 In terms of Noether's theorem, the ADM energy, momentum, and mass are defined by the asymptotic symmetries at spatial infinity, and the Bondi energy, momentum, and mass are defined by the asymptotic symmetries at null infinity.Note that mass is computed as the length of the energy–momentum four vector, which can be thought of as the energy and momentum of the system "at infinity".In the Newtonian limit, for quasi-static systems in nearly flat space-times, one can approximate the total energy of the system by adding together the non-gravitational components of the energy of the system and then subtracting the "Newtonian" gravitational binding energy.