Dawn of Nuclear Age: Manhattan Project

Throughout human history, there have been many moments that changed us, redefined how we do things, and tipped the balance of history. Today, I will look at one of those moments that pushed us into the modern nuclear age. Next week, I will put up part 2 of this blog entry where I talk about the day itself that changed history when Japan was nuked in 1945.

In the early 1940s, physicists, engineers, and others were secretly gathered together by members of the US government about a project they were to work on. No details were disclosed, and to force secrecy, different teams were spread out across the country working on their own part with no knowledge of other teams. Only a few people, including top level officials, from the US side knew what was being worked on. The British suspected it, but they were not informed by FDR or Senate or anyone (Soviets were not told at all). Their overall end goal was to build a nuclear fission bomb.

oppenheimer

Introduction

It all started from a letter Albert Einstein wrote in late 1930’s to President Franklin D Roosevelt (FDR) about the power of nuclear fission. FDR was told at that point that Adolf Hitler had his best physicists working on it already, and the Nazis had taken over control of Uranium mines, which were essential for nuclear fission weapons. FDR placed emergency funds together to put Manhattan Project into motion to counter the Nazis.

At that point, it was win or die as the Nazis were rolling through Poland and every other bordering countries using the dominant aggressive strategy of blitzkrieg. If Nazis had built the nuclear bomb first, there is no doubt the war would have ended within weeks as Hitler would have wiped out many great cities such as London, New York City, Moscow, and perhaps Washington DC within days. The Nazis already had plans on paper for an all-out invasion of United Kingdom – the nuke would have been the game-changer.

With London out of the way, Nazis would have control over all of Europe, which had not been done since the Roman Empire more than 1,500 years earlier. United States & Soviets would be left fighting on their own, while isolated from each other by a vast Pacific Ocean. Anyone that refused to surrender would be in danger of nuclear obliteration, much like Japan’s Hiroshima and Nagasaki were. There is no doubt the Axis powers would have won the war if they had gotten the nukes first.

Einstein was a pacifist, but he was also a realist. He understood he had no choice in the matter – the Nazis had good scientists working on the nuke already and very aggressive leadership from top to bottom. He knew the Nazis would wipe out millions & entire nations if they got the nuclear bomb first.

Before the 1930’s, Einstein had changed the world of physics with his theory of relativity and was greatly respected throughout the world. His work in the 1910’s had led to the beginning of the field of nuclear physics so in some ways, he had responsibility as the one whose work led to the nuclear era. As smart as Einstein was, he was no nuclear physicist as it was a brand new field. Other scientists specializing in it had more experience in that field, but the respect Einstein had gained made everyone listen when he spoke. Other nuclear physicists came up to Einstein and asked him to be the one to write to President Roosevelt since they knew Roosevelt would listen to Einstein more than anyone else in the world. Einstein agreed to do it and wrote the letter (below).

Einstein letter to Roosevelt - click to zoom

Einstein letter to Roosevelt – click to zoom

 

Everything changed after that single short letter by Albert Einstein. Unknown to anyone at that time, the cat was out of the box. Permanently.

Manhattan Project

The project itself was led by General Leslie Groves of the US Army Corps of Engineers and theoretical physicist J Robert Oppenheimer, who was the head of the Los Alamos facility where the nukes were designed and made. Scientists from various Universities were recruited along with bomb experts. The Army Corps of Engineers had expertise so some were recruited from there. There was no time to spare on the resources and personnel.

Entire new technologies and factories were invented on the fly within very short periods necessary for the creation of the nukes. The scientists and engineers basically had blank check to spend whatever money and resources necessary. It was estimated afterwards that over $2 billion dollars were spent (equal to over $23 billion today), which was unheard of at the time.

Facilities built for Manhattan project - CC

Facilities built for Manhattan project – CC

The advantage that USA had was isolation. Mainland USA was essentially untouched by the war even after Japan forced USA to enter war as it was too far away for the Nazis to orchestrate bombing runs using their destructive powerful Luftwaffe. The Japanese were too busy in the Pacific fighting the massive US aircraft carriers to have any shot at a mainland attack. USA was in great position to slowly build up her massive forces for a war that everyone knew was to come.

All of those factors made the research and preparation of Manhattan Project possible.

So how did it work? The physics involved is fairly straight-forward. Nuclear fission requires radioactive uranium to be used. Plutonium is also used, but it is slightly more unstable & more difficult to obtain. Uranium is easier to extract and also more exists to begin with than Plutonium. Therefore, Uranium is used more.

Uranium has many protons & neutrons in its core (U-235 has 143 neutrons and 92 protons). The moment you split that atom, large amounts of energy is released. Just a small amount of Uranium would release tremendous amounts of energy in the form of heat, gamma rays, and other particles. It gets so hot that everything melts instantly within a certain radius depending on the bomb. In fact, the heat from the explosion will even exceed that of the center of our sun.

Once a neutron is fired into an Uranium-235 atom, the Uranium gets split into two separate atoms. The separation exerts energy, and more neutrons get thrown outwards from that one atom. Other Uranium atoms absorb those neutrons, and they also split into separate atoms while shooting out their own neutrons. It leads to a massive chain reaction where the bomb implodes into a massive explosion more powerful than anything (HowStuffWorks).

Trinity bomb test - first nuclear explosion in history

Trinity bomb test – first nuclear explosion in history

At the conclusion of Manhattan Project, a total of 4 bombs were made. Trinity, Little Boy, Fat Man, and a fourth bomb that was to be used on Japan (maybe Tokyo?), but it was not necessary as Japan surrendered. Trinity was for testing purposes to see the effects of it in a test scenario, and it was the first nuclear fission bomb ever tested.

Here’s a compilation of various later nuclear bomb tests, such as the Soviet Union’s Tsar Bomba. Tsar Bomba was by far the largest nuclear bomb ever tested using nuclear fusion at over 50 megatons, which would incinerate everything within 15 mile (25 kilometer) radius.

According to Modern Marvels, there are total of 30,000 nuclear warheads globally today with ALL but 200 in the hands of USA and Russia.

Conclusion

The Manhattan Project was the beginning of an era that redefined not just how we wage war but humanity itself. Do note that there were not just negative destructive impacts, but there were also some positives.

-Some sort of deterrence was set that prevented an all out war between USA and the Soviet Union and millions of death. Without the deterrence and fear, there is a good chance things would have blown up between the two nations into a war. The fear of one country using nukes was too great so nobody used it. I truly believe it is a disappointing aspect of humanity that we have to rely on the power of deterrence to not wage war instead of defining the mindset itself to not wage war.

-We got nuclear energy that changed how and where we get our energy from. Even though they used nuclear fission in Trinity, Little Boy, and Fat Man, it eventually led to the hydrogen bomb using nuclear fusion just 6 years later. Nuclear fusion is the future of the energy source that humans will use as I blogged about in more depth here: Nuclear fusion Energy Source

-Gained better understanding of nuclear physics and gained overwhelming amounts of data to grasp a fraction of the power of the cosmos. We also gained better understanding of our place in the cosmos and the origins of complex elements that eventually led to our existence. I blogged about that here: How Complex Elements Came to Be

-Gained new technologies that were thought to be impossible before or simply out of reach. These further expanded our understanding of the world

Next week, I blog about the nuclear bombs used on Japan as second part to this blog entry: Bombing of Japan.

Harsh Shukla
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