A perfectly absorbing solid sphere with a known fixed density, hovers stationary above the sun. This is because the gravitational attraction of the sun is balanced by the pressure due to the sun’s light. Assume the sun is far enough away so that it closely approximates a point source of light. Find the radius of the sphere and prove that it is independent of the distance of the sphere from the Sun.

Answer

`R = (3p_("sun"))/(16picdGM_("sun"))`