I think most of you are missing the point of why I posted this. The idea has a superficial plausibility and what I want to know is whether this could have happened and if not exactly why not. Since none of you know much about fission or fusion you probably don't really know why not other than it sounds silly.
The question is a highly technical one, that might strain the knowledge of anyone expert in the field. At the moment I am trying to get some feedback on sci.physics and will post it if I get some information.
Firstly the Plutonium is technically fissile, this isotope has been ignited before. The question then is whether letting pellets of Plutonium like this with Uranium coatings go down into the enormous pressures of the Jovian atmosphere will cause the material to implode into a nuclear explosion. I don't think anyone here knows this, if they do then I want to see the mathematical formulae that back up their statements. The other question is whether the intense heat would also assist the implosion or make it less likely. Again I want to see mathematical formulae not hand waving.
The third question is whether the shells on the pellets could withstand the high temperatures and pressures and perhaps suddenly implode and assist the explosion. For example they may be crushed and add even pressure to the Plutonium before they melt.
The fourth question is if fission occurs then at what level of pressure does this happen and how much deuterium is at that level? If the pellets fall around the same level and are still together would one being set off ignite the others or would it tend to destroy them first? If all went off still encased in a frame would deuterium that would have seeped into it be pressurised enough to make fusion? What distribution of ellets would be most likely to do this?
The fifth question is if it did then how much of a percentage of deuterium would be around the Plutonium and would it fuse in small amounts and how far would it fuse before the reaction stopped?
The sixth question is how long the pellets would take to fall down to this pressure point, would they be slowed and float down slowly or would they be burned up on impact? As before please provide the mathematical formulae to explain your answer.
If any of this could happen (and I don't know and neither does anyone else that I can see) then how big an explosion in megatons would be needed to make the dark spot?
As far as I can see no one here has the expertise to answer any of these questions beyond hand waving. As to whether this happened or not I have no idea and no doubt Hoagland has no idea either. Nonetheless much of this should be answerable by experts in the field (with formulae) and I consider it to be interesting in understanding more about how fission and fusion works. If you can spare me the additional hand waving rebuttals I will try to find out something specific and post it later.