2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/10242Recent advances in observational cosmology are changing the way we view the nature of time. In general relativity, the freedom in choosing a time hypersurface has hampered the implementation of the theory. Fortunately, Hamilton-Jacobi theory enables one to describe all time hypersurfaces on an equal footing. Using an expansion in powers of the spatial curvature, one may solve for the wavefunctional in a semiclassical approximation. In this way, one may readily compare predictions of various inflation models with observations of microwave background anisotropies and galaxy clustering.19 pages, self-unpacking, uuencoded, gz-compressed postscript file, in Proceedings of the International School of Astrophysics, ``D. Chalonge'', Erice, Italy, September 8-19, 1995, Three additional figuresAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext