# Div G_ab = 0

## Main Question or Discussion Point

What physical meaning can be ascribed to the non-divergence of the Einstein tensor? I find it counterintuitive since I associate divergence with field sources (like the electrical field of a proton) and obviously a gravitational field has a source. Is there a parallel with Newton's formulation of gravity that might be instructive?

Last edited:

## Answers and Replies

Related Special and General Relativity News on Phys.org
What physical meaning can be ascribed to the non-divergence of the Einstein tensor? I find it counterintuitive since I associate divergence with field sources (like the electrical field of a proton) and obviously a gravitational field has a source. Is there a parallel with Newton's formulation of gravity that might be instructive?
Since the Einstein tensor is proportional to the stress-energy-momentum tensor, T it means that energy and momentum is conserved since div T = 0. This holds true even when the cosmological constant is non-zero.

Pete

haushofer
So Einstein created the stress-energy tensor first, then made $$G_{ab}$$ to match it?