So I understand that as a star begins to die, and begins fusion of H, He, C, O... it eventually reaches Fe which cannot be fused to create energy. Then the stars own gravity overcomes it's outward radiation and the star implodes, and eventually a black hole is created. How can the star's gravitational force increase when it becomes more DENSE. I thought that gravitational force was only related to mass, and distance between centers shown by the formula for Universal Gravitation: F = (Gm1m2)/d^2 . So as the star imploded I don't see how it's gravitational force became stronger, it didn't gain mass through this process, I would assume it lost mass as it fused various elements. It seems as though all that happened is that the star gained density. Could someone please explain this to me, and correct any errors in my question? Thanks!