The unusual stability of the helium-4 nucleus is also important cosmologically: it explains the fact that in the first few minutes after the Big Bang, as the " soup " of free protons and neutrons which had initially been created in about 6: 1 ratio cooled to the point that nuclear binding was possible, almost all first compound atomic nuclei to form were helium-4 nuclei.

The unusual stability of the helium-4 nucleus is also important cosmologically.

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