Friday, 3 December 2021

WHEN PHYSICS HELPED THE US WIN THE WAR: HISTORY OF THE ATOMIC BOMB

 

 


We all know what happened on August 6, 1945: the first atomic bomb was dropped on Hiroshima, destroying an entire city and killing thousands and thousands of people.

What could exist only in fantasy books became true: mankind touched its lowest bottom.

 However, what many people don’t know is that the atomic bomb was brought about by a glorious and revolutionary discovery in science.

Up to that moment it was common belief that an atom couldn’t be split. But in the late 1930s two German scientists, Otto Hahn and Fritz Strassmann, started to experiment with radioactivity and nuclear fission of atoms of uranium: they bombarded uranium with neutrons achieving surprising results which were in contrast with what had always been believed up to then.

And then, in 1939, the revolution happened: they discovered that when an atom splits, it generates a powerful burst of explosive energy.

But the excitement of the discovery soon became fear of nuclear weapons.

For this reason an Hungarian scientist emigrated to the US, persuaded Einstein to write a letter to the US president Roosevelt to alert him about the dangers of the nuclear weapons. The American president  seemed to be reluctant  at the beginning, but then he was convinced by one of his men and established the Advisory Committee on Uranium.

 

Not too late after that, in 1942 the “Manhattan project” was approved. It was a US project made by a group of scientists, aiming to the development of weapons and especially atomic bombs. It was  created to face Germany, which was thought to have been developing atomic weapons since the early 30s. In fact, the German intelligence had discovered the direction of nuclear research in the United States  and had started to carry on their own research.

 

But the main target of America was Japan.

In July 1945,  the  newly elected president, Harry Truman, called for Japan’s surrender, warning the country that they would face utter destruction. Indeed, 350 Japanese airplanes had bombed Pearl Harbor in 1941, forcing the US to enter the war.

And then in July 16, 1945, in New Mexico, the group of the Manhattan project launched the first successful atomic bob, called with the code name “Trinity Test”. The cloud of the radioactive vapor caused by the explosion was 9km high and the bright light of the detonation exploded with such intensity that the flash was perceived at a distance of 220km.

Here’s what Robert Oppenheimer, an American physicist, declared right after the explosion: ”Now I am become Death, the destroyer of worlds”, referring to the bomb and to himself, one of its makers.

The director of the test too  seemed to have caught the potential danger of what he had before his eyes.

 

On July 24, President Truman informed Stalin that the US had “an unprecedented new weapon with destructive power”’. His men had advised him that it was necessary to inform URSS about the success of the Manhattan project.  President Truman was surprised that Stalin didn’t show any particular interest for the news of the bomb: as a matter of fact, all that he said was that he hoped for  “a good use against Japan” .

Years later they would find out that his silence was related to the fact that URSS had been developing their own nuclear program.

 

On July 25, an order was written that authorized the use of the atomic bomb against Japan, signed by president Truman. The order didn’t say anything about military goals or saving civilians. Three cities were chosen as their targets:  Hiroshima, Kyoto and Niigata, but this last one was replaced with Nagasaki because of its cultural significance.

It was a war declaration agains Japan: US, URSS and Great Britain approved the plan.

But the prime minister  Suzuki openly announced that Japan would ignore the ultimatum.

 

On August 6, at 8.15am a bomb called Little Boy was dropped on Hiroshima  by  Enola Gay.

70 Thousands of people were killed and many others injured in an instant. It exploded at a temperature of one million degrees centigrade, creating a giant hot fireball.

Seeing the huge cloud after the explosion, co-pilot Robert Lewis scribbled on his notebook: ”oh my God, what have we done?”.

Pilot Paul Tibbes, who had named the plane after his mum, looked back and saw “a giant purple mushroom boiling upward”. Then over the income he announced to his crew: ”Fellows, you have just dropped the first atomic bomb in history”.

Futaba Kitayama, an eye witness who ran for her life, would then tell: ”I looked up and saw an airplane as silver as treasure flying from east to west coast in the cloudless blue sky. Then someone next to me screamed “A parachute is falling!”. Few seconds later that parachute exploded into an indescribable light”.

She also recalled that there were “bodies floating like dead dogs” and thought: ”Could such terracing sights be of this world?”.

 

3 days later, another bomb called FatMan would be dropped on Nagasaki. The bomb was dropped at 11.02am but, luckily, the hills surrounding the city did a good job in containing the destructive force of the bomb. However,  the number of people killed is estimated between 60,000 and 80,000.

As it was not enough, the responsible for the Manhattan project, was ready for another bomb to use against Japan on August 17 or 18.

But , luckily, it didn’t happen: Japan surrendered on August 14.

 

 After the dropping of the bombs, the plane’s pilot Tibbets repeatedly steadily that he felt no personal guilt for doing what he said was “his military duty”. However he would then doubt his statement.

Co-pilot Lewis instead raised money for medical treatment for the Hiroshima maidens, young girls who have been disfigured or crippled by the explosion.

 

A special mention must be reserved to Einstein , who openly regretted the role he had had in the development of the atomic bomb. He said: ”Had I known that the Germans would not succeed in producing an atomic bomb…I would have never lifted a finger”.

Maria, 4scB

  

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