Zero hour for the test was 4 a.m. on 16 July, but at 2 a.m. violent thunderstorms erupted unexpectedly. Winds of thirty miles per hour scoured the desert, while heavy rain battered the shelters and the Trinity base camp. The scientists even feared that the bomb might "be set off accidentally," as Isidor Rabi later recalled. Hearing "an unbelievable noise," Emilio Segre went to investigate but found it was only the sound of "hundreds of frogs in the act of making love in a big hole that had filled with water." The presence of a highly agitated Groves added to the pressure on the three men—all by then exhausted—who had the power to cancel the test: Robert Oppenheimer, Kenneth Bainbridge, a Harvard experimental physicist appointed test director in March 1944, and Jack Hubbard. They debated what to do. Hubbard advised that the test could not go ahead at 4 a.m. Yet, somewhat to Groves's surprise, after careful scrutiny of the data he predicted that by dawn conditions would be acceptable. The men set a new time of 5:30 a.m.
At 4:15 a.m. Hubbard's final weather forecast confirmed that the test could indeed proceed. Shortly after 5 a.m. Bainbridge ordered the bomb's timing device to be activated. Meanwhile Groves, fearful of the possible effects on the local community, alerted the governor of New Mexico that he might have to declare a state of emergency and evacuate people from the neighborhood. He gave no details as to why.
At c: 29 a.m. a rocket streaked across the sky to signal that there was only a minute to go before detonation. At their observation point on Compaiiia Hill, twenty miles northwest of ground zero, Hans Bethe and Edward Teller applied suntan lotion to protect themselves from the coming flash. Bethe had calculated that the Trinity bomb could not ignite the Earth's atmosphere. Fear that the explosion might trigger an unstoppable, catastrophic sequence that turned the Earth into a burning star had long troubled the Los Alamos team. Their concern was that this might result not from fission but from fusion. If a nuclear explosion produced by atomic fission of heavy elements, such as uranium or plutonium, generated sufficient heat and pressure, it might in turn fuse the light atoms of hydrogen, helium, and nitrogen in the atmosphere and cause them to ignite—the process that causes the sun and stars to burn. In the early days of the project, Oppenheimer had been so worried by some figures produced by Teller that he had consulted Arthur Compton, who told him that if the risk exceeded three in a million the bomb project must halt. Teller had subsequently reworked his figures, showing the risk to be much less than he originally supposed and justifying the project's continuation. He had also confirmed Bethe's more recent calculations. Nevertheless, both Teller and Bethe spent a long, fraught sixty seconds.
It happened as planned. James Chadwick, also on Compania Hill, remembered, "The first grey light of dawn was appearing as we lay or sat on the ground. Except for the faint twitterings of a few early birds there was complete silence. Then a great blinding light lit up the sky and earth as if God himself appeared among us. . . . [then the] explosion, sudden and sharp as if the skies had cracked." Beside him Otto Frisch, afraid of being dazzled, had turned his back. He was watching the landscape take substance in the pale dawn when "suddenly and without any sound, the hills were bathed in brilliant light, as if somebody had turned the sun on with a swatch." He turned to the source of the light, but it was still too bright to focus on. Stealing a fewr brief, tantalizing glances, he gained "the impression of a small very brilliant core, much smaller in appearance than the sun, surrounded by decreasing and reddening brightness with no definite boundary."
Trinity test bomb
After a few seconds he was able to look at it properly and saw "a pretty perfect red ball, about as big as the sun, and connected to the ground by a short, grey stem. The ball rose slowly, lengthening its stem. . . . A structure of darker and lighter irregularities became visible, making the ball look somewhat like a raspberry. Then its motion slowed down and it flattened out, but still remained connected to the ground by its stem, looking more than ever like the trunk of an elephant. Then a hump grew out of its top surface and a second mushroom grew out of the top of the first one." The whole was surrounded by "a purplish blue glow." Frisch waited, fingers in ears, for the expected blast. The noise, when it reached the man who six years earlier, with his aunt Lise Meitner, had proved the reality of nuclear fission, was in his view "quite respectable." A long rumbling followed, "not quite like thunder but more regular, like huge noisy wagons running around in the hills."*
To Rudolf Peierls, the explosion had a symbolic as well as a scientific significance: "To us that trial explosion had been the climax. . . . The brilliant and blinding flash . . . told us . . . we had done our job. In that instant. . . still awed by the indescribable spectacle . . . we thought more about the work successfully completed than about the consequences."
Robert Oppenheimer's first reaction was also a surge of relief, though, as he later told reporters, he was "a little scared of what we had made." A line from his beloved Bhagavad Gita raced through his brain: "I am become Death, the shatterer of worlds." To others, though, Oppenheimer's mood seemed close to euphoria. Rabi recalled, Oppenheimer's "walk was like [the film] High Noon, I think it's the best I could describe it—this kind of strut." General Groves's reaction was unequivocal satisfaction. During the final seconds he had thought "only of what I would do if, when the countdown got to zero, nothing happened."
The important question was: How big had the blast been? Enrico Fermi, who to Groves's irritation had the night before been taking bets on the chances of the explosion igniting the atmosphere, conducted a simple but ingenious experiment. Just after the flash, Groves saw him "dribbling" some torn fragments of paper "from his hand toward the ground. There was no ground wind, so that when the shock wave hit it knocked some of the scraps several feet away." Fermi measured precisely how far the blast wave had carried them; then, using his slide rule, he calculated the force of the explosion. It was equivalent, he reckoned, to some ten thousand tons of TNT. His improvised "paper chase," given how much was unknown, was surprisingly accurate; the blast had, in fact, been equivalent to twenty thousand tons of TNT.
Only a few hours after the Trinity test of the plutonium bomb, the heavy cruiser the USS Indianapolis left San Francisco. On board were a gun assembly in a fifteen-foot crate and a lead bucket containing a uranium core—the key components for Little Boy, the uranium-fueled bomb, which the scientists had decided need not be tested before its use in the field.
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The message announcing the success of Trinity reached Stimson at Potsdam in the following terms: "Operated on this morning. Diagnosis not yet complete but results seem satisfactory and already exceed expectations." Stimson informed Truman and Byrnes. That night Truman wrote in his diary, "I hope for some sort of peace, but I fear that machines are ahead of mortals by some centuries, and when mortals catch up perhaps there'll be no reason for any of it."
The next day Stimson passed Churchill a cryptic note, "Babies are satisfactorily born," which Churchill failed to understand. Stimson then told him explicitly. His diary records Churchill's subsequent reaction: " 'Now I know what happened to Truman yesterday. I couldn't understand it. When he got to the meeting after having read this report he was a changed man. He told the Russians just where they got on and off and generally bossed the whole meeting.' Churchill said he now understood how this pepping up had taken place and that he felt the same way." According to his own top general, Lord Alanbrooke, Churchill was "completely carried away. It was now no longer necessary for the Russians to come into the Japanese war; the new explosive alone was sufficient to settle the matter. Furthermore we now had something in our hands which would redress the balance with the Russians. The secret of this explosive and the power to use it would completely alter the diplomatic equilibrium which was adrift since the defeat of Germany. Now we had a new value [said Churchill], pushing his chin out and scowling, now we could say if you insist on doing this or that well we can just blot out Moscow, then Stalingrad, then Kiev, Karkhov, Sebastopol etc., etc. Then where are the Russ
ians?" A note from Churchill to his foreign secretary, Anthony Eden, confirmed that his elation and his disdain for Russia were shared by his American counterpart: "It is quite clear that the United States do not at the present time desire Russian participation in the war against Japan."
With Churchill's agreement, Truman told Stalin of the bomb. At the end of one day's meetings he wandered over to Stalin. He later described their conversation: "I casually mentioned to Stalin that we had a new wreapon of unusual destructive force. The Russian premier showed no special interest. All he said was that he was glad to hear it and hoped we would make 'good use of it against the Japanese.' "Their mutual nonchalance concealed not only Truman's understanding of the bomb's potential but also Stalin's prior knowledge of the bomb from Klaus Fuchs's detailed reports. Stalin was already pressing his generals to hasten their plans for Soviet entry into the war. Nikita Khrushchev later wrote, "Stalin had his doubts about whether the Americans would keep their word. . . . What if Japan capitulated before we entered the war? The Americans might say, 'we don't owe you anything.'"
