The problem of gravitational instability in an expanding universe is studied. A physically meaningful discussion is given by using as a coordinate condition the generalized de Donder gauge condition. This technique allows the general relativistic discussion to be exactly analogous to the Newtonian treatment of Bonnor (1957), and an explicit Jeans criterion may consequently be obtained. An unexpected result is found for an isothermal model universe: damping of fluctuations of any given scale occurs after sufficient time has elapsed. Approximate analytic and exact numerical solutions of the perturbation equations are presented.
- 1 - natural sciences ; 2 - physics & astronomy ; 3 - astronomy & astrophysics
- 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Space and Planetary Science
- 1 - Physical Sciences ; 2 - Physics and Astronomy ; 3 - Astronomy and Astrophysics