https://en.m.wikipedia.org/wiki/List_of_gravitational_wave_observations https://en.m.wikipedia.org/wiki/List_of_gravitational_wave_o... Seems well within range

https://en.m.wikipedia.org/wiki/List_of_gravitational_wave_observations https://en.m.wikipedia.org/wiki/List_of_gravitational_wave_o... Seems well within range; and yes they travel at C - there have been some LIGO observations that were successfully correlated with more traditional (e.g. optical or radio) observations.