Brace yourselves for gravitational waves

[Excited Penguin]

Just one thing I couldn't wrap my head around at all. What are these deviations you keep referring to, exactly?

Imagine objects floating at rest in space arranged like the corners of a cube. The metric tensor might tell you that the distance going from one to the other is always x. Now, when the values of the metric tensor change a bit, for example because a grav. wave is coming through, the prescription how to calculate distances between the objects changes (without them having moved!), so the theory predicts that they might suddenly have somewhat larger or smaller distance. This is exactly what LIGO observed. Your eight objects can change relative distance or angles

Fascinating.