Atoms, in short, are very abundant. They are also fantastically durable. Because they are so long lived, atoms really get around. Every atom you possess has almost certainly passed through several stars and been part of millions of organisms on its way to becoming you. We are each so atomically numerous and so vigorously recycled at death that a significant number of our atoms-- up to a billion for each of us, it has been suggested-- probably once belonged to Shakespeare.

Autore: Bill Bryson