Ah, so once the byproducts are again at rest with 0 kinetic energy, total mass of the system will be equal to total mass of the system before? So the energy of

Ah, so once the byproducts are again at rest with 0 kinetic energy, total mass of the system will be equal to total mass of the system before? So the energy of the explosion comes purely from the atoms being at a lower energy state than they were as uranium? I suppose it makes sense if it takes a huge outlay of energy to form them, which stars could certainly source. I should go watch some physics OCW...