>Gravitational waves are vibrations in spacetime. They interact very weakly with matter. They travel at more or less the speed of light without 'hitting' any ro

>Gravitational waves are vibrations in spacetime. They interact very weakly with matter. They travel at more or less the speed of light without 'hitting' any rocks. The question is what are the 'rocks' - since gravitational waves don't really interact with matter significantly, and we don't really understand the makeup or source of spacetime. They can have big impact: "The waves can also carry off linear momentum, a possibility that has some interesting implications for astrophysics. After two supermassive black holes coalesce, emission of linear momentum can produce a "kick" with amplitude as large as 4000 km/s. This is fast enough to eject the coalesced black hole completely from its host galaxy. Even if the kick is too small to eject the black hole completely, it can remove it temporarily from the nucleus of the galaxy, after which it will oscillate about the center, eventually coming to rest. A kicked black hole can also carry a star cluster with it, forming a hyper-compact stellar system. Or it may carry gas, allowing the recoiling black hole to appear temporarily as a "naked quasar"[1]. And idk what do you mean by "source of spacetime" you mean quantum origin[2]? https://knowablemagazine.org/article/physical-world/2019/quantum-origin-spacetime https://knowablemagazine.org/article/physical-world/2019/qua... [1] https://en.wikipedia.org/wiki/Gravitational_wave https://en.wikipedia.org/wiki/Gravitational_wave [2] https://knowablemagazine.org/article/physical-world/2019/quantum-origin-spacetime https://knowablemagazine.org/article/physical-world/2019/qua...