The life of a star The largest stars create nearly all of the chemical elements in the universe.
Stars produce light by nuclear fusion, which builds heavier elements out of lighter elements.
Driven by their great weight, the largest stars burn rapidly, living only ten million years, a lifespan 400 times shorter than that of the Earth. Throughout most of their short lives, big stars burn blue, but towards the end they swell and turn red. Nuclear fusion stops with the creation of iron. Without an energy source, the star collapses, triggering violent nuclear reactions that create the heavier elements such as lead, gold, and mercury. This supernova explosion is visible for millions of light years.