FRW Universe Models in Conformally Flat Spacetime Coordinates. III: Universe models with positive spatial curvature

摘要

We deduce general expressions for the line element of universe models withpositive spatial curvature described by conformally flat spacetime coordinates.Models with dust, radiation and vacuum energy are exhibited. Discussing theexistence of particle horizons we show that there is continual annihilation ofspace, matter and energy in a dust and radiation dominated universe, andcontinual creation in a LIVE domined universe when conformal time is used inFriedmann-Robertson-Walker models with positive spatial curvature. A generalprocedure is given for finding coordinates to be used in Penrose diagrams. Wealso calculate the age and the redshift of some universe models using conformaltime.