All the other forces in nature have opposites – so what makes gravity different?
I believe gravity does have an opposing force, that is, a celestial object of large enough size pushing on itself. All of the mass in the Earth pushes against itself creating a significant amount of energy. This energy, at some point, inverts into a pull (gravity as we know it) that extends about the North/South poles of the Earth as an arc. Look at the attached JPG to see what I think is happening. You can picture the gravitational field in much the same way as a magnetic field, even though the two are completely unrelated.
When a star explodes, the gravitational attraction severely overcomes the expansion of gasses caused by heat, thus gravity feeds(?) off the explosion and creates a black hole. If a sun is made up of gas, then a black hole is made up of light. A black hole and a star both create a gravitation field, and the gravitational field is dependent on the amount of energy contained within the celestial object.
Possibly then, could dark matter just be matter so dense that it consumes light?
I'm not a physicist, I have no degrees in anything that makes what I'm saying true or correct, but what I do have is imagination and creativity. The same imagination that Einstein had when he theorized GR. It is with this imagination I can think outside the box of what we know, what we don't know, and what is or is not possible. I bring to you today, this theory of mine, in hopes that I can discuss it with people who know what they are talking about, and also feel the same passion towards advancing science that I do.