Cosmic epoch · Cosmology
Big Bang Nucleosynthesis
Cosmology & UniverseEstablished Science
Definition
The production of the light elements — hydrogen, helium, and traces of lithium — in the first few minutes of the Universe.
Scientific overview
For about three minutes the Universe was hot and dense enough for nuclear fusion, forging roughly 75% hydrogen and 25% helium by mass, plus a trace of lithium and deuterium. The predicted abundances match observations remarkably well, providing one of the strongest confirmations of the hot Big Bang.
Evidence
- Measured primordial abundances of helium-4 and deuterium match theory to high precision
Open questions
- Why is the observed primordial lithium abundance lower than predicted?
Rests on
Knowledge connections
- Predicted byThe Big Bang
- Depends onThe Big Bang
- Part of modelThe Lambda-CDM Model
- Preceded byCosmic Inflation
- Followed byRecombination
- Associated withAdvanced Burning Stages
- Associated withStellar Metallicity
- Associated withThe Cosmic Neutrino Background
Sources & references
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.