4 ms·

Well, in classical GR, which is still our best and most accurate theory of gravity, gravity is only an apparent force and thus isn't (or can't be) mediated by a

• gpderetta 8y ago
  disclaimer: IANAP. as far as I understand, the space-time curvature is just an interpretation of the math. Another perfectly acceptable interpretation is as a relativistic classical field that couples with the stress-energy tensor field (thus, indirectly, with any other field). In fact I think it is possible to come up with a space-time curvature interpretation of the EM field, for a toy universe where everything has a EM charge. Now, given that the gravitational field couples with other fundamental fields and those are quantized, the gravitational field must necessarily also be quantized. The math straight forward quantization works fine for low energies, thus the spin-2 boson described elsethread. The issue is that at low energy, the gravitational effects are so small that it is impossible to come up with an experiment that would detect the difference between a classical field and a quantized field. At high energy the straightforward derivation breaks down because of infinities (other quantum fields had similar issues, but the math tricks used to resolve them do not work with the gravitational field). There are multiple theories (string theory, loop gravity, etc) that try to resolve this problems, but the experimental apparatus required to distinguish between them are colossal (as in particle accelerators with radii measured in AU).