The idea that we all come from ‘cosmic dust’ in the universe and our bodies will eventually break down and go back into the Earth (and eventually, further out into the universe) can be both scary and comforting.

A study that was published in the Astrophysical Journal Letters shows that not only do the elements that make up our bodies (and everything else) come together from the surrounding environment, but that they almost certainly traveled great distances to get here. These atoms likely traveled outside of our own galaxy for millions of years before being sucked in to form Earth and all of us humans.

Other than helium and hydrogen, all elements are formed in stars. The elements are then scattered out great distances when the star dies in a supernovae or other major event. According to the study, those elements travel much further than most people believed, traveling through what is called the circumgalactic medium.

Samantha Garza is a doctoral candidate at the University of Washington and the lead author on the study. In a statement, she said:

“Think of the circumgalactic medium as a giant train station: It is constantly pushing material out and pulling it back in. The heavy elements that stars make get pushed out of their host galaxy and into the circumgalactic medium through their explosive supernovae deaths, where they can eventually get pulled back in and continue the cycle of star and planet formation.”

The elements may travel back and forth throughout the medium for millions of years before eventually gravity takes hold enough to solidify them into stars, planets, moons, and in some lucky cases, humans.

Professor Jessica Werk is a co-author of the study and added:

“The implications for galaxy evolution, and for the nature of the reservoir of carbon available to galaxies for forming new stars, are exciting. The same carbon in our bodies most likely spent a significant amount of time outside of the galaxy!”

The concept of a circumgalactic medium has been talked about for a long time, but its actual existence has only been considered confirmed since 2011.

This study helps to explain how there are enough materials available in different areas to continue to create new stars even after billions of years. Garza explained:

“If you can keep the cycle going – pushing material out and pulling it back in – then theoretically you have enough fuel to keep star formation going.”

The fact that the atoms in our bodies likely traveled unphathomable distances for billions of years before finding their way here is astounding.

I guess we are all very well-traveled.

If you thought that was interesting, you might like to read a story that reveals Earth’s priciest precious metal isn’t gold or platinum and costs over $10,000 an ounce!