This very much overstates the certainty of the scientists in the outcome of the explosion. They could be pretty certain it would work - but they were not at all certain about the result of producing energy, pressures, temperature and forces that have never been tested on earthly reality before. There were many unexcepted outcomes of the explosion, we are just lucky (as we usually are with new science) that they weren't particularly bad.

You might be surprised at how little we know about fusion. We can observe the sun, but the sun is already very hot, millions of degrees, so any unknown fusion reactions would have already happened. Nowadays we have high-powered lasers that can create laboratory-scale fusion reactions.

E. O. Lawrence's 1930 cyclotron could generate protons at roughly a million degrees Celsius. But that's a single proton stream. Good for splitting atoms but not for fusing them. You really don't know what the cross section of a fusion reaction is until you do it. The properties of matter at that temperature are just super weird. If it had turned out that there was, e.g., a carbon-carbon fusion reaction with a lower initiation, that might be enough to "go critical" and kick off more fusions, and propagate around the world. According to estimates, the Chicxulub crater was 1-10,000 degrees C. Not even the same ballpark.

https://www2.lbl.gov/abc/wallchart/chapters/11/4.html

> Someone's got to explain to me how this was even remotely plausible.

You need to understand what a nuclear chain reaction is. https://en.wikipedia.org/wiki/Nuclear_chain_reaction

> We've had orders of magnitude more energetic events in earth's history

It isn't about energy. There was never an unbounded nuclear chain reaction of anywhere near this magnitude on the planet before Trinity. A large asteroid impact doesn't cause a nuclear chain reaction at all. The moon impact melted the entire crust but didn't cause a nuclear chain reaction.

In fact, the only chain reaction that happened at all before Fermi's experiment in 1942 - that we know of - was in Oklo (now Gabon) about 1.8 billion years ago. We didn't learn about that until 1972, and anyway that was more like a controlled reactor pile and it only happened because there was so much more Uranium 235 so early in the Earth's history.

The event at Trinity was completely different because so many neutrons were released at exactly the same instant. They had good reasons to be very confident in their models and calculations, but they were not 100% sure, and as TFA points out, the blast was several times more powerful than most models predicted.

We didn't know as much about possible nuclear reactions back then, so I think they thought there was a possibility that there was an exothermic chain involving N or O that could be ignited by the bomb and would be self sustaining. While an asteroid impact is very powerful over large scales, it doesn't create nuclear reactions, so Trinity was indeed a first at that scale.

But, and I'm not sure how much of this they knew back then, we do get bombarded by high-energy cosmic rays, so chances are one of these hypothetical N or O reactions should've already randomly occurred at least in isolated events over the last few billion years if possible.

People that know more about nuclear physics than I do already answered, but I’ll just say that:

1) It’s easy to think about the past in terms of what we now know, and it involves a real effort to put yourself in the shoes of the people living at the time and to imagine the “fog of war” in what they knew. In 1945 nobody had ever tested a nuclear explosion before and there was still all sorts of uncertainty about it. And as one of the other commenters pointed out, in particular there was a lot of uncertainty about how fusion worked.

2) The center of the Trinity fireball did in fact produce hotter temperatures than had ever existed on Earth before. Temperature and energy being different things.

In some sense the final experimental proof that a nuclear explosion would not set off some unanticipated new chain reaction that would destroy the earth - unlikely, but hard to completely disprove - was Trinity itself. Only after Trinity is it obvious and completely proven how the physics actually worked and obvious that there were no additional reaction pathways that got missed. That is a disturbing thought.

There are different versions of the story. In one of them, somebody asked the question whether the atmosphere could ignite, and that was very quickly answered in the negative, but then Oppenheimer mentioned it to the people in Washington, and after that the question recurred periodically because the higher ups got unduly alarmed.

And then of course there are versions making it into a much more dramatic story.

When they were working on the fusion bomb (and Edward Teller was working on fusion full time already during the Manhattan project), it took some years to establish that even the "easy" to fuse deuterium cannot be set of by simply blowing up a fission bomb. The reaction simply did not propagate for any reasonable dimensions of the system. For any other material the energy balance would have been orders of magnitude short of what was required for a propagating fusion burn.

I think the tiny size of a nuclear weapon and very short interval of nuclear reaction before "disassembly" mean that even though the energy release is small compared to an asteroid impact the temperatures are probably much higher.

(I'm not an expert, though, this is a guess)

Dinosaur-slaying asteroid theory comes from 1980s so it probably wouldn't have crossed their minds.

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.

I dunno, ever since that weasel got stuck in it in 2016, things haven't been super great.

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.

I know the Chernobyl fallout had a pretty significant impact on agricultural in the region, but I don't think I've ever heard about anything similar in New Mexico, Texas, Oklahoma, or Colorado. Why not? Surely there is less agricultural activity on the American West than in Eastern Europe, but is that the only reason?

Or as something without a mouth and needing to scream.

Housing price goes down, but there's no maintenance. No shops open nearby, no hospitals, no firemen, no police, no gas stations.

People will flock to cities that still have services. Then the cities will have the same population density as before.

And, in turn, I doubt this.

Humans living through an event where many people are dying will not be calm and happy, they will panic. There will be factions of people trying to survive and hold society together no matter the cost, others who don't believe or agree with these methods and actively resist, as well as those who seek to exploit the chaos.

COVID was a relatively minor example of this, not even close to an extinction event - how pleasant was existence during that time?

If people are comfortable, they will reproduce and not go extinct. Any situation where we die out slowly is gonna be tough.

>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...

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.

1 day ago: https://www.youtube.com/watch?v=V1Y4UR8xqxA

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.

That was one of the secondary points of James Burke's Connections documentary (the primary being the "technology trap"). Scientific discovery begets more scientific discoveries in unpredictable ways because of connections between STEM fields in an ever accelerating chain reaction.

as an example, complex numbers were from the abstract thinking of centuries ago, on which the modern physics derive much value from.

And each of those technologies is 70+ years old now (assuming you count V-2 rockets as spaceships). All, in fact, from the same period of history as far as I understand.

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.

Penderecki did most of the heavy lifting there

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.

It is, as I say, a small list. 100 Suns, of course. Also, American Ground Zero (do not try to read all at once), At Work in the Fields of the Bomb (interviews and portraits of Los Alamos and Livermore weapons scientists), and How to Photograph and Atomic Bomb. I might also include the souvenir book I got at the Nevada test site when we went on the bus tour in 2003.

The precision implosion of the type used on the plutonium core of Trinity (and then Nagasaki) isn't exactly trivial, but a number of nations have pulled it off. I believe the details of the precision explosives and timing for Trinity are still classified.

The Little Boy gun-type detonation of enriched Uranium is indeed fairly trivial, and end for its first use at Hiroshima they were confident enough to deploy it without full scale testing.

Do you have a link?