1. The problem statement, all variables and given/known data Suppose the sun collapses into a neutron star. What will its radius be? The questions also gives some backround explaining that stars fuse hydrogen into helium until they collapse into a neutron star. The protons and electrons fuse into neutrons with the density of nuclear matter. 2. Relevant equations 3. The attempt at a solution I'm not sure exactly how to begin. I am assuming I am supposed to use the number for the density of nuclear matter which is 2.3 * 10^17 kg/m^3 but I do not know where to go from here. It would be nice to just get a hint. Thanks.