Here's ultimately how, and why, the Sun shines.

Two hydrogen nuclei, or protons-depicted here in red-fuse and form the nucleus of an isotope of hydrogen, deuterium, which has one proton and one neutron-depicted as light-blue.

And when the positively charged proton changes into a neutron, one of the protons emits a positive particle, a positron-green-and a low-energy neutrino-blue.

Next, the positively-charged positron collides with a negatively charged electron-also red to show its positive charge-and they annihilate each other in a matter-antimatter reaction, becoming pure energy at gamma ray wavelengths-bright white and purple.