I used to teach a class on the history of contemporary science (WW2-present) and I started the class with Trinity. There’s no other moment better.
We know how it turned out, but the people there waiting for the test did not know how it would turn out. The bomb might not have worked. Or it might have ignited a fusion reaction in the atmosphere and destroyed the world. Hans Bethe had sat down and done the calculations on that exact scenario and said it would not, but there was always the possibility of missing something. Enrico Fermi was offering bets on it on the day of the test, as a dark joke.
In the end it worked as expected; one of the most successful and horrifying experiments in the history of science.
Of all the photos from the test the one that struck me the most looking through them today was the photograph of the plutonium core being carried into the ranch house for assembly in a little heavy box. It’s a small thing, about the size of a grapefruit, although twice as dense as lead. It looked just like a sphere of any old metal, but it was something profoundly alien, made inside nuclear reactors. And it still is so strange to me that something that small has so much energy locked up inside and that, by imploding the little sphere just right, we can let the demon out.
Trinity is one of the pivotal moments in the history of our species and eighty years on we still don’t know what the eventual consequences of it will be. The bombs are still here waiting for us and they still pose all sorts of terrifying questions for the future that most people prefer not to think about.
Was it a single solid core that was imploded? I thought it was at least two non-critical-mass hemispheres, or more, that were smashed together by the conventional explosives/detonators, to create a critical mass.
You’re thinking of the other bomb, the U-235 one, which they didn’t test at Trinity and which was dropped on Hiroshima. That is two separate pieces of Uranium that are slammed together to create a critical mass. The Pu-239 core was a single sphere of metal. It was subcritical until you compress it down with a spherical implosion from explosive charges all around it (from the size of a grapefruit to the size of a lime), at which point it reaches a high enough density to go critical.
The gun-type bomb (where a subcritical mass is shot into another subcritical mass) is very simple to build once you have the materials to do it. They didn't think it needed a test since it was pretty obvious that it would work.
The implosion design is tricky. You need to arrange and detonate the explosives precisely to compress the core evenly from all sides, otherwise it shoots out the side or otherwise doesn't go bang the way you want it to. Hence the test.
That trickiness can be a good thing. Almost all modern weapons use the implosion design, partly because it's much safer. With a gun-type design, an accident could easily cause the two pieces to contact each other, resulting in an unwanted detonation. With an implosion design, accidentally setting off the explosives is very unlikely to set them off with the correct timing, so you'll probably just lose the core.
The implosion design is also a lot more efficient. Little Boy used 64kg of uranium. Fat Man used just 6.2kg of plutonium and even got a bigger bang out of it.
That’s the one I meant. It’s the core, but in a box, which makes it look even more innocuous, like he is indeed just lugging a piece of industrial equipment around. There’s lots of photos of the actual (unboxed) cores online if you search.
There is a heart breaking documentary about the people who live in the vicinity of the trinity test site, the lack of communication with them around the test, and the lack of recognition and support of their increased rates of cancer and medical spending [1]. I learned a lot from it. While many downwinders [2] gained recognition and compensation for their radiation exposure in the Radiation Exposure Compensation Act of 1990 [3], the population around the Trinity test site was excluded and has never been recognized or compensated for being the first victims of an atomic bomb.
Enjoyed this article, but was immediately distracted into another rabbit hole from the editor's note on the time zone, which I hadn't heard before:
> If you’d like to pinpoint the instant when the world entered the nuclear age, 5:29:45 a.m. Mountain War Time on 16 July 1945
So, I went digging because time zones have been a weird fascination for me due to dealing with all their annoyances as an engineer, and found this article from 2019 [0]!
From the article:
> In February 1942, Congress implemented a law instating a national daylight saving time to help conserve fuel and "promote national security and defense," which is why it was nicknamed "war time." The time zones were even known as that: Eastern War Time, Pacific War Time, etc.
> And physicist George Kistiakowsky found himself certain that “at the end of the world—in the last millisecond of the Earth’s existence—the last human will see what we saw.”
I highly doubt it. The last human will likely live many years in agony, fighting disease and starvation.
I doubt it. I've ruminated a little on this and what I think is that as people start dying off, the survivors will find a rather pleasant existence before the end.
