Mankind

by Pamela D. Toler

  Aerial view of “Ground Zero” of the world’s first atomic bomb at the Los Alamos site July 16, 1945

  Scientists in primitive radiation suits prior to inspecting the “Ground Zero” site.

  An atomic blast at an unidentified location. The first successful test of an atomic bomb at Alamogordo, New Mexico, unleashed a force equal to 21 kilotons of TNT and left a bomb crater almost 2,400 feet across.

  In the most recent American campaigns, at Iwo Jima and Okinawa, the Japanese had inflicted horrendous casualties on U.S. forces in some of the most ferocious fighting of the war. Everyone expected that the Japanese would fight even more ferociously to defend their home islands. Military projections of American casualties for amphibious campaigns against Japan ranged from 193,500, including 43,500 dead, to 1,202,000, with 314,600 dead.

  Some scientists and government officials argued that a peaceful demonstration of the atomic bomb before its use on Japan would be enough to make Japan surrender. Others suggested that the Japanese should be given enough warning to allow them to evacuate the city before the bomb was dropped. General Groves and others argued that giving the Japanese advance warning of any kind would defeat the purpose of the bomb, which was to shock the Japanese into submission.

  Shortly after he was informed that the first bomb test was successful, President Truman ordered a combat drop on a Japanese city as soon as the army was ready.

  HIROSHIMA WAS THE SEVENTH- largest city in Japan and a major port for Japanese troops and supplies. Despite its importance to the imperial war effort, it was one of the few Japanese cities that had not been hit by American firebombs. Residents expected that to change. Tens of thousands had evacuated the city. The army had razed thousands of homes to create firebreaks, hoping to contain the fires caused by Gen. Curtis LeMay’s B-29s.

  Early on August 6, 1945, a single B-29 appeared over the city, triggering an air raid alert. Citizens took cover. Twenty minutes later, the plane disappeared and the air raid siren wailed again, signaling all clear.

  When three more B-29s came into view, residents of Hiroshima watched more in curiosity than fear. Such a small number of planes could not signal a major attack. When parachutes opened beneath two of the planes, a group of soldiers on the outskirts of the city cheered, assuming the planes had been hit and the crew was bailing out. Little did they know that the parachutes carried scientific instruments to measure the blast of the bomb the Enola Gay was about to drop.

  THE MISSION THAT CHANGED THE WAR

  AUGUST 6, 1945. BOMBER PILOT COL. PAUL TIBBETS, his copilot, Capt. Robert A. Lewis, and bombardier Maj. Thomas Ferebee sit in the pressurized cockpit of the B-29 Superfortress the Enola Gay. Their mission will change the world forever. Their destination? Hiroshima, Japan.

  The B-29 is a state-of-the-art weapon of war: a strategic bomber designed to fly higher and farther than any plane before it. The greatest technological advance of all rests in the bay behind the flight crew—a four-ton atomic bomb code-named “Little Boy,” powered by the most potent force on Earth. Little Boy carries a sphere of uranium the size of a grapefruit, enough to eliminate an entire city.

  The bomb commander for the mission, Capt. William Sterling Parsons, climbs through the tunnel into the bomb bay, followed by his assistant, Lt. Morris Jeppson. Parsons knows more about the bomb than anyone else. He helped Oppenheimer design the bomb. He was one of the scientists who constructed it. Now he must arm it for destruction.

  Col. Paul W. Tibbets (center) with the ground crew of the B-29 Enola Gay

  Parsons squats down in the cramped bay. Jeppson trains a flashlight over his commander’s shoulder, lighting the back end of the bomb. Parsons has practiced this procedure hundreds of times in preparation for this moment. He unscrews the breach plug and removes it. “Unscrewing breach.”

  The Enola Gay

  “Check.”

  Parsons picks up the powder charges. His hands and face begin to sweat. One wrong move and the mission will fail. “Inserting charges.” “Check.”

  Parsons reinserts the breach plug, screwing it back into place. The bomb is armed. The mission is now in the hands of Colonel Tibbets.

