THE KILLING STAR
Had Mary Shelley or Edgar Allan Poe been born into the mid-twentieth century, they would never have had to invent horror.
For the Japanese scientists who first ventured into the still-radioactive hypocenters of Hiroshima and Nagasaki trying to understand what had occurred, the most fearsome deaths were the quickest. On a bridge located in central Hiroshima, a man could still be seen leading a horse, though he had utterly ceased to exist. His footsteps, the horse’s footsteps, and the last footsteps of the people who had been crossing the bridge with him toward the heart of the city were preserved on the instantly bleached road surface, as if by an accidental new method of flash photography.
Only a little farther downriver, barely 140 steps from the exact center of the detonation, and still within this same sliver of a second, women who were sitting on the stone steps of the Sumitomo Bank’s main entrance, evidently waiting for the doors to open, evaporated when the sky opened up instead. Those who did not survive the first half-second of human contact with a nuclear weapon were alive in one moment, on the bank’s steps or on the streets and the bridges—hoping for Japan’s victory or looking toward defeat, hoping for the return of loved ones taken away to war, or mourning loved ones already lost, thinking of increased food rations for their children, or of smaller dreams, or having no dreams at all—and then, facing the flash point, they were converted into gas and desiccated carbon and their minds and bodies dissolved, as if they had been merely the dream of something alien to human experience suddenly awakening. And yet the shadows of these people lingered behind their blast-dispersed carbon, imprinted upon the blistered sidewalks, and upon the bank’s granite steps—testament that they had once lived and breathed.
On that sixth day of August 1945, no one who conceived, designed, or assembled the Hiroshima bomb knew where uranium nuclei came from, or what science had actually achieved. Not Oppenheimer or Urey, Alvarez, or even Einstein would have believed that they had resurrected something from the remote past, from a time and a place seldom encountered in human thought. Each of the uranium-235 atoms at the bomb’s core had been forged more than 4.6 billion years earlier, in the hearts of supernovae. The core was assembled from the ash of stars that had lived and died long before the oldest mountains of the moon were born. Mined and refined to better than 83 percent purity, and brought together in precisely the right geometry, the primordial remnant of Creation was coerced to echo, after ages of quiescence, the last shriek of an imploding star. In all its barest quantum essentials, what happened above Hiroshima that morning—and three days later in Nagasaki, in a separate, plutonium cauldron, filled with the by-products of a uranium reactor—signified the brief reincarnations of distant suns.
None of the men who worked this strange alchemy understood yet that the carbon flowing within their veins was, like uranium, the dust of the stars. Nor did they know that the nuclei of carbon and uranium could possibly conceal anything much smaller than the diameter of a proton. Indeed, Einstein and Oppenheimer refused even to acknowledge that such quantum worlds existed. They therefore did not know what neutrons were made of or precisely how cracks in space-time—cracks in the universe itself—permitted matter to become energy. So primitive was their understanding that it might have been compared to the thought processes of a Neanderthal discovering napalm. In like manner, the scientists never suspected that the forces they unleashed bridged their day with the origin of the universe and bridged mega-time with the travel time of light across the diameter of a proton. Though they knew next to nothing about how their briefly created echo from the past worked, next to nothing was enough.
INEVITABLY, SOMEONE WAS BOUND to be standing below Point Zero. This peculiar distinction fell to a thirty-five-year-old widow and a half-dozen monks. Mrs. Aoyama had sent her son Nenkai away to school a half hour earlier than usual—which was why history was to claim the boy as the sole surviving resident from the neighborhood. The Aoyama home was attached on one side to a Buddhist temple with which the family shared and maintained a large vegetable garden. By 8:15, Mrs. Aoyama was probably working in the garden with her neighbors, just as she worked with them every morning. If so, no one was nearer the actual zero point, or more openly exposed, than Mrs. Aoyama and the monks.
Overhead, the Dome of Hiroshima’s Industrial Sciences Building pointed straight up into the center of the detonation. The temple garden in which Mrs. Aoyama toiled was located immediately adjacent to what would become known to future generations as "the Peace Dome." During that final split second before Moment Zero, Mrs. Aoyama and the monks lived on the cusp of instantaneous nonexistence, on the verge of dying before it was possible to realize they were about to die. At the moment the bomb came to life, before a globe of plasma could belly down to ground level, the top millimeter of the Dome’s metal cladding would catch the rays from the bomb and liquefy instantly, then flash to vapor. Bricks and concrete, too, were on the verge of developing a radiant, liquid skin.
