What is the vertical asymptote of the force of gravity between two objects?

Step-by-step explanation:

For two objects with a finite constant mass, Fg is inversely proportional to the square of the distance between them. As r gets smaller the gravitational force increases. When the two objects are touching Fg is highest. But the mass of an object is focussed at its centre, the centre of mass. When the objects are touching their centres of mass are still separated. The graph has a vertical asymptote at r=0, implying an infinite gravitational force.