  As the Enola Gay nears Hiroshima, commanding officer Paul Tibbets is faced with a dangerous decision. The bomb’s target is only half a mile wide. Flying into the wind will make the bomb drop more accurate—but it will also slow the plane down, making it harder to escape the blast.

  Tibbets chooses the mission’s success over safety and heads the plane into the wind.

  He switches on a tone broadcast to warn the two escort planes that the bomb drop is about to occur. In sixty seconds the tone ends, and the bomb bay doors open automatically. The bomb drops out.

  Tibbets has just forty-five seconds to get away. He takes the plane into a steep dive, accelerating to escape the blast . . . and he and his crew escape.

  The people of Hiroshima will not be so lucky.

  Atomic explosion on Hiroshima, Japan, August 6, 1945

  Within forty-three seconds of the bomb’s release, high explosives inside the bomb fire a uranium bullet into a uranium target at the other end of the bomb at a speed of one thousand feet per second. Together, bullet and target trigger a nuclear chain reaction. In two seconds, the bomb detonates nineteen hundred feet above Hiroshima, generating an explosion equivalent to 16 kilotons of TNT. The temperature at the center of the explosion is ten thousand times hotter than the surface of the sun. A pressure wave of forty-six hundred pounds per square foot ripples out from the blast center, flattening buildings as far as 1.25 miles away.

  Hiroshima after the dropping of an atomic bomb, showing the devastation out about 0.4 miles

  Survivors of the explosion of the atom bomb at Hiroshima

  TENS OF THOUSANDS OF PEOPLE were killed in an instant. Everything directly beneath the bomb vaporized when it exploded, searing grim silhouettes of people who no longer existed into stone and pavement. Half a mile away from ground zero, people were reduced to small piles of smoking charcoal. Another tenth of a mile out, nine of every ten people who were outside when the bomb went off died.

  Many who survived the initial blast died in the fires that followed. Near the hypocenter, the extreme temperatures of the explosion caused anything that could burn to ignite. Farther away, the shock waves spread kitchen fires and knocked down utility poles, causing live wires to snap and spark. Built largely of wood and paper, the city became an inferno as thousands of individual fires grew and merged.

  Commercial Exhibition Hall, Hiroshima, Japan, 1945

  BUSHIDO

  The samurai class was officially disbanded in 1876, but the samurai code known as Bushido, the way of the warrior, played an important role in World War II.

  At its simplest, the code boils down to two basic tenets: loyalty and honor. Loyalty demanded that a warrior be willing to kill—or be killed—on behalf of his master. Death was preferable to the dishonor of surrender.

  In the “total war” culture of World War II, the tenets of Bushido shaped the actions of the Japanese people in ways that were incomprehensible to the West. From the Japanese perspective, prisoners of war had dishonored themselves by choosing surrender over death and deserved nothing but contempt. This attitude contributed to the brutal treatment of captives in Japanese camps. Kamikaze pilots crashed their explosive-laden planes directly into American ships, committing suicide at the order of their officers. Entire Japanese families, including children, threw themselves off cliffs or blew themselves up rather than suffer capture by American forces.

  Japanese Zero, 1939

  URANIUM

  Born in a stellar explosion six billion years ago and embedded in Earth’s crust, uranium lay dormant for millennia until scientists learned to split its atoms and unleash its apocalyptic power.

  The nucleus of every atom is made up of positively charged particles called protons, and particles without a charge, called neutrons. Because like charges repel each other, the protons create a force that at
tempts to push them apart. If the ratio of protons to neutrons is not too high, other forces within the atom hold the protons together. When there are too many protons, they are not held firmly together and the nucleus becomes unstable, or radioactive.

  Uranium is the heaviest naturally occurring element. With 92 protons in its nucleus, the uranium atom can barely hold itself together, making it the easiest atom to split. Once split, it sets off a chain reaction that can shatter a trillion trillion atoms in one second. The energy released by a kilogram of uranium through nuclear fission is about 2.5 million times the amount of energy released by burning one kilogram of coal.

