We Are Stardust, Literally

A fascinating report from the Royal Astronomical Society says that roughly half of the atoms that make up the human body originated outside of our galaxy, the Milky Way, and were driven here eons ago by intergalactic winds from exploding stars. Computer simulations of stars that exploded light years away over the span of eons indicate clouds of atomic particles ejected from them were absorbed within our solar system, and ultimately within living organisms, including humans.

Northwestern University astronomer Daniel Anglés-Alcázar noted that these intergalactic winds can travel millions of light-years carrying atomic elements around the universe. While this phenomenon was known to astronomers, the scale of the extragalactic "contribution" to life on Earth was new to the astronomers:

“The surprising thing is that galactic winds contribute significantly more material than we thought. In terms of research in galaxy evolution, we’re very excited about these results. It’s a new mode of galaxy growth we’ve not considered before.”

Says another astronomer involved in the study, Claude-André Faucher-Giguère:

“What we did not anticipate, and what’s the big surprise, is that about half of the atoms that end up in Milky Way-like galaxies come from other galaxies. It gives us a sense of how we can come from very far corners of the universe...Our origins are much less local than we thought. This study gives us a sense of how things around us are connected to distant objects in the sky.” (emphasis added)

It's awe-inspiring to think that many of the atomic elements that make up the human body -- carbon, hydrogen, oxygen and nitrogen -- have come from incredibly far away from our galaxy, over many billions of years.

(picture: A pinwheel galaxy, NGC 5457, via European Space Agency)