? Where does it lead?”

  “To a planet in orbit around the triple-star system known in your era as Algol ABC, or Beta Persei. It lies roughly 92.8 light-years from Sol.”

  The distance was so large I had trouble fitting it inside my head. I swallowed hard and had a thought.

  “Tell me,” I began, a slight quavering in my voice, “is there a…threshold that leads to Alpha Centauri B?”

  “Naturally,” the silver eagle said, and pointed to one side with its beak. “If you would only proceed thirty meters in that direction…”

  I walked, though don’t really remember how long it took or what thoughts might have gone through my head as we went. I remember only passing what appeared to be the upright sides of a threshold, but lacking the crosspieces at top or bottom.

  Seeing my gaze linger on the object, the escort explained.

  “That was once the threshold that led to the home world of the Iron Mass, the dismantled elements left as a memorial to those unpleasant days.”

  A question began to formulate in my mind, but before it reached escape velocity, passing beyond the reach of the torpor that gripped my thoughts, the escort said, “We have reached the threshold to the star you know as Alpha Centauri B.”

  I stood there, motionless, looking up at the silver frame before me. It was a twin to the one I’d walked through, though instead of a darkened room or a purple sky, I saw a cloud-flecked stretch of blue heavens arching over a gently rolling field of green, dotted here and there with splashes of color, which seemed familiar strains of flowers to my untrained eye.

  “There is no cost associated with transiting this particular threshold, sir, if you’d like to step through.”

  I took a single step forward and paused. The eagle on my shoulder was still near weightless, but I could feel the press of thousands of long years weighing on my back.

  My crewmates and I had sacrificed any kind of normal life, on Earth or one of the colonies of the Sol system, to brave the interstellar gulfs and be the first humans to reach another star. Had our mission been successful and we returned to Earth as planned, we’d have been away the better part of a century, while everyone who might ever have known us aged and died. As it happened, we were gone much longer than that, which only poured salt into the wound.

  Taking a deep breath, I stepped forward, and as I passed beneath the frame, my bare feet fell on cool, soft grass.

  There was a slight, warm breeze, and off to my right I saw a cluster of strangely shaped buildings rise above a swell of land. They resembled organic growth more than architecture, bulbs balanced delicately atop narrow stalks. Overhead shone a yellow main sequence star, only slightly larger in the sky than the sun seen from Earth’s surface, a close cousin to Sol.

  I had joined the UNSA to explore, to expand the frontiers of the human experience. Like the rest of the crew of Wayfarer One, I had happily sacrificed anything like a normal existence to strike out for a new world, a possible new home for humanity. Now I had learned that while I slept long millennia, humanity had already expanded far beyond my wildest imaginings, and I found myself left with one question: What would I do now? I felt a dull ache deep within, realizing that the frontier had long ago retreated far beyond my reach.

  “What is the name of this planet?” I asked, my eyes tracking the horizon.

  “The closest approximation in Information Age English is Haven, but the first settlers here in the Second Space Age called it Ramachandra’s World.”

  It took a moment for that to sink in.

  “What did you say?”

  “It’s only natural, sir,” the silver eagle said. “Yours is one of the best known voyages of exploration in human history, ranked with that of the Polynesian mariners or of James Cook or Yuri Gagarin. That you didn’t reach your mission’s destination does not detract from the attempt itself.”

  I turned my head, looking directly into the smooth eyes of the metal bird. “Except I have reached my destination now, haven’t I?”

  The escort nodded slowly, and I fancied I saw something like amusement in its metal expression.

  “A journey of light-years, no more difficult than moving an alter from one world to another.”

  “Sir?”

  “Never mind.”

  I turned and stepped back through the threshold.

  My hand didn’t make the inventory control gesture, but only because I consciously suppressed the reflex. Still, I said aloud, “I hope I didn’t leave anything behind I’ll need,” patting the sides of my robe, feeling naked and exposed.

  “You needn’t worry, sir. The only things that can’t be transported through a threshold are cosmic string fragments themselves. The negative energy of the fragments collapses the wormhole so that thresholds have to be dragged into place at sublight speeds.”

  “Well,” I said, and then stopped, again at a loss for words. “I suppose I’ll keep that in mind.”

  “Shall we go to the quarters prepared for you, sir? There may be more suitable attire for you there.”

  “Why not?” I said, and honestly couldn’t think of
anything else I might do.

