Ok folks here's my two cents on the subject . . . I see gravity commonly referred to as a force but it really better thought of as a "weak" effect of attraction between masses. All masses, visible or not, are effecting all others simultaneously. The problem is that gravity, being "weak" is effected greatly by the distance between masses; it becomes an "observable" effect in the local vicinity of the mass.

There are still weird things we don't understand about the whole mess. For example, our galaxy Milky Way is in a cluster of galaxies called the Virgo cluster which includes, I believe M81, the Andromeda galaxy and maybe 4 other galaxies in the same general vicinity of space. As with all other observable matter, the whole Virgo cluster is hurtling thru space away from the "center" of the Universe. The issue is that the Andromeda galaxy has been observed to be accelerating towards Milky Way. A look towards the acceleration vector, for the source of this effect, is empty space. Impossible. So the scientists have placed a massive object where none can be seen called "the Big Kahuna". Meanwhile M81 will collide with Milky Way in some odd billion years on it's way to "the Big Kahuna". I don't know about you, but I am really perplexed by this observation.

Something to think about: how could a black hole prevent light from escaping if gravity was constrained to the speed of light? Must it not be capable of imparting a vector acceleration greater than the speed of light (simultaneous qualifies here) opposite to the photon's vector of travel?