  Luckily, uranium isn’t as common as coal—and it isn’t dangerous until it has been processed down to one single form: U-235, which makes up about 0.7 percent of naturally occurring uranium.

  Uranium is not found in a concentrated form. Many tons of ore have to be processed to obtain even one gram of the element. Once processed, uranium has to be further refined before it can be used to create a bomb.

  Uranium occurs in three different forms: U-234, U-235, and U-238. Typically all three are mixed together in the ore from which uranium is extracted. Only when the ore has been processed to the point where it has a concentration of 20 percent of U-235 is it capable of generating a dangerous chain reaction.

  “We are carrying the world’s first atomic bomb. When the bomb is dropped, Lieutenant Beser will record our reactions to what we see. This recording is being made for history. Watch your language and don’t clutter up the intercom.”

  —Colonel Paul Tibbets’s instructions to the crew of the Enola Gay shortly after takeoff

  HOW “LITTLE BOY” WORKED

  The development of the nuclear bomb began with the discovery by German scientists Otto Hahn and Fritz Strass-man that bombarding the radioactive element uranium with neutrons split the nuclei of uranium atoms in two, creating two new elements. These elements, called barium and krypton, added up to less mass than the original uranium, raising the question, what happened to the rest of the mass?

  Additional experiments proved that the missing mass was transformed into energy. The two fragments of a split element repel each other with one hundred million times more force than is released in a comparable chemical reaction. In addition, each fissioned atom releases several neutrons that can cause more atoms to fission, producing a chain reaction. Spontaneous fissions may occur in a small amount of purified U-235, but after a few fissions the process will stop. With a large enough piece of U-235—called a critical mass—the number of new fissions increases exponentially until the accumulated force blows the uranium apart and stops the reaction.

  Little Boy’s steel housing contained a tube with subcritical pieces of U-235 at either end. One piece looked like a rounded bullet; the other consisted of rings. High explosives fired the bullet at high speed down the tube and into the rings. Together, the U-235 reached critical mass, causing a chain reaction and, within a fraction of a second, producing the massive explosion that destroyed Hiroshima.

  Replica of Little Boy, ca. 1945

  HIROSHIMA TODAY

  In the years following the bombing of Hiroshima, instead of simply rebuilding the city, the survivors turned the city into an exhibit for peace. The Hiroshima Peace Memorial Park and its Peace Memorial Museum, built on the open field created by the bomb, were designed not only as memorials to those who died but as monuments to peace itself.

  The Peace Memorial Museum receives more than a million visitors each year, but physical monuments and museums are only a small part of Hiroshima’s efforts to promote peace. Peace education is taught in every school. The city hosts summer programs for children and seminars and conferences for adults. And the mayor issues a formal protest every time a country tests a nuclear weapon.

  Each year, on August 6, at 8:15 a.m., tens of thousands gather at Hiroshima Peace Memorial Park to make a declaration for peace. At dusk, they gather on the banks of the Motoyasu River, with paper lanterns bearing the names of the dead. Attendees light the candles inside the lanterns, then send the lanterns floating downriver to the Inland Sea.

  The devastation caused by the explosion itself was only the beginning of the horror. The bomb dropped on Hiroshima continued to kill long after the war was over. The fireball had released radiation waves that spread far beyond the range predicted by Manhattan Project scientists, poisoning those who survived the blast. The radioactive fallout, known as the “ashes of death,” destroyed its victims’ ability to create new blood cells. In the decade after the war, thousands died each year from the long-term effects of radiation poisoning.

  “Let all the souls here rest in peace; for we shall not repeat the evil.”—Inscription on the Memorial Cenotaph, a monument for the atomic bomb victims, Hiroshima

  With the atomic bomb, we crossed a new threshold, creating a device more lethal than the plague and more destructive than TNT. The development of atomic bombs with the power to end the human species and destroy the planet has had profound implications for mankind, sparking intense fear and debate about the ethics of their use.

