HYDROGEN FUSION AT THE CENTER OF THE SUN
Also called: The Proton-Proton Chain

At the CORE of the sun, Hydrogen exists completely ionized (as a single proton, shown as a pink sphere). They are CONSTANTLY hitting each other. But about every Billion years or so, one Hydrogen atom runs into another Hydrogen atom at the EXACT same time one of the atoms decays to a NEUTRON (blue sphere), releasing a positron (purple), a neutrino (red) and energy: 1H + 1H --> 2H + e+ + V + Energy

Now we have created `heavy Hydrogen', 2H, called Deuterium. This is a nucleus with both a Proton AND a Neutron. It is STILL Hydrogen, because it has only one proton in its nucleus. There are numerous normal Hydrogen nuclei around, and almost IMMEDIATELY (within a second of time!) the Deuterium nucleus collides with another Hydrogen nucleus. They create a (light) Helium nucleus with 2 protons and 1 neutron, releasing energy in the form of a gamma-ray photon: 1H + 2H --> 3He + Ý + Energy

These Helium nuclei bounce around among the Hydrogen nuclei for about a million years before they find another of their own. When they collide, they try to merge to create a nuclei with 4 Protons and 2 Neutrons, but this is not stable. Instead, it creates the very stable Helium nuclei (2 Protons, 2 Neutrons) and the two excess Protons are thrown off as spare Hydrogen nuclei: 3He + 3He --> 4He + 1H + 1H + Energy