So far there is excellent agreement with experiment. It's certainly possible that some fine details are missing. In factâ€¦ it's almost certain that some fine details are missing as quantum mechanics and GR don't play nicely together. But every time we find a new solution to the Einstein eqn we find out something profound about the Cosmos.

Answer #2 | 20/12 2013 09:18

It works and accurately predicts what we see at the scale of things larger than a quantum. But, it breaks down and gives nonsense answers at the quantum scale.====> GR is incomplete.
Quantum mechanics conjectures "gravitons" as messenger particles. this is consistent with the observed messenger particles for the other 3 fundamental forces. but, there is no proof that gravitons exist. so, we have 2 equally valid theories of what gravity is

Answer #1| 20/12 2013 06:07