“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.” ― Carl Sagan, Cosmos
Scientists have come to the conclusion that the carbon, nitrogen and oxygen which make up our bodies, along with all other heavy elements, were created in stars 4.5 billion years ago. The oldest stars consisted of only hydrogen and helium. When a star exhausts its supply of hydrogen it dies in a violent explosion, a nova. A massive star creates a Supernova when it dies, throwing a cloud of dust and gas into space and dispersing the heavy elements throughout interstellar space.
Read more of my thoughts on the connection between Earth and Sky, the importance of awe and wonder, and human beings long history of understanding these truths in my recent post on the Feminism and Religion blog. And of course the Tree of Life figures into it all.