[19]they will fuse releasing energy. Georgia State University: Proton-Proton Fusion fusion process Proton-proton fusion cycle pp (proto-proton). proton-proton fusion http://hyperphysics.phy-astr.gsu.edu/hbase/astro/procyc.html proton-proton cycle HyperPhysics: Proton-Proton Fusion http://hyperphysics.phy-astr.gsu.edu/hbase/astro/procyc.html http://hyperphysics.phy-astr.gsu.edu/hbase/astro/procyc.html HyperPhysics: Proton-Proton Fusion [19]they will fuse releasing energy. HyperPhysics: Proton-Proton Fusion http://hyperphysics.phy-astr.gsu.edu/hbase/astro/procyc.html http://hyperphysics.phy-astr.gsu.edu/hbase/astro/procyc.html