Yesterday I read an article explaining that exploding stars created the calcium in our bones and teeth. It’s everywhere, that article. Stars exploding in supernovas, scattering calcium across the universe in massive quantities. It’s not really surprising, because everything is everything.
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