  Floating lanterns on the Motoyasugawa River during the Peace Memorial Ceremony in Hiroshima, Japan, and the Atomic Bomb Dome, an exhibition hall built in 1915 and one of the few buildings to survive the blast.

  The population of Dawson Creek, British Columbia, where the Alaska Highway began, tripled overnight with the arrival of one regiment of army engineers.

  BORN IN A REMOTE CORNER OF Africa, humans have spent millennia battling Earth’s geography. Two of our most basic instincts—the drive to explore and the need to communicate—have led us to build roads across the most inhospitable places on Earth: the silk roads across Central Asia, the invisible routes of the Saharan salt trade, the high mountain roads of Incan Peru. Thousands of miles of road linked the imperial centers of Persia, China, India and Rome to their frontiers.

  The Alaskan Highway, like many earlier roads, demonstrates mankind’s ability to overcome obstacles with an engineering marvel. The highway was created in the wake of Pearl Harbor. Americans feared that the Japanese would continue across the Pacific and attack the West Coast. Alaska, not yet a state and isolated from the American mainland, seemed particularly vulnerable to Japanese attack. The Aleutian Islands were only 750 miles from the nearest Japanese military base. Alaska’s military resources were scant: only twenty thousand troops stationed across the enormous territory, twelve bombers, and twenty fighter planes. The officer in charge of the Alaska Defense Command made the point sharply in a telegram to Washington: “If the Japanese come here, I can’t defend Alaska. I don’t have the resources.”

  American strategists had considered the possibility of a road through Canada to Alaska on and off since 1865, but no one had taken the necessary action. With the memory of Pearl Harbor fresh in everyone’s minds, President Roosevelt pushed the project through.

  The task fell to Gen. William M. Hoge, expert engineer and decorated war hero. His orders were deceptively simple. Build fourteen hundred miles of highway from Dawson Creek, British Columbia, to Delta Junction in Alaska.

  Historically, roads are built over existing paths. The Alaskan Highway was created where no natural road had evolved, cut across a heavily wooded, often swampy wilderness. Because of the difficult terrain, the plan was that the army would build a rough road through the wilderness in 1942 to open the way for trucks. Civilian contractors would come behind them the following year to create a permanent highway.

  In late spring of 1942, the army dispatched 10,670 American troops to Alaska to build an engineering marvel: a road carved out of the wilderness to provide a military supply line to bring troops, food, and supplies to strategic points in the Alaskan high-country. Men pulled from all walks of life were put behind the wheels of bulldozers and supply trucks with little or no training and told to clear their way through a frozen wasteland.

  The Alaskan Highway was created where no natural road had evolved. . . . Their biggest obstacle was t
ime.

  Their biggest obstacle was time. The work crews needed to complete the highway in eight months, before the deadly Alaskan winter made construction impossible. Construction began simultaneously in three locations, with crews building separate sections of the road hundreds of miles apart. Seven regiments worked on the highway, three of them African-American. At first the African-American regiments were given menial jobs supporting the white regiments. It soon became clear that if the road were going to be finished on time, every soldier would have to work on construction. For the first time, black and white regiments performed identical tasks, though not with identical equipment. Black regiments were provided with fewer bulldozers and more wheelbarrows and shovels than their white counterparts.

  A pile driver pounding bridge supports into the riverbed, completing another link in the Alaskan highway, 1942.

  The Army Corps of Engineers knew how to build infrastructure quickly under wartime conditions, but they didn’t know how to build in Alaska’s subarctic environment. Transportation to all three construction locations was difficult. Supplies, workers, and machinery were often stuck in transit—some of them for the duration of the project. The army often parachuted emergency supplies to their troops. Equipment breakdowns occurred hourly. Engineers waded chest-deep in freezing lakes to build bridge trestles. They battled with mosquitoes, mud, and the moss-laden arctic bog land known as muskeg. Frostbite was a permanent enemy.