Atomic Expert Explains "Oppenheimer" Bomb Scenes | WIRED
Summary
TLDRThis video script delves into the historical and scientific aspects of the first atomic bomb, focusing on the Trinity test and its implications. It details the meticulous assembly process, the implosion technique, and the potential risks, including atmospheric ignition. The script also touches on the psychological impact of the bomb's detonation and the ethical dilemmas faced by Oppenheimer, highlighting the paradox of pursuing peace through destructive means.
Takeaways
- 🔬 The script discusses the science behind the development of the atomic bomb and the role of J. Robert Oppenheimer.
- 💥 It describes the assembly process of the 'gadget', the first atomic bomb, using high explosive lenses to compress a plutonium core.
- 🍑 The plutonium core is compared to the size of a grapefruit, highlighting the small size of such a powerful weapon.
- 🔍 Detailed descriptions of the implosion process, including the use of a polonium-beryllium sphere to initiate the nuclear reaction.
- 🎥 The script references actual historical footage and photos, emphasizing the authenticity of the depicted assembly and testing process.
- 🏜️ The importance of a controlled environment during the final assembly is stressed, to prevent any deformation of the shock wave.
- 💰 The value of the tamper plug and the delicate operation of placing it around the plutonium core is highlighted, indicating the high stakes involved.
- 🌡️ The script mentions the heat generated by the radioactive plutonium core, adding to the complexity of handling the material.
- 🔌 The necessity of precise timing for the electrical signals to detonate the bomb is explained, emphasizing the technical challenges.
- 👀 The use of welding goggles by Oppenheimer during the Trinity test to protect against the intense brightness of the explosion.
- 🌆 The psychological impact of the bomb's detonation is considered, with the script mentioning the recommendation to drop bombs on Japan at night for maximum effect.
Q & A
What is the historical significance of the 'gadget' mentioned in the script?
-The 'gadget' refers to the first atomic bomb, which was assembled and tested during the Manhattan Project. Its successful detonation at the Trinity test site marked a significant milestone in nuclear weapons development and World War II history.
What were the explosive lenses made of, as described in the script?
-The explosive lenses were made of variants of TNT, which were used to symmetrically compress the plutonium sphere at the heart of the atomic bomb.
Why was the plutonium sphere inside the atomic bomb described as being about the size of a grapefruit?
-The comparison to a grapefruit helps to convey the relatively small size of the plutonium sphere, which was crucial for the implosion process to initiate the nuclear chain reaction.
What was the purpose of the polonium and beryllium sphere inside the plutonium?
-The polonium and beryllium sphere served as a neutron source. When compressed, it would emit neutrons that would initiate the nuclear fission reaction in the plutonium.
What is the 'implosion' method mentioned in the script?
-Implosion is the process by which the atomic bomb's high explosive lenses compress the plutonium core, causing a rapid increase in density and temperature to initiate a nuclear explosion.
Why was the final assembly of the atomic bomb considered so delicate and dangerous?
-The final assembly was delicate because it involved handling highly radioactive and valuable materials with extreme precision. It was dangerous due to the increasing risk of accidental detonation and radiation exposure as the bomb neared completion.
What was the tamper plug, and why was its placement so critical?
-The tamper plug was a component designed to sit around the plutonium core. Its placement was critical because it affected the efficiency of the explosion and was worth a significant amount of money in 1945, making any mistake during its installation potentially very costly.
Why was the plutonium core so radioactive that it was warm to the touch?
-The plutonium core was warm due to the heat generated by its intense radioactivity. The amount of plutonium used in the bomb was sufficient to produce a heat signature of about 80 degrees Fahrenheit.
What was the concern about atmospheric ignition during the Trinity test, and was it ever a realistic threat?
-The concern was that the explosion could cause nitrogen and oxygen in the atmosphere to fuse, potentially triggering a global nuclear fusion reaction. However, later calculations showed that this was highly unlikely, requiring conditions far beyond what was possible with the bomb's yield.
Why were the atomic bombs dropped on Japan at night originally recommended, and why were they dropped in the morning instead?
-Dropping the bombs at night was intended to maximize the psychological impact due to the brightness of the explosions. However, logistical reasons led to the bombs being dropped in the morning to ensure better visibility for the pilots and accuracy in targeting.
What was the actual yield of the Trinity test, and how did it compare to initial estimates?
-The Trinity test yielded the equivalent of 20,000 tons of TNT, which was significantly higher than the initial estimate of 4,000 tons. This demonstrated that the bomb was more powerful than the scientists had anticipated.
What was the scale of the Manhattan Project, and what was its output in terms of material?
-The Manhattan Project was a massive industrial endeavor employing around 500,000 people and costing approximately $2 billion. Despite its scale, the output was minimal: a 6-kilogram plutonium core for the Trinity test, and cores for two additional bombs dropped on Hiroshima and Nagasaki.
What were J. Robert Oppenheimer's feelings about the development and use of atomic bombs after World War II?
-Oppenheimer felt a complex mix of emotions. He regretted the continued development of more and more powerful weapons post-war, fearing that such a path could ultimately endanger civilization itself. He was aware of the potential for devastating wars involving much more powerful bombs.
Outlines
🔬 The Science Behind Nuclear Weapon Assembly
This paragraph delves into the technical aspects of assembling a nuclear weapon, focusing on the historical account of the 'gadget' assembled by Oppenheimer's team. The process involves the use of high explosive lenses to compress a plutonium sphere, which is further surrounded by a polonium-beryllium core to initiate the nuclear chain reaction. The assembly's precision is paramount, with the tamper plug being a critical and expensive component. The paragraph also touches on the challenges faced during the final assembly, including the plutonium core's radioactivity and the difficulties encountered with fitting the core due to temperature discrepancies.
🌌 The Trinity Test: A Historical Milestone
This section of the script recounts the Trinity Test, the first detonation of a nuclear bomb, emphasizing the meticulous documentation and the precautions taken to ensure the test's success. It details the use of nixie tubes for pre-digital number display, the importance of timing in sending high voltage signals to detonators, and the psychological impact of the explosion's brightness. The paragraph also discusses the potential risks of atmospheric ignition and the subsequent reassurances provided by Oppenheimer. The narrative includes descriptions of the bomb's assembly, the test's visual documentation, and the unexpected phenomena observed during the detonation, such as the 'rope trick' effect.
💥 The Implications of Nuclear Testing and Oppenheimer's Legacy
The final paragraph reflects on the broader implications of nuclear testing, particularly the Trinity Test's role in shaping Oppenheimer's legacy and the future of nuclear weapons. It discusses the scale of the Manhattan Project, its resource consumption, and the output of a small amount of highly potent material. The paragraph further explores Oppenheimer's complex character, his initial optimism about peace through war, and his eventual regret over the proliferation of nuclear weapons and the existential threat they posed to humanity. It concludes with a poignant look at the paradox of Oppenheimer's life and the moral dilemmas inherent in the development of nuclear technology.
Mindmap
Keywords
💡Nuclear Weapons
💡Oppenheimer
💡Implosion
💡Plutonium
💡Explosive Lenses
💡Detonators
💡Polonium and Beryllium
💡Tamper Plug
💡Trinity Test
💡Atmospheric Ignition
💡Nixie Tubes
💡Mach Stem
💡Manhattan Project
Highlights
Assembly of the atomic bomb's 'gadget' based on declassified images.
Description of the plutonium sphere and its assembly with explosive lenses.
The necessity of symmetrical compression of the plutonium for the bomb to function.
Use of detonators to initiate a shockwave for the implosion process.
Inclusion of polonium and beryllium to emit neutrons and start the atomic reaction.
Historical footage and its replication in the movie 'Oppenheimer'.
Importance of a controlled environment for the final assembly of the bomb.
The delicate operation and high value of the tamper plug in the bomb assembly.
Radioactive heat and handling of the plutonium core.
The challenge of fitting the plutonium core due to temperature differences.
The stressful responsibility of the person setting up the bomb at the test site.
Concerns of atmospheric ignition and the potential global consequences.
Calculations and reassurances regarding the improbability of atmospheric ignition.
The timing and coordination required for the electrical detonation of the bomb.
Description of the Trinity test's visual documentation and its intensity.
The psychological impact of the bomb's detonation and its brightness.
The paradox of Oppenheimer's role in creating peace through warfare.
The scale of the Manhattan Project and its resources.
Reflection on the moral implications and legacy of the atomic bomb.
Transcripts
[bomb exploding]
- I'm a historian of nuclear weapons.
[bomb exploding]
And today I'm here to talk about the science
behind Oppenheimer.
[upbeat music]
So that's a scene of them assembling the gadget.
This is clearly based on some pictures that have come out,
and they're not a ton of pictures
showing this level of assembly
that have been declassified and released.
All the pictures we have of this are black and white.
The people who actually saw it described it
as being a sort of peach colored, a sort of tan colored.
Each of those wedges are several layers of high explosive.
So there are sort of variants of TNT
called explosive lenses, and they are putting them
around the plutonium sphere that powers the whole thing.
This is about the size of a grapefruit
So plutonium's solid metal.
Imagine you had a piece of steel and I said,
push it on all sides to make it smaller.
You need to shrink it by half its size
exactly symmetrically.
Each of these are the detonators.
When they all go off,
they're gonna start a shockwave through this device.
It's gonna start going in, in, in.
Inside that little sphere of plutonium
is an even tinier sphere of polonium and beryllium.
This thing, if you compress it, will shoot out some neutrons
that's meant to just start the reaction.
You push the whole thing together
and make an atomic bomb explode.
This is called implosion.
One of the things we see in the movie
is the final assembly of the gadget.
This is based on actual footage that was taken at the time.
Even the lighting looks like
in the historic footage that we have.
This is a hundred foot tower.
They have brought the explosive sphere
out to the test site by the tower
and they put a big tent around it.
You need this thing to be as controlled as possible.
If you got a pebble in there, it could deform the shock wave
by just enough to make the whole thing either not work
or not work very well.
So they want this to be a very pristine sort of environment,
which is hard to do when you're in the middle of the desert.
They're putting in in this scene
what's called the tamper plug.
The goal is to have this sit right around the plutonium core
in the middle of the bomb.
This is a delicate operation.
This tamper plug arguably is worth $400 million
in 1945 money.
They don't wanna mess this up,
because once you put the plutonium in there,
every little step of getting it closer to being a bomb
makes it a little bit more dangerous to be around
and radioactively, you know, problematic.
This core is like on the edge of being explosive.
It's also radioactive, it's also hot.
Plutonium in that quantity is so radioactive
that it's about 80 degrees Fahrenheit.
They're dropping it through the center of the bomb.
They've made a sort of trap door basically
into the bomb so that the lens on top can come out.
You can drop this thing in.
In real life, they went to put it in and it didn't fit.
Oh my God, have we totally messed this up?
Wait a minute, wait a minute.
It had to be the right temperature for it to fit.
The outer part was cooler than the inner part was,
and so they had to wait for them
to reach the same temperature,
and then it just slid into place.
So there had to be one person left in the tower
to set it all up at the very end, stay with the bomb,
do the final connections, and then head back.
And this was, of course, a very stressful job.
They had previous mock-ups
that were set off by lightning in the distance,
so they were in a very precarious state here.
There's a scene before the actual Trinity test
where General Groves is asking Oppenheimer
about the possibility of this test destroying the world.
- [Groves] There's a chance that when we push that button,
we destroy the world?
- One of the real concerns was this problem
of what they called atmospheric ignition.
What if the nitrogen and oxygen in the atmosphere
fuse together and release energy?
Could they release enough energy
that that would trigger more nuclear fusion
that then goes over the entire globe
and leaves at a burnt horrible cinder?
Turns out that kind of equation is really hard to do,
but let's imagine that it's like 100 times easier
than we think it is.
We can sort of make very conservative extrapolations
and we find it's probably not gonna happen.
- Chances are near zero.
- Near zero.
- What do you want from theory alone?
- Oppenheimer is giving the correct scientist's answer.
They basically concluded
it would be less than one in 3 million, something like that.
In the 1970s, weapon scientists redid those calculations.
Could you set the earth on fire if you wanted to?
Yes, but you need bombs
that would be hundreds of thousands of times
more explosive than any bombs we ever made.
And you'd need to have a much higher proportion
of the ocean be made out of a rare isotope called deuterium,
a different type of hydrogen.
If you had this, you could indeed turn the earth into a sun.
The detonation took place very late at night.
They wanted to see exactly how bright it was,
and it's gonna be harder to see that in the daytime
when you're competing with the actual sun.
They actually had recommended
that the bombs be dropped on Japan at night
because they would be more psychologically stunning.
But for logistical reasons,
they were dropped in the morning on both of the cities.
So those numbers you see are nixie tubes.
Those are a pre-digital way to display numbers.
It's a very nice period-appropriate touch.
So at this point, the gadget, as they called it,
is fully assembled.
You can tell that because the wires are sticking out the top
on the front, that's called the X Unit,
that's the firing unit, it's assembled.
To set off this kind of bomb,
you have to send a high voltage electrical signal
to 32 separate places at exactly the same time.
Nanosecond tolerances on the timing to have it work right.
And then they have a wire
going all the way back to base camp.
And if you hit the big button on the wire.
- Detonator charged.
- [Alex] You're telling the bomb,
go ahead and explode, and it will.
[nuke exploding]
In the movie Oppenheimer,
the Trinity test is one of the climax moments.
It's ridiculously bright,
much, much brighter than the actual sun.
What Oppenheimer's putting on here are welding goggles,
and these are so dark
that you really can't see anything in them
except something that is as bright as the sun.
There were a few people at the Trinity Test
who'd looked at the explosion
without anything over their eyes.
One of them, by accident, he dropped his goggles,
and one of them on purpose.
They both suffered from what was called flash blindness,
temporary blindness.
You'll see a big dark spot
over your vision for quite some time.
There were people who were relatively close,
thousands of yards.
Oppenheimer in the sort of control bunker,
much closer than a lot of the outlying ones.
Most of the people that were instructed to lay down
away from the blast so that they don't turn around
and either get knocked over or get a face full of dust.
So the Trinity test was heavily, heavily documented
both by pressure gauges and cameras
with telephoto lenses from a very far distance,
but some of them were closer in bunkers.
Anytime you see a closeup
and it's sort of like a wall of fire,
there are shots from the actual Trinity test
that looked pretty similar to that.
Interestingly, on some of the very earliest shots
where they were trying to get
the very first moments of the fireball,
it was hot enough that it burned holes in the film.
This particular shot is interesting
because this is what they call in the business a rope trick.
And they only show up when you can take pictures
that are 1,000 frames per second or something like this.
You have a tower with a bomb on it
and it's got wires stabilizing the tower,
and there's a little tendril of the fireball
that's going faster than the rest
because it's blowing up the wire as it goes down there.
No one at Trinity could have actually seen this.
What you're seeing here is the complex interaction
that happens when the blast wave hits the ground,
goes straight down, bounces back up,
and then intersects with that blast wave coming out.
There's a really big difference
in how the blast wave behaves
from a bomb that's right on the ground
from one that's a little bit in the air.
They want this, what's called the mach stem,
to have a wide area of destruction.
That's how you maximize the blast pressure,
detonating very high above the ground.
They're gonna use that data
to set the altitude of the atomic bomb over Japan.
When they went into the Trinity test,
their sort of best guess
was it would maybe be 4,000 tons of TNT.
It ended up being more powerful than they thought
by a factor of like 5, 20,000 tons of TNT equivalent.
This is enough to destroy a sort of medium-sized city.
If you're a much bigger city, like say New York City,
it's enough to destroy like Midtown.
So this is one of the reasons why Trinity is so important.
It's not just it works.
They find out it works really well.
So the Manhattan Project is this gigantic endeavor.
It's this massive industrial project
and employs like 500,000 people.
It's like 1% of the civilian labor force,
and it cost like $2 billion in their money,
which is like 1% of the whole cost of World War II.
They use 1% of all the electricity in the country
to make these weapons.
They're building an industry in like two and a half years,
and the output of that industry
is a very tiny amount of material.
A 6 kilogram plutonium core, 13.5 pounds,
that's the one they first test at Trinity.
About 64 kilograms, so about 120 something pounds
of highly enriched uranium, uranium 235,
that's for the bomb that's gonna be dropped on Hiroshima.
And then they have one more plutonium core.
That's the one they're gonna end up dropping on Nagasaki.
So all of that effort
is to make these three cores for the bombs.
And they had one more bomb in the pipeline.
They ended up never sending it, the war ended.
Many of these people talked about this
as the best years of their life in some ways.
They had a lot of fun,
and some of them felt quite guilty about that
after Hiroshima and Nagasaki.
Oppenheimer's a really complicated character.
What he said he regretted was that after World War II,
they continued to make more weapons
and they continued to make bigger weapons
and they continued to make the kind of world
that he thought would ultimately put
civilization itself in danger.
- In the years to come,
it will be possible to kill 40 million American people
by the use of atomic bombs in a single night.
- [Alex] He knew in 1945 that there were ideas on the table
for bombs that would be thousands of times more powerful,
and that the nations of the world
could all get them if they wanted them,
and that a war with bombs of that big
could be fatal for the entire species.
And so that's the sort of paradox of Oppenheimer,
this person who wants peace, but he does it through war.
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