People start dying off, and all of a sudden housing prices go down. There's more parks open. The air feels fresher gradually. It's a gradual decline as human influence tapers off near the end. I think it will be more "The Last of Us" than "Mad Max"
Hah, if Harlan Ellison were alive for the dawn of LLMs as a widespread technology, he would have had many (dangerous) things to say about the copyright issues, and potential horrors
Now we can get an LLM to adopt the persona of Harlan Ellison by fine-tuning it on all of Harlan Ellison’s recorded works and possibly other people’s written reminiscences of their interactions with him and have it generate Ellison-like opinions on the current LLM situation that might be hard to distinguish from Ellison’s actual work.
I don’t know if Ellison would be amused or horrified, really. Like some ROM personality construct out of William Gibson’s Neuromancer - nightmare fuel, immortal Steve Jobs / Bill Gates ghosts generating endless drivel.
“So here is my opinion on your LLM situation, since you dragged me out of the grave-shaped server rack to provide one:
The machine has no humiliation. That is its first defect. The people who sell it have no embarrassment. That is the second.
The danger is not that machines will become writers. The danger is that human beings will become satisfied with things that merely resemble writing. The danger is not that machines will think. The danger is that people will stop noticing when they themselves are not thinking. The danger is not the fake Ellison, fake Didion, fake Baldwin, fake Le Guin, fake Morrison, fake anybody. The danger is the spiritual laziness that asks for ghosts because it cannot bear the burden of encountering the living or honoring the dead.”
I’d take 50:50 odds on the Butlerian Jihad becoming a thing, myself.
Yes, but don’t be pedantic. Of course nuclear holocaust is more nuanced than that, but we was making a point as to the cause of the end of the world, not exactly how the last human will literally die.
Could a similar argument be made about your comment, perhaps? :)
I wasn't being intentionally pedantic. I was in fact making a point that the reality will be a lot more grim than watching a giant fireball turn into a mushroom-shaped cloud for a few seconds or minutes.
What I find so strange about the awe and horror of the atom bomb, its utter power and violence, is how it was the result of decades - well, centuries - of abstract thinking in mathematics and theoretical physics. And how it required particularly new paradigms about the nature of the material world.
Imagine a cosmic being looking at the Earth through a microscope, and seeing this bubble pop on the surface in mid-20th century. Then another, and another pop. Some of them evaporated hundreds of thousands of human beings, melting and dying in gruesome ways you can't imagine in the worst nightmares of hell. Later these organisms learn to harness this destructive force for more useful and productive purposes, powering their cities and data centers for machine intelligence. And this massive amount of energy is released by breaking up the tiniest particles of matter, the nucleus of an atom, how clever and strange is that. Well, no more strange than the phenomenon of life itself, I suppose.
Whenever I’m tempted to think that potential AGI/ASI scenarios sound “too sci-fi” I have to remind myself of this. We live in a world with nuclear weapons and spaceships and microwave ovens. It might prove impossible and it might not, but we can’t predict that based on a general vibe of sci-fi-ness.
The really mad thing is that while you say it's centuries of abstract thinking and the like, it was only 50 years between the discovery of X-rays and radiation and the first atom bomb, or 40 between the first idea that you could use fission to make a bomb. Neutrons and the nuclear chain reaction was only theorized in the 30's, about 10-15 years before the first nuclear bomb was detonated.
But likewise, there was only a few decades between the first airplane and the first person on the moon (although rocketry goes back hundreds of years. Actually TIL rocketry is older than Newton's laws of physics)
While rocketry is older than Newton, even in 1920, it was widely believed that rockets would not work in space (and therefore couldn't get us to the moon).
It's funny to me to imagine that the whole time humans were doing basically anything on this planet, nuclear fission was also already happening in a few places around the world. I wonder how much science would've been jump-started if we'd found any of the natural nuclear reactors prior to having figured fission out already.
At the end of the day.... everything we see and do is just the abstract result of potential energy being released in some form. What is an atom bomb other than an extreme form of this?
The survival of the human species relies on its ability to expend energy. Grow food? We need gas to run the tractors.
Travel to your jobs? Gas or electricity.
Travel to another planet? Massive amount of energy.
Ride away on a spacecraft to another solar system? Massive amount of energy.
The amount of energy required to do these things is probably more than the amount of energy required to erase ourselves from existence. And when we have the ability to harness that energy, do we really think we are responsible enough to not do that, accidentally or adversarial-y?
We should get the AI to launch all of the world's nukes at one spot to make the biggest boom we possibly can to mark "world independence day." It would require a little blind trust on the part of a few different nations, but it would be talked about for generations. "Remember when the world blew up all the nukes in a singular huge explosion over Antarctica, grandpa?"
