It’s easy to forget that most of what makes you “you” is actually billions of years older than you think, considering that the human body is composed of 7 octillion atoms, the vast majority of which are hydrogen atoms that were formed in the big bang some 13.8 billion years ago.
Most of the remaining atoms were made when stars merged or exploded billions of years after the big bang, while a small number of atoms were made due to cosmic ray fission.
Astronomer Carl Sagan famously described the situation in an episode of Cosmos, “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.”
And now, to give us an even better idea of where specifically our atoms originate from, Jennifer A. Johnson, an astronomer at the Ohio State University, composed the handy periodic table seen below and featured on her blog with the Sloan Digital Sky Survey.