The Soviets had, immediately prior to the conference, received renewed peace feelers from the Japanese, to which they had given a noncommittal reply. Fortified by their knowledge of the Trinity test, aware of the Japanese peace approaches, and without consulting Stalin, on 26 July Truman, Churchill, and the Chinese leader Chiang Kai-shek issued the Potsdam Declaration, offering to Japan what they called "an opportunity to end this war" on the basis of "unconditional surrender." The declaration ended: "The alternative for Japan is prompt and utter destruction."
Two days earlier, General Marshall and Henry Stimson had approved a directive drafted by General Groves authorizing the atomic bombing of Japan. Although they must have consulted President Truman, his formal consent does not appear in the surviving documents. The first part of the directive to General Carl Spaatz, the newly appointed commander of the Strategic Air Force, reads:
1. The SO9 Composite Group, 20th Air Force will deliver itsfrst special bomb as soon as weather will permit visual bombing after about 3 August 1945 on one of the targets: Hiroshima, Kokura, Niigata and Nagasaki....
2. Additional bombs will be delivered on the above targets as soon as made ready by the project staff.
On 26 July, at the end of her ten-day voyage from San Franscico, the USS Indianapolis reached Tinian. Two days later, the Japanese prime minister rejected the Potsdam offer. His government would "ignore it [and] press forward resolutely for the successful conclusion of the war." The Tokyo newspaper Mainnichi dismissed the Potsdam Declaration as "a laughable matter."
*In his autobiography Teller reflected that the scientists should have done more to understand what would have been involved technically in a demonstration to the Japanese and then to have informed the politicians.
*The emblematic mushroom effect resulted from the thermal updraft created by the explosion and the heat it produced, which sent debris up into the sky, where it flattened out as it reached the stratosphere and the energy dissipated.
TWENTY-THREE
"AN ELONGATED TRASH CAN
WITH FINS"
TINIAN IS A SMALL ISLAND about twelve miles long and only five miles wide at its broadest. Fringed by pale sand and coral reefs, Tinian was the center of the American strategic bombing offensive against Japan, which lay some thirteen hundred miles directly to the north. The four parallel runways of North Field, one of the two airfields on the island, were, at 8,500 feet, said to be the longest in the world at the time and could launch four B-29S simultaneously at forty-five-second intervals, or more than three hundred planes per hour. Many of the streets on the base were named after those in Manhattan, such as Park Avenue and Riverside Drive. The area reserved for Paul Tibbets's £09th Composite Group was known as "the Columbia University District."
Their compound was surrounded by a high fence topped with barbed wire with an inner compound of windowless huts surrounded by more barbed wire and guards. Here a thirty-seven-man-strong technical team, including Luis Alvarez and William Penney and under the command of Deak Parsons, worked on the assembly of the two bombs. Conditions in general on Tinian were fairly primitive, and the 509th officers' club was made of plywood from recycled packing crates, canvas, and mosquito netting. Many of the officers and men lived in tents. One of their occupants wrote: "The bathroom is a pipe in the open connected to a waterpipe; the tank itself is made out of salvaged bomb containers; there is no hot water. Beside the coral path leading to the bathroom is a derelict Japanese foxhole. Beyond it by the sea is the graveyard of 1,100 marines who died in the battle for the island." Despite such discomforts, the 509th had the highest priority rating on the island and the best of everything going. Their priority status provoked jealousy among the base's other personnel, who were entirely ignorant of the mission of their pampered neighbors. Some disgruntled spirits threw stones over the wire onto the corrugated iron roofs of the group's accommodation huts to keep the occupants awake at night.
The barracks on Tinian Island
Each night also, U.S. marines went out to hunt the small numbers of Japanese soldiers still holding out in the luxuriant jungle or in caves in the one-hundred-foot-high cliffs overlooking the air base and its surrounding sugarcane fields. One of them, Chief Warrant Officer Kizo Imai, later claimed to have noticed the special compound set up for the 509th and pondered how best to get out a message for it to be attacked. Paul Tibbets recalled that the Japanese propagandist Tokyo Rose mentioned the distinctive arrow marking on the tails of the 509th's bombers in one of her radio broadcasts. Perhaps an unknown Japanese soldier did get a message through.
