The inner balls travel faster near the bottom of the screen as opposed to the top, while the outer balls travel slower at the bottom of the screen as opposed to the top. (Note that we are choosing to ...The inner balls travel faster near the bottom of the screen as opposed to the top, while the outer balls travel slower at the bottom of the screen as opposed to the top. (Note that we are choosing to show the complete orbits of the balls, even the ones that would have hit Earth.