Primordial Nucleosynthesis

Understand

Primordial nucleosynthesis, or Big-Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background.

• There is a good global agreement over a range of nine orders of magnitude between abundances of 4He, D, 3He and 7Li deduced from observations, and calculated in primordial nucleosynthesis.
• This comparison was used to determine the baryonic density of the Universe.
• For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies.