In ilie fall of 2002, a group of scientists at Los Alamos National Laboratory determined that ilie critical mass of neptuniwn-237 is about 60 kg. The critical mass of a fissionable material is the minimwn amount iliat must be brought together to start a chain reaction. This element has a density of 19.5 g/cm'. What would be the radius of a sphere of this material iliat has a critical mass?
Please provide some description.