If gravity propagates at, or less than, the speed of light, and is therefore not instantaneous, does that introduce time delays to gravity? For example: suppose that we, the observer, sit within the future light cone of a massive star, and that the light from that star is due to reach Earth for the first time in 100 years time. Is it theoretically possible that we might we feel a sudden (possibly small but theoretically detectable) gravitational ‘tug’ in 100 years time?
Further: Is it possible that, whilst we might currently sit outside of the future light cone of some a star (for example) - over time, due to expansion of the universe - the future light cone of that star could expands to encompass us – thereby enabling us to observe and be influenced by that previously unobservable and undetectable object?
(Note this is in reference to the expansion of the universe, as opposed to the light simply not having reached us yet)
Apologies if I may be confusing 2 topics here. I only follow popular science at present….