The Beginning of the Universe

Fraser Cain and Pamela L. Gay explore what cosmology can establish about the universe’s earliest history and where knowledge remains limited. The discussion covers inflation, the separation of forces, the emergence of particles and nuclei, and density fluctuations that seed later structure. Recombination and the cosmic microwave background lead into the dark ages, the first stars and reionization, with observations including JWST helping test models of the early universe. Pamela Gay is a senior scientist at the Planetary Science Institute. This Astronomy Cast episode was published on 14 September 2026; its publisher feed labels it The Beginning and End of Everything, Part 1. The original duration is 39 minutes 27 seconds.