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.
BigM16