The carbon in our bodies likely left the galaxy and returned on a cosmic conveyor belt.

Life on Earth cannot exist without carbon. However, carbon itself cannot exist without stars. Almost all elements except hydrogen and helium (including carbon, oxygen, and iron) exist only because they were forged in stellar furnaces and then ejected into space when stars died. In the ultimate act of galactic recycling, planets like ours will recycle atoms created by stars into their composition, whether it’s the iron in Earth’s core, the oxygen in the atmosphere, or the carbon in the bodies of Earthlings. formed by incorporating.

A team of scientists based in the United States and Canada recently confirmed that carbon and other star-forming atoms don’t just float around in space until they are plucked out for new uses. In galaxies like ours, new stars are still actively forming, and these atoms take circuitous journeys. They orbit their original galaxy on a huge current that spreads through intergalactic space.

These flows, known as ring-galactic media, resemble giant conveyor belts that push material out and pull it back into the galaxy’s interior, where gravity and other forces assemble these raw materials into planets, moons, asteroids, and Comets and even new stars may form.

“Think of the ring-galactic medium as a giant railroad station, with matter constantly pushing matter out and pulling it back in,” says team member Samantha Garza, a doctoral student at the University of Washington. “Heavy elements produced by stars are pushed out of their host galaxy by explosive supernova explosions, pushed into the surrounding material, and eventually pulled back into it, continuing the cycle of star and planet formation. can.”

Garza is the lead author of a paper describing these findings published Dec. 27 in The Astrophysical Journal Letters.

“The evolution of galaxies and its influence on the nature of the carbon stores available to galaxies to form new stars is intriguing,” said co-author Jessica Wark, professor and chair of astronomy at the University of Wisconsin. Ta. “The same carbon in our bodies has most likely spent a significant amount of time outside the galaxy.”

In 2011, a team of scientists confirmed the long-held theory that star-forming galaxies like ours are surrounded by a ringed galactic medium, and that this large, circulating cloud of material contains hot, oxygen-rich gas. I checked it for the first time. Garza, Werk and colleagues discovered that low-temperature materials such as carbon circulate in the circumgalactic medium of star-forming galaxies.

“We can now confirm that the perigalactic body acts like a huge reservoir of both carbon and oxygen,” Garza said. “And we think that, at least in star-forming galaxies, this material then falls back into the galaxy and continues the recycling process.”

Studying the perigalactic material could help scientists understand how this recycling process subsides, which ultimately affects all galaxies, and even our own. It will happen. One theory suggests that a slowdown or collapse of the contribution of perigalactic material to the recycling process could explain why a galaxy’s stellar population declines over time.

“If we can continue this cycle of pushing material out and pulling it back in, then theoretically we have enough fuel to continue forming stars,” Garza said.

In this study, the researchers used the Hubble Space Telescope’s Cosmic Origins Spectrometer. The spectrometer measured how light from nine distant quasars, the universe’s brightest light sources, is affected by the circumgalactic medium of 11 star-forming galaxies.

Hubble’s measurements showed that some of the light from the quasars is absorbed by a specific component of the circumgalactic material: carbon and large amounts of it. In some cases, carbon has been detected extending across intergalactic space for nearly 400,000 light-years (four times the diameter of our galaxy).

To quantify the full range of other elements that make up the circumgalactic medium and further compare how its composition differs between galaxies that are still producing large numbers of stars and galaxies where star formation has largely ceased. requires further research. These answers could reveal not only when galaxies like ours transition into stellar deserts, but also why.