* Astronomy

Title: Variations on Birkhoff's theorem
Authors: George F R Ellis, Rituparno Goswami

The relation between the expanding universe and local vacuum solutions, such as that for the Solar System, is crucially mediated by Birkhoff's theorem. Here we consider how that relation works, and give generalisations of Birkhoff's theorem when there are geometric and matter and perturbations. The issue of to what degree dark matter might influence the solar system emerges as a significant question.

Read more (115kb, PDF)