The speed of light isn't changed. The distance the light is traveling is what changes. So to: > So when we say that a star is N light years away and therefore

The speed of light isn't changed. The distance the light is traveling is what changes. So to: > So when we say that a star is N light years away and therefore it would take N years to reach at the speed of light, is that not true? Sort of, sort of not. The distance distortion caused by gravitational waves is way too small to make a difference. You're talking maybe nanoseconds sooner or later you'd arrive compared to prediction. But this is true within gravitationally bound regions of space, that is, regions with sufficient mass density to prevent expansion. It's the regions between galaxies and especially between galactic clusters that is expanding rapidly, because insufficient mass density exists in these regions to slow it or stop it. So if you set out for Proxima Centauri, you'll get there in about the amount of time you'd expect. But if you set out to leave the local supercluster to some destination in a different supercluster that is megaparsecs outside of the Milky Way, you may never get there at all, even at the speed of light, because the best cosmological model we currently have predicts the expansion rate between superclusters will eventually exceed the speed of light. [Future of an expanding universe](https://en.wikipedia.org/wiki/Future_of_an_expanding_universe https://en.wikipedia.org/wiki/Future_of_an_expanding_univers...) seems to suggest this will happen in about 150 billion years. Earth won't exist by then, but any signal sent from within any location in the local group outside of it will never arrive anywhere else if its sent past that time. Note the other comment's point that some astronomical features are actually moving toward us is only true within the local group. All supercluster-sized mass regions are receding from all others.