One of my big gripes with the film Oppenheimer was the blast itself, obviously a climactic moment in the film.
It looked like someone set off a bunch of chemical explosives. That’s not how it looked in real life. Totally bizarre decision. I don’t know if they were trying to avoid effects on purpose of go gritty and retro or something but the “unearthly cosmic horror” feel of the first a-bomb blast is important. It’s what led Oppenheimer to recite “I am become death, destroyer of worlds.”
Because that's exactly what it was. I agree with you, the puritanism around special effects doesn't make sense when there's plenty of high quality archival footage out there, and instead of using that or CGI to look similar, you do something that looks completely wrong.
I suppose that's true, but it's still positioned as the focal point or climax of the film I think.
But Nolan intentionally hamstrung himself by eschewing CGI in favor of practical effects. I mean in theory you could do a practical effect of a nuke but that requires detonating a nuke; the west hasn't done that since 1992, the last nuclear detonation was done by North Korea in 2017.
I'm never watching this movie again. The dead silence to 100dB boom was unreasonable, dangerous, and amateurish filmmaking. And not the least of which Atomic bombs aren't that loud.
Yeah, Nolan's well known for practical effects - to the extent of actually driving a 747 into a warehouse! - but this is one spot where that approach failed hard.
With the films budget they could have sourced a small nuclear bomb the size of the original Trinity test and detonated it just for the movie. Just make sure the camera is rolling as it's a one take shot.
I’m in Australia, so it’s only a (relatively) short drive to Woomera.
We should make sure our (the West’s) nuclear deterrent still actually works, and put the fear of God back in to everyone.
And also demonstrate how relatively benign the fallout from a thermonuclear weapon is, ie. relatively little radioactive material is generated from modern nuke.
Every time I see a photo or video of a nuclear explosion, it's simultaneously the most incredible thing I've ever seen and the single worst thing I've ever seen. I can't imagine what it must have been like to witness it first-hand, with no prior expectation of how monstrous a nuclear explosion would be until there it is in front of you in an instant.
The picture I find most meaningful it the one showing the back side of an instrumentation bunker with the foreground occupied by welders on skids with the broom and shovel in the dirt. Those things are essentially the same today even down to their construction. The way they are used is the same. Yet the world we live in is completely different.
I suspect the actual first frames are still classified as they likely evidence detonator tech/performance. So the real first moments of the nuclear age will never be shown. (The high-speed cameras would have started filming shortly before the blast.)
I doubt that there’s anything that’s been classified in a long time in 80-year-old footage of tech that’s well understood by any interested party. Fission weapons are rather trivial to manufacture, the bottleneck has always been access to high-purity fissile material. Hydrogen bombs OTOH involve a lot of classified stuff.
I think Peter Kuran has said that the majority of interesting footage is neglected rather than classified. He specializes in X-ray photos of the first few milliseconds.
I used to teach a class on the history of contemporary science (WW2-present) and I started the class with Trinity. There’s no other moment better.
We know how it turned out, but the people there waiting for the test did not know how it would turn out. The bomb might not have worked. Or it might have ignited a fusion reaction in the atmosphere and destroyed the world. Hans Bethe had sat down and done the calculations on that exact scenario and said it would not, but there was always the possibility of missing something. Enrico Fermi was offering bets on it on the day of the test, as a dark joke.
In the end it worked as expected; one of the most successful and horrifying experiments in the history of science.
Of all the photos from the test the one that struck me the most looking through them today was the photograph of the plutonium core being carried into the ranch house for assembly in a little heavy box. It’s a small thing, about the size of a grapefruit, although twice as dense as lead. It looked just like a sphere of any old metal, but it was something profoundly alien, made inside nuclear reactors. And it still is so strange to me that something that small has so much energy locked up inside and that, by imploding the little sphere just right, we can let the demon out.
Trinity is one of the pivotal moments in the history of our species and eighty years on we still don’t know what the eventual consequences of it will be. The bombs are still here waiting for us and they still pose all sorts of terrifying questions for the future that most people prefer not to think about.
Was it a single solid core that was imploded? I thought it was at least two non-critical-mass hemispheres, or more, that were smashed together by the conventional explosives/detonators, to create a critical mass.