The crews of the £09th spent July 1945 in training, including flying daylight missions of two or three bombers over Japan, during which they dropped orange pumpkin-shaped practice bombs containing only sufficient powder to show where detonation occurred. These practice sessions confirmed to Tibbets the crews' competence and the inability of Japanese antiaircraft fire to reach thirty thousand feet. Fighters were only rarely seen, and Tibbets hoped that the insignificant effects of the practice bombs might lull the Japanese into a false sense of security about lone high-flying bombers. Tibbets himself went on none of these flights, forbidden to fly over enemy territory in case he was shot down and captured. Instead he worked out with senior officers the operational plans for the final bombing mission. Because August was often cloudy over Japan and the mission needed clear weather, his bomb-carrying plane would be preceded by three weather aircraft: one to check the weather over the primary target, and the others over each of the alternates. The bombing plane would be accompanied by a plane carrying scientists and scientific instruments and another to take photographs. A spare aircraft would fly as far as Iwo Jima, halfway along the six-hour route to Japan. In the event of any mechanical problems aboard the lead plane, it would land at Iwo Jima and the bomb would be transferred to the spare plane, which would complete the mission.
The Indianapolis had anchored one thousand yards offshore because there was no quay deep enough for her to berth alongside. Her secret cargo was transferred to a tank landing craft, brought ashore, and carried to the windowless huts. The Indianapolis then sailed unescorted for Guam. C-54 Green Hornet transport aircraft delivered some final components for the uranium bomb, Little Boy, on 28 July, and the bomb's assembly was virtually complete by 31 July. Little Boy was 120 inches long, 28 inches in diameter, and weighed about 9,700 pounds. To one observer it looked like "an elongated trash can with fins."
The final components—the bomb casings—for the plutonium implosion bomb, Fat Man, the same type tested in the Jornada del Muerto, did not arrive until midday on 2 August. Among the other cargo in one of the B-29S transporting them was a ten-foot-high statue of Christ being taken to Tinian at the request of one of the chaplains. The components of Fat Man were hurried to the secure inner area, where Luis Alvarez began quickly to assemble them.
One of Britain's most experienced bomber pilots, Captain Leonard Ches
hire, holder of Britain's highest decoration, the Victoria Cross, and a former leader of the famous 61 7 "Dam Busters" squadron, was on Tinian expecting to be an observer on the first atomic bomb mission. He shared a tent with William Penney, who also expected to fly on the mission as a British scientific observer. In early August Cheshire dropped in on the assembly of Fat Man. He recalled howr Luis Alvarez "straightened up and without much formality began explaining the basic functions of the gadgetry . . . little of wdiich I grasped despite his obvious efforts to keep it simple. Then . . . he walked across to a yellow box lying on the floor and casually kicked it open with his foot. Inside I saw what appeared to be a metallic sphere about the size of a football. . . . it did not strike me as anything very special." Then Alvarez told him it wras the plutonium core of the bomb.
"I must have looked startled, for he told me not to worry; it was perfectly harmless and I was quite free to touch it if I wanted, provided I wore a pair of gloves. . . . Disbelief that the new5 monster bomb could be lying haphazardly on the floor . . . was followed by a sense of awe. Then I pulled myself together, accepted the gloves that Alvarez offered me and touched it. The sensation was rather like that of the first time you touch a live snake: you recoil from what you know will feel slimy and repulsive, and then to your surprise find that it is warmish, almost friendly. . . . Hitherto the bomb had conjured images of devastating, unimaginable power. . . . True, there was a potentially lethal side to it: but equally an inert side that left it totally subservient to man's will."
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Just after midnight on the morning of 30 July, the cruiser Indianapolis was torpedoed en route to Guam by a Japanese submarine and sank before being able to send a distress call. However, U.S. signals intelligence routinely intercepted and decoded a message from the Japanese submarine reporting the sinking of a "battleship of Idaho class." Intelligence passed the decode to naval headquarters on Guam on the morning of 30 July, but no action was taken because no battleships were known to be in the region. It was not until 2 August that a plane on a routine patrol spotted survivors from the air. Only 318 sailors out of the crew of 1,169 were still alive to be rescued; of those who survived the initial attack, 484 had died in the water of their wounds or of exposure or had been eaten by sharks. It was the greatest loss at sea in the history of the U.S. Navy and the last major warship to go down in World War II. When news of the Indianapolis's sinking reached Tinian, it darkened men's moods, particularly Jacob Beser, who, before the cruiser left, had enjoyed a convivial reunion with an old schoolfriend serving aboard her who was now among the dead.
Before the Fallout Page 36