2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/148469An introduction to models of open universes originating from bubbles, including a summary of recent theoretical results for the power spectrum. To appear in the proceedings of the XXXIth Moriond meeting, "Microwave Background Anisotropies."LaTeX file, uses epsf.tex, 3 figures, 8 pages, minor wording changes to clarify discussion of coordinate systemsAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext