MA Emilio Schmidt/Lothars Notes

Pressure Truncation

While it's true that space is not vacuum, in which sense and to what degree is it more accurate to ignore all mass beyond \(R_\text{max}\) (being defined via \(\rho(R_\text{max})=\rho_\text{background}\)) instead of ignoring it altogether and letting \(R_\text{max}\to\infty\)? In other words, does the mass from \(\rho_\text{background}\) contained in \(r<R_\text{max}\) play any physical role, or is rather \(\rho(R_\text{max})=\rho_\text{background}\) an "excuse" for a finite \(R_\text{max}\)?