# Is the curvature of space around mass independent of gravity?

Is the curvature of space caused by the local density of the energy in that area?Could gravity be a separate phenomenon only arising from the curvature of space? For instance if the density of energy in a particular area cause that area of space to ”curve” but the effect that we understand as gravity, (causing anything with mass to be attracted to each other) is only arising as a consequence of that space being curved. I guess it seems to me that things other than mass can cause the curvature of space (electromagnetic fields, an enormously high density of photons in a small area or at least I think so, but I'm not sure about the photons, and if a black hole rotating causes frame dragging (which I'm assuming means the surrounding physical metric of space is probably some mechanism, or thought experiment where you could ball up space tight enough to become a black hole even without any matter in it. I guess it's another question I Could ask.

-

As understood by Einstein's general theory of relativity completed in 1915-16, gravity is indeed a manifestation of (nothing else than) the curvature of space and I have some doubts about your implicit claim that you have made this discovery "independently" of Einstein. According to the precise equations of general relativity, the so-called Einstein's equations $$G_{\mu\nu} = \frac{8\pi G}{c^2} T_{\mu\nu},$$ what influences the curvature of spacetime is the stress-energy tensor that knows about the density of energy and momentum and the flux of energy and momentum. Terms like "flux of momentum" may sound obscure but they are described by well-defined mathematical formulae. In particular, "flux of momentum" is nothing else than the component of pressure. So pressure also influences the curvature of spacetime – and therefore the gravitational field and the behavior of objects in this field – according to general relativity.

On the other hand, it is irrelevant for the curvature and gravity whether the same stress energy tensor – the density of mass, energy, momentum, and components of pressure and stress – are achieved by the electromagnetic field, one material, or another material. However, it's still impossible to "create" curvature of space without any material (or energetic) carrier. The equations explicitly show that the Ricci tensor is zero if there's no energy/momentum density in the space. So one can't create a "black hole out of nothing".

Nevertheless, black holes may suck all the material and make the spacetime around Ricci-flat; the Ricci (or Einstein) tensor is equal to zero almost everywhere in the space. This Ricci-flatness is still importantly violated at the black hole singularity which is the reason why the black holes still carry a nonzero mass/energy.

The question is getting increasingly impenetrable as one continues to read it so what you exactly wanted to do with the frame-dragging effect remained unknown to me (and I guess that not only me). Frame-dragging is a particular new gravitational effect that occurs in the gravitational field induced by rotating bodies.

-
I can barely discover how to spell many of the words you used, I certainly don't think I'm discovering anything new! LOL much to my regret I seem to be unable to learn the language of mathematics But I am very curious and I'm simply trying to visualize how things work, I'm sure that will leave me unable to comprehend some of the more counterintuitive concepts. But I enjoy trying to learn! Thank you very much for taking the time to trying to help me understand. –  Todd Burkett Jan 25 '12 at 9:44
@ToddBurkett The ability to visualize is not necessirely a measure for understanding. –  Revo Jan 25 '12 at 10:49