instead of gravity being the force of attraction between two objects, isn't it more likely that it's space itself which is affected, so in the presence of matter perhaps space becomes more dense for example, pulling away other space from around it, increasing in density (for lack of a better word) then using any residual energy to push and pull the fabric of space around it? wouldn't that explain dark gravity/matter/energy? i mean if you look at the words printed on the page of a book you assume the words are the most important part, but without the page providing a background for them to exist on there couldn't be any words at all. bend and twist that page and letters and words will twist along with the substance on which they're printed. we assume space to be nothing, to be an empty 'not there'-ness, but without this background, which has the potential to become any possible thing, there couldn't be anything at all...