http://hubblesite.org/newscen....a
This nebula is a supernova remnant (Cassiopeia A), an expanding shell of hot gas left behind when a star exploded about 340 years ago.
Every chemical element in the universe (other than hydrogen, most of the helium, and traces of lithium) had its origin in the core of a star.
As these stars die, they recycle their mass, enriched with more complex elements, into the universe, where they will eventually coalesce into another star system with planets and possibly, life.
You are made of stardust, the legacy of generations of supernovae over billions of years. The beating of your heart and the cycles of stellar life and death are intimately linked.
Billions of years hence, you will return, the atoms of your body incorporated into another star, planetary system, perhaps some sentient being. And that being will owe the carbon in its body to you, and to the stars that came before you.