What happens to a body experiencing a gravitational wave? Suppose I put a ball in the path of a GR wave. As the wave passes through it, the space will expand and contract. This means that the space between every point in the ball should expand and contract. But what will be the reference point I should consider while looking at such king of deformation? Also what happens to the distances between electrons and nucleus inside every atom? I have a very amateur knowledge about this subject. If someone has good links for explanations please post.