Some time ago, in some thread here (I don’t remember which one), someone wondered what the speed of gravity is. That was a challenging thought, as I never asked myself that question and I enjoyed thinking about that … it simply felt like a good exercise for the brain. From my own thoughts, I concluded that gravity propagation speed has to be infinite. To cut the story short – if a distant object disappears (explodes, for example), then the lack (disappearance) of gravitational pull can only be detected instantaneously everywhere, no matter how far from that (former) object. If there would be a speed, one would have to consider that gravitational effect can exist now from an object that existed only in the past, the same way that the light from an already extinguished star still reaches the observer’s eye even years after that star does not emit light anymore – gravity does not work the same way, although in calculations and observations it is often associated and assimilated with a “wave” (it is indeed hard to imagine a wave propagating at an infinite speed).
Another thing that I often heard in all sorts of documentaries, is that many scientists scratch their heads about the “missing” mass in our universe, as the calculations having background radiation as a base suggest that there should be a lot more mass than it actually is. Could it be a better approach to have as a base the sum of all the gravitational pull(s) rather than background radiation ?!?! – one may find out that it all adds up and that there is actually no mass missing. I genuinely believe all the mass that is reported “missing” is in fact swallowed in those numerous black holes that are out there and it still acts with gravitational pull, even from within those black holes … which brings me back on the answer to the initial question – gravity DOES escape a black hole … in fact I think it is ONLY gravity that can escape a black hole -–mass can not, space can not, time can not. Every black hole has its own space-time, completely different from ours.
Those were my modest thoughts on this subject, I hope I did not bother anyone by bringing them out.