  It took a few moments to thread our way through the concentric circles of thresholds, toward the nearest wall and an exit to the outside. The exit was a more traditional door, meters tall and immense, but with panels that slid open and closed. As we approached the opening doors, a small crowd gathered, most of them seeming to be normal varieties of human, but with an odd mixture of man, machine, and animal scattered here and there. My head was so full of wormholes that I scarcely noticed them, and I absently assumed them to be some sort of commuters, but I noticed after a moment that many had begun pointing in my direction, staring and whispering quietly to one another in strange languages.

  Finally, we passed through the open doors and into the bright daylight beyond. And I almost collapsed onto the ground, struck by an overwhelming disorientation.

  Overhead, past a sky of startling blue, I saw the indistinct image of curving farmland and cities, and high over the horizon were towering mountains topped with snow, pointing in my direction like accusing fingers. I was not standing on a planet’s surface, but seemed instead to be on the inside of a hollow sphere, looking up at the opposite interior.

  “Madar chowd,” I swore.

  “Well, sir,” the escort chimed in my ear, “after all, I did say that Earth isn’t quite the world you remember.”

  EIGHT

  In 2145 CE, right around the time I was joining the Bharat Scouts, the movie Destroyer was released to theaters. It was a slightly fictionalized account of the Impact, which killed millions, destroyed entire cities, toppled at least one nation, and sent dozens of others into decades-long economic depressions, and ravaged Earth’s environment for a century or more.

  In the movie’s opening scenes, computer-generated models of old and long-dead Hollywood and Bollywood stars portrayed the three scientists at the NASA-funded University of Hawaii Asteroid Survey from Kitt Peak National Observatory in Arizona who, on June 19, 2004, were the first to learn of the asteroid’s existence. An avatar of Raoul Bova was cast as Fabrizio Bernardi, a young Roy Scheider was selected to portray David J. Thoel, and the recently departed Joos Diamond Fortunate assayed the role of Roy A. Tucker. In a dramatic moment, having just looked up from the data scrolling across their monitors, the three scientists name the newly discovered asteroid after a mythology figure depicted in an illustrated encyclopedia lying open on a nearby desk.

  It’s all terrifically portentous and “important,” but sadly, it’s complete fiction. In real life, they reportedly borrowed the name from the villain on a second-rate science fiction television program.

  Apophis was originally the Greek name of the Egyptian god Apep, the Destroyer, who dwelt in the eternal darkness of the underworld of the Duat, from which he came forth nightly in an attempt to destroy the sun. The asteroid, then, was classified Asteroid 99942 Apophis, or Asteroid Apophis, or just plain Apophis. Or, as it came to be known by the whole world a few short years later, the Destroyer.

  Did the scientists know what kind of sympathetic magic they were working when they named a chunk of rock 320 meters in diameter after a demon bent on devouring the sun? Massing out at 4.6 x 10^10 kg, or roughly eight times the mass of the Great Pyramid of Giza, when the Destroyer struck Earth on April 13, 2036, the impact released energy equivalent to 870 megatons (or 65,500 times the atomic bomb dropped on Hiroshima) as the asteroid struck Los Angeles at a velocity of 12.59 km/s.

  Those killed in the initial impact were the lucky ones. As debris from the Destroyer rained back down to Earth over a range of thousands of kilometers, the city of Los Angeles reduced to a crater filled with ash and shocked quartz, the sky was blackened over much of Earth. The asteroid had accomplished what its mythological namesake could not as darkness fell.

  The United States of America, unable to recover from the devastation, balkanized in the years following the Impact. The state of Utah withdrew from the union to become the independent nation of Deseret. Northern California, Oregon, and Washington became Pacifica and petitioned to join Canada. Florida became the Archdiocese of Florida, a Catholic Cuban state. The United States continued to exist as a sovereign state and political entity well into the next century, but its borders were much smaller, and it was no longer a player on the world stage. Worse, a sizeable percentage of Americans took the Impact as proof of the wrath of an angry god, punishment for a godless, secular nation. A flight of intellectuals and artists followed in the late 21C as the diminished USA became more and more repressively fundamentalist. Many of the dispossessed settled in New Zealand or Australia, India, or England—any developed nations with large English-speaking populations—my own paternal grandparents among them.

