triple-alpha process

The triple-alpha process is how stars create carbon, an essential element for life. Inside a star, high temperatures and pressures cause helium nuclei (two protons and two neutrons) to collide and fuse. First, two helium nuclei form a unstable beryllium-8 isotope. If another helium nucleus collides with this beryllium quickly enough, it creates a stable carbon-12 nucleus. This process occurs in the dense, hot core of a star and is a key step in the nuclear fusion reactions that power stars and produce the elements necessary for life.