We are all made of stardust. It sounds like a line from a poem, but there is some solid science behind this statement: almost every element on Earth was formed at the heart of a star. After the Big Bang, tiny particles bound together to form hydrogen and helium. The human body is about 60% water and hydrogen accounts for 11% of that water mass.
The carbon, nitrogen and oxygen atoms in our bodies, as well as atoms of all other heavy elements, were created in previous generations of stars over 4.5 billion years ago. Humans and every other animal as well as most of the matter on Earth contain these elements, we are literally made of star stuff, said Chris Impey, professor of astronomy at the University of Arizona.
“All organic matter containing carbon was produced originally in stars,” Impey told Life’s Little Mysteries. “The universe was originally hydrogen and helium, the carbon was made subsequently, over billions of years.”
Every element in the periodic table aside from hydrogen is essentially stardust, If we know how many hydrogen atoms are in our body, then we can say that the rest is stardust. Our body is composed of roughly 7×1027 atoms.
Now it turns out that of those billion billion billion atoms, 4.2×1027 of them are hydrogen. This leaves 2.8×1027 atoms of stardust. Thus the amount of stardust atoms in our body is 40%.