Nuclear Fusion

Nuclear fusion and nuclear fission are two nuclear processes which involve enormous amounts of energy.

Hydrogen Fusion is the nuclear process were the nuclei of multiple atoms of Hydrogen combine to form the nucleus of a Helium atom. All stars fuse Hydrogen. The smallest stars, red dwarf stars, lack the mass for their cores to get dense enough to fuse Helium to higher elements. In theory, when the red dwarf star has fused all its available Hydrogen, gravity will compress it into a white dwarf.

Larger stars, including stars the mass of Sol, our sun, do get cores dense enough and hot enough to fuse Helium. Stars that begin fusing Helium are only able to do so for a duration a fraction of the time they fused Hydrogen, because Helium fusion produces much less energy than Hydrogen fusion. Similarly, the Carbon fusion period is even more brief, when a star's core can get hot and dense enough to fuse Carbon, because it produces even less energy.

With the exception of the core of an exploding Supernova, fusion stops at Iron. When a star's core can get hot and dense enough to fuse Iron the energy balance requires a large amount of energy.

The core of an exploding Supernova gets so hot and dense that elements higher than Iron get fused, as the star explodes. The Hydrogen and Helium in interstellar dust date back to the Big Bang. All other elements found in interstallar dust were blown there by a Supernova.