Made of Star Stuff
The calcium in your bones and the iron in your blood were made inside stars that died before the Sun was born.
What’s going on
The Big Bang made almost nothing but hydrogen and helium. Heavier elements came later: stars fuse light atoms into heavier ones such as carbon and oxygen, and exploding stars make and scatter many more, including much of the calcium and iron in us. Those ingredients mixed into the cloud that formed the Sun and Earth about 4.6 billion years ago, and in time became part of every living thing.
Myth
Everything in your body was made in stars.
Fact
The hydrogen in every water molecule inside you dates back to the Big Bang.
Learn more
NASA Chandra X-ray Center, “Chemistry of the Universe” (chandra.si.edu/chemistry).
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