We analyze the de Sitter universe using geodesic clock reference systems. Our starting point is the de Sitter universe described with a static metric form where curvature coordinates are used. This curvature metric form contains a horizon across which timelike and null trajectories cannot be followed. We show how to use new geodesic reference systems that will allow trajectories to be followed across the horizon. These geodesic reference systems are analogs to Eddington-Finkelstein and Kruskal-Novikov coordinate systems that have previously been used to analyze the Schwarzschild field. The resulting comoving synchronous coordinate systems result in metrics for the de Sitter universe that are markedly different in form from the standard Robertson-Walker isotropic metric form. This leads to questions of whether it is valid to describe the de Sitter universe with isotropic Robertson-Walker coordinates.

• Received 26 March 1982

DOI:https://doi.org/10.1103/PhysRevD.27.764