  In the rest of the world, the Impact was felt in different ways. Already in the late 20C and early 21C it was felt that Earth itself had turned against humankind somehow, lashing out more and more every year with earthquakes and floods and fires, but now even this fragile environment was no refuge against the dark. Following the Impact, humankind looked to space, not as an abstract source of wonder, something to be gazed at romantically or studied by lab-suited scientists in labs, but as a source of danger, as a looming threat.

  The first move was to establish a network of asteroid defense systems, sufficient to deflect any subsequent meteors or asteroids that might draw near Earth. Second, the nations of Earth began a concentrated and coordinated effort to mine the moon, the asteroids, and other celestial bodes of the solar system, to meet the growing energy demands of Earth, which would be long in recovering from the environmental and economic effects of the Impact.

  In time, with the consolidation of the United Nations, the chartering of the UNSA, and the gradual colonization of the asteroid belt, Mars, and the Jovian moons, space changed once more, becoming, for the first time, a possible new home for humankind. But still there lingered, in the back of every mind, the thought that, one day, the heavens might again open up and rain down destruction on Earth.

  NINE

  Gazing up at the landscape curving overhead, I thought of Charlton Heston’s Taylor, standing before the ruined Statue of Liberty. The character, seeing the charred remains of a once proud culture, immediately assumes the destruction came at man’s own hand. For contemporary viewers, there was little doubt that Armageddon would be nuclear.

  Growing up in the shadow of the Impact, for me death was always expected from above. Fictions about extinction-level events, asteroids the size of moons striking Earth, were common when I was young.

  Each culture throughout history, I suppose, has always chosen its own apocalypse, its own end of the world to fear. All of them, as it happens, were wrong. Man was responsible, in the end, but he did it on purpose.

  “As a site for long-term habitation,” the escort explained, “Earth simply became too erratic.”

  We were riding a moving sidewalk down a broad avenue. Buildings rose on either side, in strange and unlikely forms, while oddly configured air-vehicles filled the skies. There were other pedestrians around us, but I was still too distracted to pay them much attention. I felt a deep sense of vertigo, with mountains and oceans looming far overhead, indistinct in the blue sky like a ghostly moon seen by daylight, and had to resist the temptation to wrap my arms around a post or a tree and hold on for dear life.

  “Changes to the planet’s environment, resulting from widespread deforestation and urbanization, the introduction of pollutants to the atmosphere, and so on, compounded to unbalance the climatological system, such that Earth’s weather patterns became increasingly unpredictable, the variations swift and violent.”

  I’d seen erratic weather and the results of climate change firsthand. Long before I was born, the sea levels rose high enough that the waters swallowed whole nations. When the sea reclaimed the flatlands, the Dutch became homeless. A flotilla of seagoing vessels followed the court of King Pieter on his decommissioned cruise liner for years. In the late 21C, with the death of his father, the heir apparent King Christian had purchased a number of castoff
NASA reusable launch vehicles and migrated to Ceres, the largest rock in the asteroid belt, which he claimed as the new Dutch homeland. They were a strange, foul-smelling crew, the Dutch belters, but they always threw the best parties, and always had the best stuff to smoke.

  “So then…what?” I asked, shaking my head. “Environmental changes destroyed the planet?”

  I glanced at the silver eagle on my shoulder that regarded me with a metallic expression of confusion.

  “Destroyed?” it repeated. “Well, no, of course not. The planet could have continued to exist quite happily—erratic weather patterns or no. The problem came in that the inhabitants of the planet found it increasingly problematic to remain. When continued warming caused the destabilization of methane hydrate deposits at the bottom of the ocean, the gigatons of methane released increased surface temperatures to levels higher than any seen on Earth in four billion years.”

  I shuddered. I was a student at the university when the rainforests began to catch fire, but I’d always hoped that we’d somehow be able to reverse the trend. Apparently, I was wrong.

  “The planet was abandoned for some time, I’m afraid,” the escort continued, “the inhabitants migrating through flatspace to neighboring worlds and colonies. There was some considerable nostalgia for Original Earth, though. And Sol remained at the center of human space. So eventually, sentiment was such that funds were raised to rehabilitate the ancient cradle of humanity. One proposal was to terraform the planet, resetting the ecosystem and starting over from scratch. That was rejected as too time-consuming by the impatient investors. Instead, it was decided to dismantle and reconstruct Earth into a planetary-scale megastructure.”