A bomb so powerful
it could destroy an entire city
sounded like fiction prior to World War II.
But then, on August 6 and 9, 1945, respectively,
the first Atomic bombs were dropped on Hiroshima and Nagasaki,
destroying these cities and killing an estimated 200,000 people.
This was the start of a new age with a bomb so powerful
it would change everything.
Since then, nuclear weapons have evolved significantly.
If you thought the nuclear bombs from 1945 were scary,
wait till you hear how powerful nuclear bombs are nowadays.
This is the Evolution of Nuclear Weapons!
The origins leading up to the discovery of nuclear weapons started in 1898
when Pierre and Marie Curie discovered an ore of uranium contained in a substance which they called radium.
It emitted large amounts of radioactivity.
Meanwhile, Ernest Rutherford and Frederick Soddy identified that atoms were breaking down and turning into different elements.
This moment was seen as a eureka moment among scientists
knowing that the elements could contain incredible amounts of energy just waiting to be harnessed.
And they were right…
In 1933, the Nazis came to power in Germany, and they restricted Jewish scientists from doing their jobs.
Many of them had to flee the country, and amongst them was Leo Szilard.
Leo fled to London, and it was there where he patented the idea of a nuclear chain reaction via neutrons.
Leo's patent also introduced the term "critical mass,"
which described the minimum amount of material required to sustain the chain reaction and its potential to cause an explosion.
However, the patent was not about an atomic bomb;
it just speculated the possibility of a chain reaction.
Leo already knew it would have great potential to be dangerous,
"If we manage to get through the next 15 years, and be still alive,
We'll probably emerge the immune atomic bombs."
and later he would become an incredibly important figure in the development of the atomic bomb,
which we’ll discuss later in this video.
By 1938, two German chemists discovered a new element called barium after bombarding uranium with neutrons.
Two Austrian physicists gave this process the name “fission,”
and this process would be key to developing a nuclear bomb.
So let’s do a little physics here.
When an atom of radioactive material splits into lighter atoms, there’s a sudden, powerful release of energy.
And so, the discovery of “nuclear fission” opened up the possibility of nuclear technologies, including weapons.
In August 1939, a month before World War II started,
Leo Szilard wrote a letter to US President Franklin D. Roosevelt, warning that Nazis might develop atomic bombs
and suggested that the United States should stockpile uranium ore and start its own nuclear program.
Roosevelt responded by setting up the Uranium Committee.
However, it wasn’t taken very seriously as initial funding was as low as $6,000.
Fun Fact
The letter written by Leo Szilard to urge the United States to start its own nuclear program
was signed by none other than Albert Einstein.
In 1947, Einstein admitted that he regretted signing the letter and was quoted saying,
The world’s first nuclear weapon program was started by Britain and Canada as part of the Tube Alloys project.
Physicists Otto Frisch and Rudolf Peierls discovered that a uranium bomb would be possible and stated,
During World War II, both sides were fully aware of the possibility of nuclear weapons,
but no one was quite sure how they could be engineered.
It was frightening that no one knew how far the Nazis were in creating an atomic bomb.
Fun Fact
The Nazis were incredibly far with their weapon technologies.
One of the weapons they created was the V2,
the world’s first long-range guided ballistic missile, dubbed the “Vengeance weapon”…
Werner von Braun was a leading figure in creating the V2, and after World War II, he was captured by the United States
including 1,600 other Nazi German scientist, engineers, and technicians.
In the US, Von Braun continued developing rockets, but this time for NASA.
He became incredibly important for developing the Saturn V, as he was the chief architect.
Von Braun is widely seen as the “father of space travel” or the “father of rocket science.”
If you like to know more, we talk about it extensively in the Evolution of NASA.
The Manhattan Project began modestly in 1939, but when the Japanese bombed Pearl Harbor on December 7, 1941,
the United States became involved in World War II, and it quickly turned into a massive project.
In fact, it grew to employ more than 130,000 people spread across 30 different sites.
The total cost of the Manhattan project was nearly $2 billion,
which would be equivalent to more than $31 billion today!
While the project was led by the United States, it also received support from the United Kingdom and Canada.
The three primary locations of the Manhattan Project were Richland and Oak Ridge, but the most notable location was Los Alamos,
which was the “think tank” of the project.
Nuclear physicist Robert Oppenheimer became the director of the Los Alamos Laboratory,
an incredibly secret place where they tried to create a bomb more powerful than ever before.
Bombs would be created either using the fissile isotope uranium-235 or plutonium-239.
The production of these isotopes was an enormous undertaking given the technology of the 1940s
and accounted for 90% of the total costs of the Manhattan Project.
Fun Fact
Did you know that residents of the Los Alamos Laboratory lived highly restricted lives?
Their mail was censored, their phone calls were monitored, and even their interaction with family members was tightly controlled.
During the Manhattan Project, two types of atomic bombs were designed concurrently.
The first was a relatively simple gun-type fission weapon.
