But a gravitational wave? That’s a distortion of space-time itself — a stretching and squeezing of the fabric of reality, a wave of deformation tearing through the cosmos, warping everything in its path. The monstrous denizens of the intergalactic deep reveal themselves not through the light they emit but by how they stir the space-time we share. When a gravitational wave moves through you, you are, for a moment, a different shape.
Or sound waves, literally pressure waves. We can hear or feel them because they deform our body.