1999/12/06 by Craig J. Hogan, Hogan, Craig J.
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9912107
to appear in the Proceedings of Inner Space/Outer Space II, the David Schramm Memorial Symposium
arxiv created 1999/12/06 · openalex publication_date 1999/12/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A fair and complete accounting of cosmic baryons now appears possible, because most of them are in states which are either directly observable or reliably constrained by indirect arguments. More than three-quarters of the baryons are probably in hot ionized gas clustering, along with galaxies and dark matter, in the cosmic web. The rest are in galaxies, roughly equally distributed between old stellar populations and star-forming disk populations; within the latter, mass is distributed about equally between stars and (mostly neutral and molecular) gas. The total amount of matter agrees with that required for concordance of cosmic light element abundances with Standard Big Bang Nucleosynthesis, a neat result inviting deeper studies of baryon evolution.