Colliding pool balls?

Question

What actually happens at an atomic level when two pool balls collide headon I dont want to know about the trajectory, just the subatomic point of contact ( if there is any )

Answer 1

As Carl Sagan was fond of saying, matter is composed mostly of empty space. The nucleus of the atom is tiny, and surrounded by a cloud of electrons. It is this electron cloud that interacts with the clouds of other atoms. Electron bonds are formed by two atoms sharing electrons. This bond acts very much like a spring. If you try to pull the bonded atoms apart, they resist and try to pull back together, up to a point. If you pull strongly enough, you break the bond. Likewise, if you push the atoms closer together, the mutual repulsion between the electron clouds (both negatively charged) pushes them apart.

There is a certain spacing at which the atoms prefer to rest. It is different for each pair of atoms. In a solid structure like a billiard ball, you can think of the atoms as being connected in a three-dimensional network of springs. Each atom is connected to two or three other atoms (on average) by a tiny spring.

When the ball collides with another, it does not hit on a single point of contact. On the scale of atoms, not even the most finely-crafted sphere looks spherical. It's a mess of protruding points and furrowed valleys. Several of these protrusions will hit approximately simultaneously, and will be smashed down, until the amount of area in contact becomes large enough for the total repulsion force of all the electron clouds to stop the ball (instantaneously) and reverse its trajectory.

The measure of how stiff and strong these springs are is a measure of the "hardness" of a material.

Answer 2

The balls never actually contanct one and other. The repulsive force between the valence electorns of each ball keep them apart. Once they reach a certain point this there momentum will carry them away from one and other since they could not pass through one and other