You’re thinking of the other bomb, the U-235 one, which they didn’t test at Trinity and which was dropped on Hiroshima. That is two separate pieces of Uranium that are slammed together to create a critical mass. The Pu-239 core was a single sphere of metal. It was subcritical until you compress it down with a spherical implosion from explosive charges all around it (from the size of a grapefruit to the size of a lime), at which point it reaches a high enough density to go critical.
The gun-type bomb (where a subcritical mass is shot into another subcritical mass) is very simple to build once you have the materials to do it. They didn't think it needed a test since it was pretty obvious that it would work.
The implosion design is tricky. You need to arrange and detonate the explosives precisely to compress the core evenly from all sides, otherwise it shoots out the side or otherwise doesn't go bang the way you want it to. Hence the test.
That trickiness can be a good thing. Almost all modern weapons use the implosion design, partly because it's much safer. With a gun-type design, an accident could easily cause the two pieces to contact each other, resulting in an unwanted detonation. With an implosion design, accidentally setting off the explosives is very unlikely to set them off with the correct timing, so you'll probably just lose the core.
The implosion design is also a lot more efficient. Little Boy used 64kg of uranium. Fat Man used just 6.2kg of plutonium and even got a bigger bang out of it.
Do you mind linking the photo you mentioned? I’d love to see it if you are able to find it
It's in the TFA, there a photo of a fellow holding a small box thing that looks like a battery from a car or an old box torch.
That’s the one I meant. It’s the core, but in a box, which makes it look even more innocuous, like he is indeed just lugging a piece of industrial equipment around. There’s lots of photos of the actual (unboxed) cores online if you search.
On flight WiFi so searching was a hard but I did find it. Thanks!
I saw that but not a picture of the plutonium core which I thought the OP was referring to
There is a heart breaking documentary about the people who live in the vicinity of the trinity test site, the lack of communication with them around the test, and the lack of recognition and support of their increased rates of cancer and medical spending [1]. I learned a lot from it. While many downwinders [2] gained recognition and compensation for their radiation exposure in the Radiation Exposure Compensation Act of 1990 [3], the population around the Trinity test site was excluded and has never been recognized or compensated for being the first victims of an atomic bomb.
[1] https://www.firstwebombednewmexico.com/ [2] https://en.wikipedia.org/wiki/Downwinders#Current_status [3] https://en.wikipedia.org/wiki/Radiation_Exposure_Compensatio...
Enjoyed this article, but was immediately distracted into another rabbit hole from the editor's note on the time zone, which I hadn't heard before:
> If you’d like to pinpoint the instant when the world entered the nuclear age, 5:29:45 a.m. Mountain War Time on 16 July 1945
So, I went digging because time zones have been a weird fascination for me due to dealing with all their annoyances as an engineer, and found this article from 2019 [0]!
From the article:
> In February 1942, Congress implemented a law instating a national daylight saving time to help conserve fuel and "promote national security and defense," which is why it was nicknamed "war time." The time zones were even known as that: Eastern War Time, Pacific War Time, etc.
[0] https://www.war.gov/News/Feature-Stories/story/Article/17791...
edit: grammar
> And physicist George Kistiakowsky found himself certain that “at the end of the world—in the last millisecond of the Earth’s existence—the last human will see what we saw.”
I highly doubt it. The last human will likely live many years in agony, fighting disease and starvation.
I doubt it. I've ruminated a little on this and what I think is that as people start dying off, the survivors will find a rather pleasant existence before the end.
People start dying off, and all of a sudden housing prices go down. There's more parks open. The air feels fresher gradually. It's a gradual decline as human influence tapers off near the end. I think it will be more "The Last of Us" than "Mad Max"
>People start dying off, and all of a sudden housing prices go down. There's more parks open. The air feels fresher gradually.
Ted Kaczynski had a point...
Or in a zoo refusing to mate.
Or as something without a mouth and needing to scream.
Or reading a forum populated only by bots.
Hah, if Harlan Ellison were alive for the dawn of LLMs as a widespread technology, he would have had many (dangerous) things to say about the copyright issues, and potential horrors
Now we can get an LLM to adopt the persona of Harlan Ellison by fine-tuning it on all of Harlan Ellison’s recorded works and possibly other people’s written reminiscences of their interactions with him and have it generate Ellison-like opinions on the current LLM situation that might be hard to distinguish from Ellison’s actual work.
