You might expect two alphas to make 8Be and then another alpha to make 12C, but 8Be is unstable on a very short timescale 10^-16 seconds. Amazingly, 12C has a

You might expect two alphas to make 8Be and then another alpha to make 12C, but 8Be is unstable on a very short timescale 10^-16 seconds. Amazingly, 12C has a resonance called the Hoyle State that allows a triple alpha to 12C process. The Hoyle State is basically the only quantitative PREdiction of the anthropic principle. https://en.wikipedia.org/wiki/Carbon-12 https://en.wikipedia.org/wiki/Carbon-12