We Are Stardust

The crucial elements for life on Earth—often called the building blocks of life—are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur, abbreviated as CHNOPS. Elements are matter that cannot be broken down into simpler substances. On the periodic table, each element is distinguished by its atomic number, which describes the number of protons in the nuclei—the central, positively charged core—of its atoms. Scientists can now map the abundance of all of the significant elements found in the human body across hundreds of thousands of stars in our Milky Way Galaxy, ascertaining where in our galaxy life had the required elements to evolve. In other words, we humans really are made of stardust. As noted by the American Museum of Natural History:

“Every atom of oxygen in our lungs, of carbon in our muscles, of calcium in our bones, of iron in our blood – was created inside a star before Earth was born.

Hydrogen and helium, the lightest elements, were produced in the Big Bang.

Almost all of the other, heavier, elements were produced inside stars.”

With carbon such a hot topic (thanks to the climate change narrative), it is crucial to realize that life on Earth could not exist without it. And carbon itself could not exist without stars. In fact, almost every element besides hydrogen and helium—such as carbon, oxygen, and iron—came into being because they were created within the fiery cores of stars and then scattered across the universe when those stars expired. In a grand cycle of cosmic reuse, planets like Earth come together by weaving these star-forged atoms into their structure, from the iron deep in Earth’s core to the oxygen filling its air and the carbon shaping the forms of its inhabitants, including human Earthlings. It is truly amazing when you really think about it.

A recent news release by the University of Washington highlights how unique we humans are and yet how intrinsically connected we are to everything. Titled “The carbon in our bodies probably left the galaxy and came back on cosmic ‘conveyor belt,’ the article, based on a study published in the Astrophysical Journal of Letters, emphasizes that a team of scientists from the United States and Canada confirmed that carbon and other star-formed atoms don’t simply drift “idly through space until they are dragooned for new uses.” Instead, when looking at our Milky Way Galaxy and others like it (which are still actively forming new stars), these star-formed atoms take a circuitous journey with help from circumgalactic medium currents.

These currents are akin to enormous conveyor belts that push cosmic material out and draw it back into the galactic interior. Here, forces, including gravity, arrange these raw materials into planets, moons, comets, asteroids, and new stars. University of Washington doctoral candidate explained:

“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.”

According to the study, the same carbon in our bodies likely spent a considerable amount of time somewhere else in the universe outside of our galaxy. Wow, that thought is incredible. The researchers state that most of the carbon on Earth was likely delivered from the interstellar medium, which is the space that exists between stars in a galaxy, via the circumgalactic medium. The delivery happened long after the protoplanetary disk—a cloud of dust and gas orbiting our young sun, holding the essential components for planet formation—had formed and warmed up.

Likewise, scientists believe carbon was sequestered into solids within one million years of the sun’s birth, which means that carbon, the backbone of life on planet Earth, endured and survived an interstellar journey to our planet. Prior to this hypothesis, researchers believed that the carbon in the Earth arose from molecules that were initially present in nebular gas, which they concluded then accreted into a rocky planet when the gases were sufficiently cool enough for the molecules to precipitate.

However, researchers now know that the gas molecules that carry the carbon wouldn’t have been obtainable to form Earth, as vaporized carbon doesn’t recondense into a solid. Thus, the researchers deduced that Earth likely acquired most of its carbon directly from the interstellar medium, bypassing the vaporization process altogether. Seems like pretty solid evidence to support once and for all that God’s creations are made of stardust. Speaking of the magic that makes us who we are, Luke Sollitt, a program director in the U.S. National Science Foundation’s Division of Astronomical Sciences, shared:

“The notion that carbon might have been delivered after planetary formation is revolutionary. Studies like this, by exploring how Earth became equipped with the building blocks for life, will help us understand where we came from.”