Many atoms in your body are nearly as old as the universe itself. When you breathe, for example, only some of the atoms that you inhale are exhaled in your next breath. The remaining atoms are taken into your body to become part of you, and they later leave your body by various means. You don't "own" the atoms that make up your body; you borrow them. We all share from the same atom pool because atoms forever travel around, within, and among us. Atoms cycle from person to person as we breathe and as our sweat is evaporated. We recycle atoms on a grand scale. The origin of the lightest atoms goes back to the origin of the universe, and most heavier atoms are older than the Sun and Earth. There are atoms in your body that have existed since the first moments of time, recycling throughout the universe among limitless forms, both nonliving and living. You're the present caretaker of the atoms in your body. There will be many who will follow you.