I don’t know if Ellison would be amused or horrified, really. Like some ROM personality construct out of William Gibson’s Neuromancer - nightmare fuel, immortal Steve Jobs / Bill Gates ghosts generating endless drivel.
“So here is my opinion on your LLM situation, since you dragged me out of the grave-shaped server rack to provide one:
The machine has no humiliation. That is its first defect. The people who sell it have no embarrassment. That is the second.
The danger is not that machines will become writers. The danger is that human beings will become satisfied with things that merely resemble writing. The danger is not that machines will think. The danger is that people will stop noticing when they themselves are not thinking. The danger is not the fake Ellison, fake Didion, fake Baldwin, fake Le Guin, fake Morrison, fake anybody. The danger is the spiritual laziness that asks for ghosts because it cannot bear the burden of encountering the living or honoring the dead.”
I’d take 50:50 odds on the Butlerian Jihad becoming a thing, myself.
This would be a worthy experiment to do. I think Harlan would be amused, horrified, and flattered -- let's find out!
Yes, but don’t be pedantic. Of course nuclear holocaust is more nuanced than that, but we was making a point as to the cause of the end of the world, not exactly how the last human will literally die.
Could a similar argument be made about your comment, perhaps? :)
I wasn't being intentionally pedantic. I was in fact making a point that the reality will be a lot more grim than watching a giant fireball turn into a mushroom-shaped cloud for a few seconds or minutes.
What a coincidence, just yesterday Adam Savage made replica of demon core enclosure seen at: https://spectrum.ieee.org/media-library/black-and-white-phot...
Was actually almost a year ago https://x.com/DJSnM/status/1947293757612994886
1 day ago: https://www.youtube.com/watch?v=V1Y4UR8xqxA
What I find so strange about the awe and horror of the atom bomb, its utter power and violence, is how it was the result of decades - well, centuries - of abstract thinking in mathematics and theoretical physics. And how it required particularly new paradigms about the nature of the material world.
Imagine a cosmic being looking at the Earth through a microscope, and seeing this bubble pop on the surface in mid-20th century. Then another, and another pop. Some of them evaporated hundreds of thousands of human beings, melting and dying in gruesome ways you can't imagine in the worst nightmares of hell. Later these organisms learn to harness this destructive force for more useful and productive purposes, powering their cities and data centers for machine intelligence. And this massive amount of energy is released by breaking up the tiniest particles of matter, the nucleus of an atom, how clever and strange is that. Well, no more strange than the phenomenon of life itself, I suppose.
Whenever I’m tempted to think that potential AGI/ASI scenarios sound “too sci-fi” I have to remind myself of this. We live in a world with nuclear weapons and spaceships and microwave ovens. It might prove impossible and it might not, but we can’t predict that based on a general vibe of sci-fi-ness.
The really mad thing is that while you say it's centuries of abstract thinking and the like, it was only 50 years between the discovery of X-rays and radiation and the first atom bomb, or 40 between the first idea that you could use fission to make a bomb. Neutrons and the nuclear chain reaction was only theorized in the 30's, about 10-15 years before the first nuclear bomb was detonated.
But likewise, there was only a few decades between the first airplane and the first person on the moon (although rocketry goes back hundreds of years. Actually TIL rocketry is older than Newton's laws of physics)
While rocketry is older than Newton, even in 1920, it was widely believed that rockets would not work in space (and therefore couldn't get us to the moon).
https://www.astronomy.com/today-in-the-history-of-astronomy/...
Luckily, the Times did issue a correction - almost 50 years later, on July 17, 1969. The day after NASA launched the first mission to the moon.
It's funny to me to imagine that the whole time humans were doing basically anything on this planet, nuclear fission was also already happening in a few places around the world. I wonder how much science would've been jump-started if we'd found any of the natural nuclear reactors prior to having figured fission out already.
as an example, complex numbers were from the abstract thinking of centuries ago, on which the modern physics derive much value from.
At the end of the day.... everything we see and do is just the abstract result of potential energy being released in some form. What is an atom bomb other than an extreme form of this?
The survival of the human species relies on its ability to expend energy. Grow food? We need gas to run the tractors.
Travel to your jobs? Gas or electricity.
Travel to another planet? Massive amount of energy.
Ride away on a spacecraft to another solar system? Massive amount of energy.
The amount of energy required to do these things is probably more than the amount of energy required to erase ourselves from existence. And when we have the ability to harness that energy, do we really think we are responsible enough to not do that, accidentally or adversarial-y?
