Making Elements IV

When a massive star reaches the end of its life, it blasts itself apart as a supernova. But this moment of death is also a moment of creation. As the star rips itself to bits, it creates new chemical elements at a furious rate. In a matter of seconds, it manufactures most of the elements that are heavier than iron — from iodine and xenon to lead and uranium. The supernova then blasts some of these elements out into space.
Other than hydrogen and helium, which were made in the Big Bang, the elements on the lightweight end of the scale were forged by nuclear reactions in the hearts of stars. But that doesn’t work for heavier elements. Even the hottest, most massive stars can’t produce enough energy in their cores to “fuse” together lighter atoms to make anything heavier than iron and nickel.
But when the star explodes, it produces enormous amounts of energy. For a few seconds, temperatures and pressures just outside the star’s core are so extreme that a huge number of atoms fuse together