> If the wave imparts energy on an object and makes it move The objects don't move. The space between them stretches and compresses. Now, if the gravitational

> If the wave imparts energy on an object and makes it move The objects don't move. The space between them stretches and compresses. Now, if the gravitational wave moves through a large massive object like a star or planet, the electromagnetic forces of the "stuff" in the object will cause it to resist this stretching or compressing. I think this does cause a very very very tiny "backreaction" to the gravitational wave, weakening it slightly.