Just curious about the energy/mass relationship and how it factors in when making nuclear weapons. (or hopefully a more peaceful use for such a reaction in the future.) I know manhattan era nukes used plutonium and polonium/ beryllium for fission reaction. Einstein's famous equation would have me believe the heaviest elements would yield much greater energy, fission or fusion. Do current nukes use the heaviest elements? Maybe they are too rare or too hard to isotope? Just curious. maybe its classified anyway.