Proton-Proton Chain

In the Sun and other less massive stars, this chain is the primary source of heat and radiation. The proton-proton chain converts hydrogen into helium releasing energy in the form of particles and gamma rays. Hydrogen is converted into helium in a chain of reactions. The first reaction takes an average of 1 billion years to occur while the others are much shorter. One step is only 1 second long. In the Sun, there are so many hydrogen nuclei that the 1 billion year waiting period does not stop it from producing tremendous radiation.

See also: Star, Sun.