Stars, People, and Atoms
How Elements Reach Our Bodies
If you want to know where most elements originate, look at the night sky. Most of the stars and all the planets you see came from materials cooked up deep inside other stars. When those stars died, their elements were scattered into space in gas and dust clouds.
This wispy nebula (LMC N49) is the graveyard of a star that exploded as a supernova. Material in the cloud may become new stars.
We, too, are part of the cosmic recycling process. It began billions of years ago inside an ancient star. The calcium in our bones, iron in our blood, and oxygen in our lungs were all created inside that long-dead star.
Look at your hand. It is a piece of the universe. Its millions of skin cells are each made of elements from stars.
Elements are the building blocks of the universe. Atoms are the basic units of elements. Most atoms are made up of three types of particles: protons, neutrons, and electrons. Every structure in the cosmos is made of atoms from many different elements.
Each droplet of carbon shown here is a tenth of the width of a human hair and contains thousands of atoms.
Elements in Us
The human body is mostly hydrogen and oxygen, with traces of other elements (color coded to the elements table).