How do the detectors work? In my mind they don&#x27;t make physical sense. They&#x27;re saying the distance between the mirrors changes, but I don&#x27;t understand how that&#x27;s possible in this context.<p>Let&#x27;s say a gravitational wave compresses space. To someone inside that compressed space, there should be no noticeable difference. Light will still flow the same way through the compressed space at the same speed <i>relative to the compression</i>. Matter will behave identically, because both light and matter are part of the fabric of that space. As I understand it, the only way the mirror lengths could change is if space is created or destroyed.<p>If that doesn&#x27;t make sense, consider the 2d analogy of drawings living on paper. Assume also that light moves only along the surface of the paper. If you bend the paper, the light will bend with it. But when you bend the paper, the creatures living on the paper can&#x27;t know it&#x27;s bent. The fabric of the paper is still identical. Even if some of the paper gets compressed in one direction, it will still have the same amount of particles, so any light travelling through there will hit the same amount of resistance. And stretching the paper, even if you&#x27;re a drawing on the part being stretched, would have no effect. A 2d creature looking at something 1 foot away, even if the paper is stretched to 10 feet, won&#x27;t see any difference, because the fabric light travels through is also stretched.<p>The only way I can see this making sense is if light travels independent of the fabric of space, but it&#x27;s my understanding that light travels <i>through</i> it, not independent of it?