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Nazi Germany had no hope of making an atomic bomb, uranium cubes reveal

137 points · 121 comments · xqcgrek2

  1. WalterBright · · focus · HN ↗
    It's generally forgotten that Japan was also developing a nuclear bomb. They were a long ways from making a viable one, though. It was abandoned after the surrender.
    1. fusslo · · focus · HN ↗
      I cant remember which, but a documentary about the bombing of Hiroshima and Nagasaki said that after the first bomb, Japanese scientists were deployed to confirm or deny the US's claim of an atomic weapon.

      If I remember right, the Japanese scientists confirmed signs of an atomic explosion, but the leaders were stuck in a debate as to whether or not to accept the findings

      Maybe someone better educated can correct me if I didn't get that history quite right

      Edit:

      <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Yoshio_Nishina#Atomic_bomb" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Yoshio_Nishina#Atomic_bomb

      <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Bunsaku_Arakatsu" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Bunsaku_Arakatsu (check out his academic advisor!)

      1. Lumich · · focus · HN ↗
        « signs of an atomic explosion »

        I&#x27;m curious. We know that there&#x27;s a lot of energy in the atom. Some of it can be released by fission, which results in fission products, radiation, and heat.

        However, there doesn&#x27;t seem to be anything in the process that would account for any sort of explosion. Radiation doesn&#x27;t contribute. Heat alone is insufficient. In addition, you need an instant and manyfold increase in the volume of matter generated on the other side of the reaction. With TNT, for example, this increase is three orders of magnitude. Fission products are completely insignificant in this respect.

        So nothing comparable exists for nuclear fission, else it would be a problem for reactors. So how can it explode? What is the mechanism?

        1. Someone · · focus · HN ↗
          The extreme radiation of the bomb almost instantly vaporizes everything near it (water in the air, earth, parts of the bomb, etc), expanding it in volume.

          That’s what causes the shockwave.

          As a corollary, having more material around the bomb that can capture some of its radiation means a bigger shockwave, but less radiation further away from the detonation.

          1. Lumich · · focus · HN ↗

            [dead]

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