Observational tests of antimatter cosmologies.
Abstract
The problem of the amount and astrophysical role of antimatter in the Universe is investigated. The main questions considered include whether the Universe must be symmetric and whether it is symmetric. Direct and indirect objective and subjective evidence concerning matter-antimatter symmetry is presented, difficulties faced by a symmetric big-bang cosmology are examined, and the symmetric big-bang model proposed by Omnes (1969) is studied in detail. Matter-antimatter separation, remixing, annihilation, and nucleosynthesis are analyzed in the framework of this model. Symmetric steady-state models are evaluated, particularly the model proposed by Alfven and Klein (1962). It is suggested that the Universe must not necessarily be symmetric, and it is noted that the observational data provide no evidence for the presence of any antimatter in the Universe. Significant amounts of antimatter are shown to be excluded from the Local Group, clusters of galaxies, and the intergalactic medium by gamma-ray studies. It is concluded that antimatter cannot play a significant astrophysical role at present, although the early evolution of a symmetric Universe must have been influenced by the presence of antimatter, and that the Universe is not symmetric.
- Publication:
-
Annual Review of Astronomy and Astrophysics
- Pub Date:
- 1976
- DOI:
- 10.1146/annurev.aa.14.090176.002011
- Bibcode:
- 1976ARA&A..14..339S
- Keywords:
-
- Antimatter;
- Astronomical Models;
- Big Bang Cosmology;
- Universe;
- Annihilation Reactions;
- Galactic Clusters;
- Interstellar Matter;
- Matter (Physics);
- Nuclear Fusion;
- Symmetry;
- Astrophysics