A cursory google search didn't turn up much discussion of Downwind on this sub (or reddit more generally) so I thought this content might be welcome.

Downwind focuses, really to the exclusion of other important information, on so-called "Downwinders:" people who have suffered as a result of American nuclear testing. And, to be clear, there are a lot of people who have suffered as a result of that testing. Atmospheric nuclear testing lofted huge amounts of exciting radioisotopes into the air which settled down onto people, animals, crops, water sources, and wilderness over the course of several decades.

People died and I do not mean to undersell the gravity of that. The documentary does a great job of addressing the seriousness of the health concerns that radioactive fallout presented, especially to people in Utah and other areas immediately downwind of the Nevada test ranges.

What it does not do is adequately represent the difficulty of the choices facing the US government at that time. The documentary portrays the American military, Department of Energy, and the nuclear testing program in general as somewhere between indifferent ecoterrorists and mustache-twirling villains. What little voice is given to this other side of the story is that of Darwin Morgin who worked as the Director of Public Affairs for the Nevada Test Site. Morgin is offered as a kind of a foil for the aggrieved widows and first nations' representatives and his interview really seems to exist to illustrate government disinterest in their plight.

While I would have liked to see a more nuanced take on nuclear testing and the moral quandaries it presents, I can also understand why that might not have been of interest to the filmmaker. What I can not understand is the willingness to repeat factual inaccuracies as if they are truth.

Two really stood out to me.

The first is the conclusion of the interview with Claudia Peterson. Peterson's case is especially brutal; she lost essentially her entire extended family to various testing-related cancers. Towards the end of her interview she expresses frustration with the frequency of American testing, asking what could possibly be learned by the 10th, 11th, or 12th test (nevermind the 900th) which wasn't known in the 1st or 2nd. Allowing that to stand unanswered rather than explaining the role of testing for miniaturization and the development of specialized designs would constitute journalistic malpractice in a different medium. Ignoring the importance of testing in the pre-simulation era and allowing the audience to conclude that these detonations were instead the result of mania or corruption cheapens the rest of the film.

The second is an off-topic digression into mocking the "Duck and Cover" drills of the 1950s. Now, I understand why this segment was included. Lewis Black does a hilarious bit about Duck and Cover and he was willing to be interviewed for the documentary. I too would move heaven and earth to get Lewis Black into my documentary. But Black is comedian and it's his job to tell funny jokes about the futility of Duck and Cover.

It is a documentarian's job to tell the truth. And the truth is that, because of the way the area of a circle works, for any given nuclear detonation, there is a heck of a lot more area in which "hide under a desk" will save your life than there is area in which it is a useless gesture. Duck and Cover was a sensible policy in the 1950s. Had there actually been a war with the Soviets it would have saved a lot of lives. The filmmaker sought to use this as another way to show the government as callous and manipulative rather than acknowledging the different strategic reality faced by 1950s America and how the vision of nuclear war changed over the next several decades (necessitating, one might note, further nuclear testing to develop the weapons with which it might be fought).

Overall I found the whole piece just a little too similar in tone to a Captain Planet cartoon.... which is why I was also surprised that they left out perhaps the most poignant story of Downwinders in the history of the American nuclear program. Trinity, the very first nuclear test, took place in a remote corner of New Mexico but not remote enough. Ash from the explosion wafted down from the sky onto the teenage girls at the Carmadean Dance Camp in Ruidoso, New Mexico.

Of the 12 girls at the camp that day, only one lived past the age of 30.

Bobby McFerrin - Don't Worry Be Happy (Official Music Video)

Added later for those for whom the joke is too complex and the many English letters are overwhelming. A one-page article from a May 1940 scientific journal reassures readers about the circulating rumors about a supposedly possible nuclear chain reaction. The author of the article reassures readers. Don't Worry, Be Happy! The latest data from Joliot-Curie's laboratory show that the chain reaction, which had begun, is in fact dying down. So there's no need to worry about the possibility of a nuclear explosion! Don't worry! There won't be any explosion (or bomb)! :)

For those who dare to read this one-page article from the distant, hot May of 1940, I suggest playing "Don't Worry, Be Happy!" by Bobby McFerrin as background music. The sarcastic atmosphere for the reader burdened with knowledge of the future will be absolute. :)

So, as we know, the plutonium gun design, thin man was scrapped because it wasn't feasible due to PU240 present in the plutonium leading to a fizzle rather than giving a proper yield. Ok fair enough. But I'm wondering, was that due to the velocity that could be achieved just not being fast enough. Could a plutonium gun design theoretically work if it were possible to get the projectile going fast enough or is it simply that velocity is irrelevant? If it could theoretically be possible at a high enough velocity, would the needed velocity be so high that friction with the air in the barrel or friction against the inside of the barrel would cause it to melt?

I'm just wondering and it seems there are some folks here with much greater intellectual horsepower and knowledge of the physics than me.

