Geodesics in the isotropic universe
The analytic form of the geodesics in the Robertson-Walker metric is found. All kinds of geodesics (timelike, null and spacelike) are examined, for all possible Friedmann models (closed, flat and open). Use is made of the solutions of the Einstein equations for the above models and for the equations of state corresponding to dust and radiation. The cosmological constant is taken equal to zero.
scientific article; zbMATH DE number 4094327