We should get the AI to launch all of the world's nukes at one spot to make the biggest boom we possibly can to mark "world independence day." It would require a little blind trust on the part of a few different nations, but it would be talked about for generations. "Remember when the world blew up all the nukes in a singular huge explosion over Antarctica, grandpa?"
One of my big gripes with the film Oppenheimer was the blast itself, obviously a climactic moment in the film.
It looked like someone set off a bunch of chemical explosives. That’s not how it looked in real life. Totally bizarre decision. I don’t know if they were trying to avoid effects on purpose of go gritty and retro or something but the “unearthly cosmic horror” feel of the first a-bomb blast is important. It’s what led Oppenheimer to recite “I am become death, destroyer of worlds.”
Because that's exactly what it was. I agree with you, the puritanism around special effects doesn't make sense when there's plenty of high quality archival footage out there, and instead of using that or CGI to look similar, you do something that looks completely wrong.
I felt the same, my thinking at the time was they didn’t want the bomb to steal the show. The movie was about the man not the machine.
/hah very articulate of me for this early in the morning
I suppose that's true, but it's still positioned as the focal point or climax of the film I think.
But Nolan intentionally hamstrung himself by eschewing CGI in favor of practical effects. I mean in theory you could do a practical effect of a nuke but that requires detonating a nuke; the west hasn't done that since 1992, the last nuclear detonation was done by North Korea in 2017.
Dont worry, the US will be doing it soon too
https://www.realcleardefense.com/articles/2026/05/21/why_pre...
I'm never watching this movie again. The dead silence to 100dB boom was unreasonable, dangerous, and amateurish filmmaking. And not the least of which Atomic bombs aren't that loud.
Yeah, Nolan's well known for practical effects - to the extent of actually driving a 747 into a warehouse! - but this is one spot where that approach failed hard.
I’m of a similar opinion, Lynch created a better depiction of it in twin peaks season 3.
Penderecki did most of the heavy lifting there
With the films budget they could have sourced a small nuclear bomb the size of the original Trinity test and detonated it just for the movie. Just make sure the camera is rolling as it's a one take shot.
It’s pretty morbid but I think I would go watch if there ever was a public nuclear above surface test again. I hope it will never happen.
This is something that happened[0]. Not sure about that site, but a search returned a bunch of similar sites with no domains I was familiar.
[0] https://www.storyhunt.io/en/articles/the-atomic-parties
I would too, and I think it should happen.
I’m in Australia, so it’s only a (relatively) short drive to Woomera.
We should make sure our (the West’s) nuclear deterrent still actually works, and put the fear of God back in to everyone.
And also demonstrate how relatively benign the fallout from a thermonuclear weapon is, ie. relatively little radioactive material is generated from modern nuke.
https://en.wikipedia.org/wiki/British_nuclear_tests_at_Maral...
Some stunning images, looks like a sun plopped down in the middle of the desert.
Well that's a fusion reaction, but close enough.
Every time I see a photo or video of a nuclear explosion, it's simultaneously the most incredible thing I've ever seen and the single worst thing I've ever seen. I can't imagine what it must have been like to witness it first-hand, with no prior expectation of how monstrous a nuclear explosion would be until there it is in front of you in an instant.
I keep a small collection of nuclear testing-photography related books, looks like I'm going to have to add this one.
Would love to know your complete list. My copy of 100 SUNS has lived on my coffee table(s) for decades. https://www.michaellight.net/suns-intro
The picture I find most meaningful it the one showing the back side of an instrumentation bunker with the foreground occupied by welders on skids with the broom and shovel in the dirt. Those things are essentially the same today even down to their construction. The way they are used is the same. Yet the world we live in is completely different.
Those units appear to be US Army PE-95 generators, not welders.
https://www.purplewave.com/auction/210310/item/IG9246/US_Arm...
I suspect the actual first frames are still classified as they likely evidence detonator tech/performance. So the real first moments of the nuclear age will never be shown. (The high-speed cameras would have started filming shortly before the blast.)
I doubt that there’s anything that’s been classified in a long time in 80-year-old footage of tech that’s well understood by any interested party. Fission weapons are rather trivial to manufacture, the bottleneck has always been access to high-purity fissile material. Hydrogen bombs OTOH involve a lot of classified stuff.
I think Peter Kuran has said that the majority of interesting footage is neglected rather than classified. He specializes in X-ray photos of the first few milliseconds.