[Disclaimer: I am not a member so I could only read the first few paragraphs of this piece. Apologies in advance if I am discussing something already covered by it. AT]
What if "space" is simply very evenly distributed (and VERY low density) "mass"? It becomes what we call mass when is pulled together (topologically) and tied into an extra-diminsional, tight knot. This is done at the expense of the surrounding space/mass, further thinning it: a gravitation field.
Every type of knot has an anti-knot, such that knot and anti-knot automatically untie each other releasing the pent up space/mass which then propogates as ripples in the space/mass, i.e. light.
Food for thought??