2006/08/17 by Rennan Barkana · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1126/science.1125644
published as Science 313 (2006) 931=934 · 8 Latex pages, 3 Figures, Science, Invited Review
openalex publication_date 2006/08/17 · arxiv created 2006/08/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The earliest generation of stars, far from being a mere novelty, transformed the universe from darkness to light. The first atoms to form after the Big Bang filled the universe with atomic hydrogen and a few light elements. As gravity pulled gas clouds together, the first stars ignited and their radiation turned the surrounding atoms into ions. By looking at gas between us and distant galaxies, we know that this ionization eventually pervaded all space, so that few hydrogen atoms remain today between galaxies. Knowing exactly when and how it did so is a primary goal of cosmologists, because this would tell us when the early stars formed and in what kinds of galaxies. Although this ionization is beginning to be understood by using theoretical models and computer simulations, a new generation of telescopes is being built that will map atomic hydrogen throughout the universe.