Unlike the man leading a horse across the nearby "T" Bridge, Mrs. Aoyama could not possibly leave a permanent shadow on the ground. From the moment the rays began to pass through her bones, her marrow would begin vibrating at more than five times the boiling point of water. The bones themselves would become instantly incandescent, with all of her flesh trying simultaneously to explode away from her skeleton while being forced straight down into the ground as a compressed gas. Within the first three-tenths of a second following the bomb’s detonation, most of the iron was going to be separated from Mrs. Aoyama’s blood, as if by an atomic refinery. The top few millimeters of soil, as they converted to molten glass, would be shot through with such high concentrations of iron that, had the greenish-brown layer of glass been permitted to slowly cool, it would have been hidden beneath a sheet of carbon steel; but a slow and stately cooling was not to be. By the time the sound of the explosion reached her son Nenkai two kilometers away, all the substance of his mother’s body, including blood-derived iron and calcium-enriched glass, would be ascending toward the stratosphere to become part of the strange radioactive thunderstorms that were to chase after Nenkai and the other survivors.
On the south side of town, about four city blocks beyond Mrs. Aoyama and the monks, Toshihiko Matsuda was about to leave his shadow on a wall in his mother’s garden. He appeared to be bending down to pick a piece of fruit or to pull out a weed. During the next few milliseconds, the wall behind Toshihiko would be flash-printed not only with his shadow, but also with the ghost images of the plants that surrounded him (and which would provide his skin with some small measure of flash protection). On the wall print, at the moment of the bomb’s awakening, could be seen the shadow of a leaf that had just detached from its vine and, though falling, would never reach the ground.
From the Aoyama and Matsuda house holds to the shrimp boats in the harbor, human nervous systems were simply not fast enough to register how quickly the dawn of atomic death burst toward them on that August morning. In the beginning, it had all unfolded from the realm of nanoseconds. Within the core of the reaction zone, approximately 560 grams (or 1.2 pounds) of uranium-235 began to undergo fission before the compressive, shotgun-like forces designed to start the reaction, and to hold it briefly together, were overwhelmed by forces pushing it apart. Three times heavier than gold (at the moment of compression), every ounce of the silvery, neutron-emitting uranium metal occupied three times less volume than gold. The active, business end of the bomb was therefore astonishingly small, occupying one-third of a golf ball’s volume. The total volume of reacting uranium measured slightly more than two level teaspoons. Within that 1.2-pound, two-teaspoon volume, a sample of almost every element that had ever existed during the entire lifetime of the universe was instantly re-created, and many were just as quickly destroyed.
After only one-hundred-millionth of a second, the core began to expand and the fission reaction began to run down. During this ten-nanosecond interval, the first burst of light emerged with such intensity that even the green and yellow portions of the spectrum could be seen shining through the bomb’s steel casing as if it were a bag of transparent cellophane. Five hundred and eighty meters (1,900 feet) below, no creatures on the ground could see this. During the first ten nanoseconds, light from the core traveled only three meters (about ten feet) in all directions. Fission reactions occurred within time frames so narrow that they bracketed the speed of light. Thus, to anyone located more than ten feet away, the bomb itself, though light was now shining through it, seemed to be hanging perfectly intact above the city. Directly below, Mrs. Aoyama was still alive and completely untouched by the flash.
One ten-millionth of a second later, a sphere of gamma rays, escaping the core at light speed, reached a radius of 33 meters (108 feet), with a secondary spray of neutrons following not very far behind. Between the gamma bubble and the newly formed neutron bubble, electrons were stripped from every atom of air and accelerated toward the walls of the larger gamma sphere. A plasma bubble began to form, producing a thermal shock that spiked hotter than the Sun’s core and glowed billions of times brighter than the surface of the Sun.
Within this atomic flare, X-rays and gamma rays were repeatedly absorbed and scattered, polarized and reabsorbed, to such extent that the rays were as likely to reflect back toward the center of the bomb as away from it. A result of this was that by the time the light reached the ground, the gamma and X-ray bursts would be accompanied by a randomly scattering "sky shine" effect, by which a person shielded from the flash behind, for example, a solid brick wall, could still be pierced by rays emanating from all points of the compass.
During its first millionth of a second, the bubble of light grew to a radius of 300 meters—barely more than six city blocks wide. Though its own expanding dimensions had thinned and cooled the sphere’s outer boundary to only a thousand times the boiling point of water, the temperature was more than three hundred times the number necessary to convert a human body to carbonized mist and incandescent bones. During this same first millionth of a second, and despite all that was happening, the light from the bomb still had not traveled far enough to reach the city. If either Toshihiko Matsuda or Mrs. Aoyama happened to be looking at the blast point at precisely this moment, and were their nervous systems equipped to register one-millionth of a second, the six-block-wide bubble would have appeared to them as an unexploded spear-point in the sky.
Above Matsuda and Aoyama—not merely unseen, but unseeable—the bomb’s neutron surge, though traveling at a substantial fraction of light speed, lagged behind its flash and its gamma burst. From the place where the bomb had been—from its magnetic poles—nuclei of tungsten and iron shot ahead of the neutrons as a spreading shower effect, no longer behaving as if they had ever been part of the structure. Behind them, the outracing spray of neutrons (and to a lesser degree protons and short-lived anti-protons) now became a significant secondary source of prompt, and deadly, radiation.
After one ten-thousandth of a second, the air began absorbing the burst and responding to it. The surrounding atmosphere developed into an expanding gulf of near-perfect vacuum, snapping away from the place where the bomb had been, forming a cave of plasma. Along the cavern’s walls, the neutron spray generated a second great burst of gamma rays. By now the initial flash had traveled to a radius of 30 kilometers (approximately 18 miles), and the light was just beginning to be registered by the rapidly firing nervous systems of mantis shrimps on the bottom of Hiroshima Harbor. Under the hypocenter, the blood in Mrs. Aoyama’s brain was already beginning to vibrate, on the verge of flashing to vapor. What she experienced was one of the fastest deaths in all human history. Before a single nerve could begin to sense pain, she and her nerves ceased to be. Several city blocks away, Toshihiko Matsuda, and the plants that surrounded him, would live a while longer. At a radius of ten city blocks, koi and turtles swimming just below the surface of Hiroshima Castle’s ponds would still be alive the next day—though before they could even begin to flinch or seek deeper water, they were going blind, with the scales and shells on their backs already searing.
Reaction rates were slowing down now—shifting from quantum time frames into the realm of biological time. During the next three milliseconds, a span in which a housefly could execute a single wing flap and start to alter course, the fireball began to form. Initially, it expanded at a hundred times the speed of sound, but by the time its lower surface neared the Hiroshima Dome and the roof of the Matsuda house, 97 milliseconds and 31 wing flaps later, it was down to only a fiftieth of its initial velocity. Near the periphery of the fireball, new fission-generated atoms with very short half-lives were undergoing rapid decay, sending forth a third gamma-ray burst. For all its capacity to cause harm, this third death ray was dwarfed by the heat ray that preceded it and by the gathering storm of a shock wave laced with lightning.
Throughout Hiroshima, one-tenth of a second after detonation, telephone wires and clothing began to send forth vertical columns of black vapor, yet all the buildings of the city still stood. Compared to its beginnings, the shockwave was now sluggish. This slowest of the three major atomic bubbles touched the earth at only twice the speed of sound, scarcely faster than human reflexes.
People required a full thirtieth of a second to register motion; a tenth of a second to flinch. The neural pathways of flies fired and reset, scanned and responded, almost fifty times faster than a human brain. From the fly’s perspective, humans all but stood still, living in a universe of slowed time, much as humans viewed the time frames of garden-variety slugs and snails.
For miles in every direction, flies registered the initial pulse of light less than five milliseconds after it reached the ground, and they were capable of changing course and seeking shade a hundred milliseconds later, during the next thirty wing flaps, or within the average blink or flinch interval of human time.
After 300 milliseconds (or three-tenths of a second), the fireball had reached its maximum potential for inflicting flash burns at a distance; but by then most of Hiroshima’s flies were already sheltering in the shadows of the nearest walls, or under the nearest leaves, or behind the nearest people. The gamma ray sky-shine effect scarcely mattered to them, because a fly’s DNA repair systems were nearly two hundred times more efficient than a man’s.
At three-tenths of a second, the bomb itself was long gone. Everything that followed, as events shifted from bullet-time and fly-time into the time frames humans knew best, signified nothing more than aftershocks.
Akiko Takakura and her friend Asami—though nearer to the bomb than Toshihiko Matsuda and his shadow garden—were located deep within the granite and concrete shell of the Sumitomo Bank when the gamma and infrared bursts started. Except for random shafts of sky shine that came in through windows in the building’s sides, the two women were more or less cocooned against the death rays.
Akiko would always remember how the clock in the main gallery stopped at a quarter past eight, the same time that the big clock atop the Hiroshima University tower had stopped three days earlier. Because the war effort had drained almost all manpower and all spare metal parts, the resources to repair the city’s main timepiece were lacking. During the past three days, Akiko and Asami had joked about how the broken clock tower, frozen seemingly forever at 8:15, underscored the futility of everything. For decades to come, their joke would be clothed in the mantle of prophecy, for in the end repairing the clock or leaving it unrepaired would have made no difference at all. It would only have stopped again at a quarter past eight—like every other clock in Hiroshima.
Akiko and Asami were located only 250 meters (820 feet) from a hypocenter that originated more than twice as high—which placed the shock bubble’s angle of approach almost directly overhead. Women sitting on the steps outside the bank were simultaneously igniting and carbonizing when, about one-tenth of a second before their nerves began to transmit pain, the blast wave intervened. Because the shock-front came down from almost directly overhead, telephone poles and trees, and the vertical supports of the bank were able to resist and were largely bypassed by the forces of compression. Trees and poles and up-thrusting steel beams behaved much like the noses and fins of rocket bombs cutting through supersonic air. Akiko and her friend were spared much by an effect that needed to work only during the first two or three milliseconds of the shock-front’s passage, in order to shield them through the entire five-second bypass of blast and turbulence that followed. The building had literally punched a hole through the advancing wave front, forming a shock cocoon for the two friends (and for a bank manager located in the basement) as the hammerhead of air rebounded outside, spreading away from them.
Akiko felt as if her lungs were being crushed by a surge of dense air. Asami was buffeted and tossed, struck in the back by decorative cladding from a wall that compressed like accordion skin and then erupted as granite shrapnel; but the two friends had been shielded within one of nature’s strangest quirks. The shock-cocoon effect accompanied all major explosive events and tended not to occur where anyone acting on common sense alone would expect survival to be even remotely possible. Sometimes, the safest place to be was nearest the very heart of the explosion.
Like Akiko and Asami, Shigeyoshi Morimoto received a quick and intensive education in the physics of shock cocoons. Morimoto was one of Japan’s four champion kite-makers, which was why he and three others had been drafted and transported to Hiroshima, to design high-altitude observation kites for ship convoys. At a quarter past eight on the morning of August 6, Morimoto was not much farther from the bomb than Akiko Takakura. Like Akiko, he recalled no sound accompanying the flash. The multitiered, heavily tiled mansion shook and compressed around Mr. Morimoto and his two cousins; but the combination of tiles and three layers of thick wooden beams overhead attenuated the gamma bursts by a factor of at least ten. Rooms filled floor-to-ceiling with shelves of books further attenuated the rays and absorbed the compression waves. In a sense, the three cousins were being safeguarded by culture. The compression of the upper three floors occurred as if the building had been designed with lifesaving crumple zones of wood and paper in mind, cocooning the Morimoto family so gently that they survived in the center of Hiroshima with only a few minor bruises.
At twice the Morimoto and Akiko radius, nearly six city blocks north of the hypocenter, Private Shigeru Shimoyama had just stepped into a concrete-reinforced warehouse—where, as he would recall later for historians, he was "shaded from the flash, but not from the bang." The hand of a vengeful giant seemed to have flung him toward the back wall, while in this same instant the roof was pushed down and the floor was pulled up. The walls, too, were yanked inward, toward the center of the room, and the rear wall stopped the flying private like a catcher’s mitt. Outside, all of Shigeru’s fellow draftees died instantly. When he discovered that the reason he appeared to be suspended almost a meter above the floor was that his shoulders were nailed to a wooden crossbeam, and when a never-ending silence made him feel as if he were the only living man in Hiroshima, he began to suspect that everyone else might have gotten away with a better deal.
Just beyond the Shigeru radius, at the edge of the army burial grounds, the sisters of a local girls’ school were extracting oil from camphor trees when the sky ignited. The trees flew apart into thousands of flaming shreds. The granite tombstones nearby glowed cherry red, as if to herald the resurrection of the soldiers buried beneath, before the shockwave hurled them end over end off the top of Kyobashi Hill. Days later, Captain Mitsou Fuchida would arrive in the city center, searching for the nuns and their students. Finding the granite stones, and discovering that their outermost layers had boiled and turned to sand, he would understand that there was no point in looking for his friends. The stones would tell him everything he needed to know.
Excerpted from The Last Train from Hiroshima by Charles Pellegrino.
Copyright © 2010 by Charles Pellegrino.
Published in 2010 by Henry Holt and Company.
All rights reserved. This work is protected under copyright laws and reproduction is strictly prohibited. Permission to reproduce the material in any manner or medium must be secured from the Publisher.