It had an explosive charge that would fire a uranium bullet inside a gun barrel and start a nuclear explosion.
The second was a much more complex implosion-type nuclear weapon.
As the name suggests, it creates an implosion using conventional explosives.
This results in the Plutonium core being compressed, which allows the chain reaction to occur and causes a nuclear explosion.
The first nuclear bomb created was named ‘Thin Man.’
It was 17 feet long and would weigh about a whopping 8,000 pounds.
It was so heavy that, at the time, no US aircraft was capable of carrying Thin Man without being modified.
However, Thin Man proved to be impractical as the gun would melt instead of explode.
So they developed a new bomb named “The Gadget.”
Even though they tried to keep the design as simple as possible, it still looks like something out of a Sci-Fi movie.
The Gadget was hoisted on a 30-meter tall steel tower.
The height would better indicate how the bomb would behave when dropped from a bomber,
as detonation in the air would maximize the amount of energy applied to the target
since the explosion expands in a spherical shape.
No one knew what to expect when The Gadget exploded.
While some thought it would fail, other scientists like Edward Teller were optimistic.
He put on sunglasses, wore gloves, and put on suntan lotion to prepare himself for this historical moment.
On July 16, 1945, it was time to detonate the bomb, with the code name “Trinity” given to the nuclear test.
The explosion was massive, unlike anything they had ever seen before.
It caused a massive shock wave and a heat wave that was reported as “being as hot as an oven.”
A huge mushroom cloud followed that reached 7.5 miles in height.
They knew the world would never be the same.
As a reaction to the explosion, some people laughed, and others cried,
but most were shocked and completely silent.
After the explosion, Oppenheimer thought of a line from Hindu scripture.
"Now I am become Death, the destroyer of worlds."
Fun Fact
Before exploding the bomb, observers set up a betting pool on the results of the test.
Oppenheimer betted the bomb would have a power of 0.3 kilotons of TNT.
Well, he wasn’t even close...
The bomb was massive, with an explosive energy of 25 kilotons of TNT.
That’s more than 833 times as powerful as Oppenheimer imagined.
Just a few weeks later, the United States had developed the first atomic bomb ready to be used in the war.
It was a uranium gun-type fission bomb nicknamed “Little Boy.”
On August 6, 1945, a B-29 bomber flew over Hiroshima, Japan, and dropped the atomic bomb.
The explosion was massive, everything close to the center was vaporized,
and then a shock wave followed that destroyed everything nearby.
The explosion immediately killed an estimated 80,000 people.
To make things worse, tens of thousands more would die because of radiation exposure.
In total, out of the population of 350,000 people in Hiroshima, roughly 140,000 people were killed.
That’s over 40% of the population!
It wasn’t just the number of deaths that made this so unbelievable since,
on March 9 and 10, 1945, 279 B29 bombers dropped 1,700 bombs on Tokyo, killing well over 100,000 people.
It was the fact that this was just one B29 airplane dropping one bomb, destroying an entire city.
This had never happened in history before.
Newspapers in the United States cheered the atomic bomb, with headlines like “First Atomic Bomb Rocks Japan”
and “Atomic Bomb hits Japan like 20,000 Tons of TNT.”
But even though the devastation of the atomic bomb was massive,
Japan was given the choice to “surrender or face destruction,”
and… well… they rejected the ultimatum.
Meanwhile, the United States had already developed a second atomic bomb.
This time it was a plutonium implosion-type fission bomb nicknamed “Fat Man,” which was almost similar to the Gadget.
Just 3 days after dropping the first atomic bomb, Fat Man was dropped on Nagasaki.
In contrast to Hiroshima, almost all buildings were old-fashioned and definitely not designed to withstand explosions.
Yet again, the nuclear explosion destroyed the city and immediately killed tens of thousands of people.
Interestingly the primary target wasn’t Nagasaki.
The initial target was a city named Kokura.
However, due to thick haze and smoke, plans were changed last minute to bomb Nagasaki instead.
The two atomic bombings killed an estimated 200,000 people, most of whom were civilians.
There were plans for more atomic bombs. In fact, if necessary, the US would keep dropping nuclear bombs as fast as they were built,
which were at the time 3 or 4 a month.
Fortunately, though, on September 2, 1945, Japan surrendered, putting an end to World War II.
Fun Fact
Did you know that Godzilla existed as a metaphor for the pain and destruction caused by the atomic bombs
that were dropped on Hiroshima and Nagasaki?
In the 1954 Japanese film, Godzilla, it was explained that the monster was a prehistoric reptile that was mutated by radiation
from a nuclear test conducted by the US military in the Pacific Ocean.
World War II had ended,
but the development of atomic bombs was just getting started.
During the Cold War, the Soviet Union and the United States were in a very intense arms race
to develop much more powerful atomic bombs.
Click the video onscreen to watch the second episode
to see how much the terrifying Atomic bombs have evolved since World War II.