The equation for Swarzschild’s radius, the size at which a mass can be considered a black hole, is:
Rgrav = 2GM/c21
1 http://casswww.ucsd.edu/archive/public/tutorial/GR.html
Now, consider the sun for a moment. It has a mass of 1.98892 x1033kg.
a) If it were to become a black hole, what size would it have to shrink to?
b) The ‘typical’ black hole has a radius of about 30km. How many times larger than the sun’s mass
would a ‘typical’ black hole be?