Juggling Plutonium

Assuming that the ball of plutonium that appears in ep two of season one of Alias has a diameter of ten centimeters, then if it is non-hollow, it has a volume of 523 cc. Given a density of 19.8 g/cc, that means that the sphere should weigh in at around 10kg which, fortunately, is roughly inline with the amount of Pu required for criticality, which suggests that the ball is indeed solid.

So, my question is, how exactly is it that Sydney manages to hold something quite so heavy between finger and thumb? This, it seems to me, is most implausible. The fact that she's holding a piece of radioactive material protected by nothing more than a pair of gloves and a veil, however, I find perfectly reasonable...