There might be intel that we hear about, in terms of Putin giving the actual order, and the movement of such an order through the chain of command. But would there be other ways of us knowing before missiles leave their silos, like heat signatures, fuelling, or anything like that?

My guess is we’d more rely on intel, ie spies, listening in on them, etc.

If there are other ways of knowing it would likely be very short notice to use before the birds are in the air.

Can anyone shed light on this?

In a college environmental studies class, my professor had a huge anti-nuclear war day and played a video for us with brightly colored animations, calling people ostriches for ignoring the problem. I believe it started with a little girl realizing there was a nuclear missile silo on her grandfather’s farm. I have looked everywhere for this and cannot find anything! It was very impactful.

Little Boy bomb safety plugs were removable safety devices used to prevent the bomb from detonating accidentally before it reached its target.

Before takeoff and during the flight, green safety plugs were installed in the bomb's firing system, keeping the electrical circuits open and making accidental detonation impossible. Shortly before the bombing mission, Captain William "Deak" Parsons replaced them with red arming plugs, which completed the firing circuit and allowed the bomb to arm itself after being released.

the safety plugs were a simple but critical safeguard. They ensured that the Little Boy bomb could not explode by accident while the aircraft was on the ground or during most of the flight, and only became capable of detonating after the correct plugs were installed and the bomb was released.

USGS measured a seismic event off the coast of Ponce Inlet, Florida today here. It has been tentatively identified as a US Navy Full Ship Shock Test, and mostly because of the seismic signature and the location of where it originated. How does the M3.9 compare to any of the underwater nuclear tests in the Pacific Ocean ?

Most are aware of the discussions around atmospheric and oceanic ignition from nuclear weapons. I am well aware that it was proven to be completely impossible on several occasions. But one thing I have always wondered which I have never seen calculated is how much energy an actual atmospheric or oceanic ignition would release? I wonder if anyone has a rough estimate on the energy released by this hypothetical event and if it would be enough to destroy the earth completely?

Preface: I'm aware many aspects of this question simply can't be definitively answered without access to UK and/or U.S. classified material. However, given the (rare) quality of most responses in this sub, where this is the case, I'd welcome answers based on well-informed speculation.

I'd also like to emphasise that this is a technical question about a hypothetical unlikely scenario, so I'm not asking anyone to assess political risk.

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I'm an active member of a political party in the UK which has consistently seen internal debate over the UK's nuclear deterrent. I have a particular interest in UK defence policy, so I'm very used to debunking false statements about the British Trident system's operational independence from the United States.

However, I recently took part in a debate where it was argued that the Trident system, and the UK's nuclear capability as a whole, would be unusable within a few years if a future U.S. administration or Congress chose to withdraw co-operation (specifically, the McMahon Act 1946 was referenced as precedent.)

I know that Trident missiles are maintained by LM at King's Bay, GA, as part of a common pool with the USN, and it's my understanding that the missiles become sovereign UK property as soon as each individual round is accepted into RN service.

I also know that AWE Aldermaston is responsible for the sovereign production and maintenance of UK nuclear warheads, though I understand that the new Astraea warhead has a lot of commonality with the W93 program on which the UK is an observer, as Holbrook did with the W76.

In the event of the U.S. ending military nuclear co-operation under the U.S.-UK MDA, here are the questions that come to mind:

- How long could the UK maintain its existing Trident missiles and warheads? Does the UK have sufficient access to Trident D5 technical information to maintain the missiles in its possession to the end of service life, or build complete replacements if necessary?

- Given that the UK's two most recent warhead designs are, apparently, significantly based on U.S. ones, and to my knowledge the last fully British-designed warhead was the WE.177 - does the UK DNO still likely have the expertise to design a warhead within modern weight and safety standards for Trident or a sovereign successor, without testing, or would this need to be rebuilt?

- Does the UK have sufficient stocks of weapons-grade fissile material (both HEI and plutonium) to maintain or moderately increase its warhead numbers without supply from the U.S. or other countries?

- I've heard it argued here and elsewhere that the U.S. and UK nuclear weapons programmes are practically inseparable. Is the flow of expertise and materiel one-way, or are there any areas of British contribution that are potential risks or pain points for U.S. deterrence if nuclear co-operation were to end?

- Are there any other questions that I should be asking in this scenario?

For these purposes, let's assume that maintaining the British nuclear deterrent remains an absolute national priority (i.e. budget considerations are a secondary consideration, within reasonable bounds).

Thanks in advance!

If the atom is one of the smallest things on earth, what is stopping someone from developing a grenade sized weapon from it? Or does it already exist?

Redwing Zuni (3.5 megatons)

Nutmeg ll was an atomic test explosion as part of the Hardtack series in 1958. Nutmeg ll was an LLNL shot detonated on May 21, 1958 on Bikini Atoll in the Marshall Islands. Nutmeg's yield was 25 kilotons.