[bakedbeing]

Only if gravity moves at the same speed as light, right? It sounds like we've been observing energy emissions (light) rather than directly observing it's gravitational impact on us.

[ars]

Gravity has to move at the same speed as light. If it didn't it would cause time paradoxes.

[bakedbeing]

Ah of course, a theoretical graviton being a massless particle. That's what I get for not having a wee Google first.

[awj]

My understanding (note: I am not a physicist, this is not a physics lesson) agrees with ars, gravity has to move at the same speed as light.

In either case, the energy emissions potentially are enough, if they're directed at us and strong enough.