Big Bang nucleosynthesis

Process during the early universe

In physical cosmology, Big Bang nucleosynthesis (also known as primordial nucleosynthesis, and abbreviated as BBN) is a model for the production of light nuclei (including, but not limited to, 2H, 3He, 4He, and 7Li) during the first ~20 minutes of the evolution of the universe. The predictions of BBN rely on a combination of thermodynamic arguments and measurements of rates of nuclear reactions that are expected to be active in the early universe. Refined models tend to agree well with observations of these light element abundances.

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