Recent studies indicate that the carbon essential for life’s construction “took the scenic route” through the galaxy prior to forming our bodies here on Earth.
The researchers involved in this study found that carbon and various other elements do not merely remain idle within galaxies post-formation by stars and dispersal via supernovae.
Rather, these elements hitch a ride on massive cosmic streams known as “the circumgalactic medium” that transport them away from their galaxies into intergalactic regions, and later back in to provide the fundamental components for new stars, planets, moons, and even you.
“Consider the circumgalactic medium as a massive transit hub: It is perpetually ejecting materials outward and drawing them back in,” stated Samantha Garza, a team member and doctoral candidate at the University of Washington.
“The substantial elements synthesized by stars are expelled from their originating galaxy and into the circumgalactic medium through their cataclysmic supernovae, where they can ultimately be reabsorbed and perpetuate the cycle of star and planet genesis.”
“Next stop: the Milky Way”
The concept of a circumgalactic medium was first proposed in a study published in 2011.
Data supporting this intergalactic transport system came from the Hubble Space Telescope, revealing halos of hot, ionized oxygen spanning 500,000 light-years surrounding galaxies that are forming stars.
Previous investigations indicated that this transportation route out of galaxies is driven by galactic outflows that expel elements at high velocities. This matter is then pulled back into the galaxy by its gravitational pull.
This vast, circulating mass of material, including oxygen-enriched hot gases, was discovered to be missing from dormant galaxies that had stopped forming stars.
These recent discoveries expand upon initial studies by asserting that the circumgalactic medium is not only abundant in oxygen, but also rich in carbon, arguably the most crucial element for the emergence of life, although at lower temperatures.
This implies that the components that constitute your body are travelers from intergalactic realms that have lingered outside the confines of the Milky Way.
“We can now affirm that the circumgalactic medium functions as a massive reservoir for both carbon and oxygen,” Garza stated. “And, at least within galaxies forming stars, we propose that this material subsequently falls back into the galaxy to perpetuate the recycling process.”
Further exploration of the circumgalactic medium may assist researchers in understanding how the recycling of essential materials for new stellar entities ultimately ceases, thus halting star formation.
This could significantly contribute to understanding why certain star formations decline in galaxies, resulting in a diminishing stellar population over expansive cosmological timescales.
“The consequences for the evolution of galaxies, and for the nature of the carbon reservoir accessible to galaxies for crafting new stars, are thrilling,” remarked Jessica Werk, team member and researcher at the University of Washington. “The same carbon contained within our bodies most likely spent a substantial duration beyond the galaxy.”
The team’s findings were released on Dec. 27 in The Astrophysical Journal Letters.