## Neutron stars

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.

 PhysOrg.com science news on PhysOrg.com >> Heat-related deaths in Manhattan projected to rise>> Dire outlook despite global warming 'pause': study>> Sea level influenced tropical climate during the last ice age
 Recognitions: Gold Member Science Advisor Staff Emeritus What you must assume is that the wntire mass of the sun gets condensed into an extrememly dense neutron core. You are given the density of a neutron star and thus it is easy to relate the mass to the volume and thus the radius as you assume the sun will condense into a sphere. $$\rho_{core} = \frac{m_{sun}}{\frac{4}{3}\pi r^3}$$