We are star dust..

Stars form from the gravitational collapse of interstellar gas and dust. Stars live and then die when they finally run out of fusion fuel at their centers. Upon death, stars return most of their material to the interstellar medium. However, this stellar material is laced with an abundance of heavy elements, created in the fusion reactions that took place at the center of these now dead stars. This continual cycle of

star formation,

stellar evolution,

and stellar death, serves to enrich interstellar space with `heavy' elements, such as Oxygen, Carbon, and Iron, without which, life could not form.. The next series of lectures describe the details of this very important process.