The Trinity Test, the day the Nuclear Age began, 1945

Until the atomic bomb is tested, its effectiveness will remain in doubt. The world had never seen a nuclear explosion before, and estimates vary widely on how much energy would be released. Some Los Alamos scientists continue to doubt privately that it would work at all.

Only enough weapons-grade uranium was available for a single bomb, and confidence in the gun-type design was high, so on July 14, 1945, most uranium bombs ("Little Boy") made their journey west across the Pacific. started. Its design has been thoroughly tested.

A test of the plutonium bomb seemed important, however, both to confirm its novel detonation design and to collect data on nuclear explosions in general.

Several plutonium bombs were now "in the pipeline" and would be available over the next few weeks and months. So it was decided to test one of these.

Robert Oppenheimer named it the "Trinity" trial, a name inspired by the poems of John Donne. The site chosen was a remote corner on the Alamgordo bombing range known as "Jornada del Muerto" or "Journey of Death", 210 miles south of Los Alamos.

Elaborate equipment testing was carried out around the site with the detonation of large quantities of conventional explosives on 7 May. Preparations continued in May and June and were completed by early July.

Three observation bunkers located 5.6 miles north, west and south of the firing tower at ground zero will attempt to measure key aspects of the response. Specifically, scientists will attempt to determine the symmetry of the implant and the amount of energy released.

Additional measurements will be made to determine damage estimates, and equipment will record the behavior of the fireball. The biggest concern was the control of the radioactivity that the test equipment would release.

Not completely satisfied to rely on favorable meteorological conditions to carry radioactivity into the upper atmosphere, the military prepared to evacuate people in the surrounding areas.

On July 12, the plutonium corps was moved to the test area in an Army sedan. The non-nuclear components left for the test site at 12:01 pm on Friday the 13th.

During the day on the 13th, the final assembly of the "Gadget" (as it was nicknamed) took place at McDonald's Ranch House. By 5:00 p.m. on the 15th, the equipment was assembled and hoisted atop the 100-foot firing tower.

Leslie Groves, Vannevar Bush, James Conant, Ernest Lawrence, Thomas Farrell, James Chadwick, and others rushed to the test area, where it was raining.

Standing at the S-10,000 control bunker, Groves and Oppenheimer discussed what to do if the weather didn't break in time for the scheduled 4:00 AM test.

To break the tension, Fermi began by offering anyone listening to the stakes "whether or not the bomb would ignite the atmosphere, and if so, whether it would only destroy New Mexico or destroy the world." will give". Oppenheimer himself made a ten dollar bet against George Kistiakowski's full month's salary that the bomb would not work at all.

Meanwhile, Edward Taylor was troubling everyone by applying a generous amount of sunscreen in the dark before dawn and offering to pass it on.

At 3:30, Groves and Oppenheimer pushed the time back to 5:30. At four o'clock the rain stopped. Kistiakowski and his team armed the device shortly after 5:00 and retreated to S-10,000. As his policy sees each accident from different locations, Groves leaves Oppenheimer and joins Bush and Conant at base camp.

Those in the shelters heard the countdown over the public address system, while base camp supervisors picked it up on an FM radio signal.

During the final seconds, most observers lay on the ground with their feet facing the Trinity site and just waited. As the countdown neared a minute, Isidore Rabi said to the man lying next to him, Kenneth Grissen, "Aren't you nervous?" "No" was Grissen's answer.

As Groves later wrote, "As I lay there at the last second, all I thought about was what I would do if the countdown went to zero and nothing happened".

Conant said he never knew seconds could be so long. As the countdown reached 10 seconds, Grissen suddenly said to his neighbor Rabi, "I'm scared now". Three, two, one, and Sam Allison shouted, "Now!"

The atomic age began at exactly 5:30 on Monday, July 16, 1945. While members of the Manhattan Project staff watched anxiously, equipment exploded in the New Mexico desert, vaporizing the tower and turning the asphalt into green sand around the base of the tower. A few seconds after the explosion, a huge explosion wave came and heat spread throughout the desert.

No one could see the radiation produced by the explosion, but they all knew it was there. The steel container "Jumbo", which weighed more than 200 tons and was taken into the desert only to be finished testing, was rejected despite standing at half a mile from ground zero.

As the orange and yellow fireball spread and spread, a second pillar, narrower than the first, flattened into the shape of a rose and a mushroom, thus providing the Atomic Age with a visual image that stood as a symbol of power. As imprinted on human consciousness. and terrible destruction.

The most common immediate reactions to the explosion were surprise, joy, and relief. Lawrence was stepping out of his car when, in his words, everything went "from dark to bright sunshine in an instant"; He was "stunned by a moment's surprise".

One soldier was heard saying, "The long hair has let it get away from them!" Hans Bethe, looking directly at the explosion, was completely blind for about half a minute. Norris Bradbury pointed out that "the atomic bomb did not fit any preconceived notions that anyone had".

The blast wave knocked Kistyakovsky (who was more than five miles away) to the ground. He quickly kicked his feet and slapped Oppenheimer on the back, saying, "Oppie, you owe ten dollars". Physicist Viktor Weisskopf reported that "our first feeling was that of euphoria".

Isidore Rabi used the word "jubilant". Within minutes Rabi was passing by a bottle of whiskey. Bush, Conant and Groves shake hands at Base Camp.

When they met, Groves told Oppenheimer, "I am proud of you". Groves' assistant, Thomas Farrell, commented to his boss that "the war is over", to which Groves replied, "Yes, after two bombs were dropped on Japan".

Perhaps the most mundane response of all was Fermi's: he had calculated ahead of time how far the blast wave could displace the tiny pieces of paper left in it.

About 40 seconds after the explosion, Fermi stood up, sprayed his pre-prepared slips of paper into the nuclear air, and estimated from his deflection that the test had released the energy equivalent to 10,000 tons of TNT.

The actual result as eventually calculated – 21,000 tonnes (21 kilotons) – was more than twice Fermi's estimate with this experiment and four times more than had been predicted by most at Los Alamos.

Soon the shock and excitement gave way to more sober reflections. Rabi told that after the initial enthusiasm, soon the people present there felt cold.

The trial director, Kenneth Bainbridge, called the explosion a "dishonest and horrific performance" and remarked to Oppenheimer, "We are all sons of bitches now". Expressions of horror and remorse are particularly common in the later writings of those who were present.

Oppenheimer wrote that the experience called into his mind the legend of Prometheus, punished by Zeus for giving fire to man, and also said that he thought of Alfred Nobel's vain hope that dynamite would end the wars. .

Most famously, Oppenheimer later recalled that the explosion reminded him of a line from the Hindu sacred text, the Bhagavad-Gita: "Now I have become death, the destroyer of the world".

The terrifying destructive power of nuclear weapons and the uses to which they could be used were to haunt many Manhattan Project scientists for the rest of their lives.

The success of the Trinity test meant that both types of bombs – the uranium design, untested but considered reliable, and the plutonium design, which had just been successfully tested – were now available for use in the war against Japan. .

Little Boy, the uranium bomb, was first dropped on Hiroshima on 6 August, while the plutonium weapon, Fat Man, was dropped on Nagasaki three days later on 9 August. Within days, Japan offered to surrender.