In contrast, the first allied nuclear reactor was a literal pile of uranium and graphite on a squash court.

[0] The Bastard Brigade (great book on all of this)

[1] https://en.wikipedia.org/wiki/Chicago_Pile-1

[1] https://en.wikipedia.org/wiki/Kon-Tiki_expedition

As a snowboarder I was reluctant, but got into it a few years ago. We pull our young daughter in a chariot with skis about 10km into a little cabin by a river with a wood stove.

Cheese, salami and hot chocolate and we make the return loop. Three evenings a week all winter long is a great way to spend time outside.

Two isotopes were used for fission bombs in WWII: Uranium 235 and Plutonium. More than 99% of naturally occurring Uranium is Uranium 238, which will not sustain a chain reaction necessary for a bomb. There are only trace amounts of Plutonium in nature, but it can be produced in reactors that use U238 for fuel. So, to make a fission bomb you need to either separate U235 from U238 or build a reactor to create Plutonium.

It's worth noting that the shortage of heavy water was no accident. The Allies sabotaged the heavy water production facility in Norway that Germany relied on[1].

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[1]https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage

[1] https://en.wikipedia.org/wiki/Chicago_Pile-1 [2] https://en.wikipedia.org/wiki/Hanford_Site

Phew, that underground mission was more important than I thought!

(how many nations had 14,700 tons of silver lying around)

This makes me think about the pervasive classification and paranoia in the "defense" contractors supporting the US Department of "Defense". Any information that's classified, even at the lowest "confidential" level, is only provided on a "need-to-know" basis. And unclassified projects are sort of looked down on, so there's a perverse incentive to classify more than necessary. This "secretive, isolationist approach" seems like it probably prevents a lot of groups from "sharing information or resources", in the article's words (though it concludes that wasn't the biggest problem facing the German effort).

When sharing classified information that someone might not need to know might be a crime, and might get your clearance pulled even if it's not, the incentives run strongly counter to sharing information. Consequently, I confidently claim that there are very, very few people in a position to serendipitously make significant discoveries that involve combining two or three different classified facts.

(I don't actually know this, because I don't know any classified facts.)

Maybe this is part of the sclerosis that causes the US defense-industrial complex to "basically produce useless junk", in the words of Les Earnest (https://www.youtube.com/watch?v=Ych6pvLMKCU), and which prompts Sergey Tovkach to say, "There isn’t a single Western drone that’s proven itself effective in this conflict." (https://www.youtube.com/watch?v=RmfNUM2CbbM). Maybe that's why Russian propaganda in 02024 reported that Ukraine had to withdraw the USA-made M1A1 tanks far from the front (https://www.youtube.com/watch?v=aCIN-t3VxJ0).

From the Farm Hall transcripts, it seems that Heisenberg was "happy" to have been working on a reactor and not a bomb, but from context, this seems less like an objection to the principle of working on a weapon and more like gratitude that the Allies couldn't hang him for working on an atomic bomb. Recall that the conversations took place after Germany had been utterly defeated and the scientists were prisoners at the mercy of the British--prisoners in a gilded cage, but prisoners nonetheless.