Note that in GR defining energy consistently is tough. Doing it so it is globally conserved is even harder. We only really have local conservation, and the changing background of GR in cosmology is in some sense effectively the same thing as changing physical law.
Note that in GR defining energy consistently is tough. Doing it so it is globally conserved is even harder. We only really have local conservation, and the changing background of GR in cosmology is in some sense effectively the same thing as changing physical law.