The metaphor used by the atheist regarding a string connecting two balls is not an accurate representation of the gravitational interaction between the Earth and the Moon. In reality, the gravitational force between the Earth and the Moon is what keeps the Moon in orbit around the Earth.
Gravity is a force that acts between any two objects with mass. In the case of the Earth and the Moon, their masses and the distance between them determine the strength of the gravitational force. The Moon is constantly falling towards the Earth due to gravity but also has sufficient tangential velocity to keep it in a stable orbit.
There is no physical string connecting the Earth and the Moon. Rather, their gravitational attraction keeps the Moon in its orbit. This gravitational force allows the Moon to continuously fall towards the Earth without actually colliding with it.
So, the metaphor of a string connecting the Earth and the Moon is not a valid explanation for their relationship. It's important to rely on scientific understanding and concepts, such as gravity, to explain the dynamics of celestial bodies.