The atoms that make up our world, including those in our own bodies, have a cosmic history. They were born in the hearts of stars before being scattered into the Universe during their explosive deaths.
A team of American and Canadian researchers recently shed light on the complex journey of these atoms, particularly carbon, across galaxies. These elements do not remain inert in space but are transported by massive currents, forming a galactic recycling movement essential for the formation of new stars, planets, and life.
The circumgalactic medium plays a crucial role in this process. It continuously expels and attracts materials, enabling the formation of new celestial bodies. This discovery, published in
The Astrophysical Journal Letters, opens new perspectives on the evolution of galaxies.
The researchers used the Cosmic Origins Spectrograph on the Hubble telescope to study the light from nine distant quasars. This light, passing through the circumgalactic medium of eleven star-forming galaxies, revealed the presence of carbon at impressive distances.
This study suggests that carbon, essential for life on Earth, likely spent a significant part of its existence outside our galaxy before returning to participate in the formation of our Solar System. This discovery enriches our understanding of the life cycle of galaxies and their stars.
Future research will aim to quantify the extent of other elements in the circumgalactic medium and compare their composition between active galaxies and those that have stopped forming stars. These efforts could explain why and how some galaxies become stellar deserts.
This study highlights the importance of the circumgalactic medium in the life cycle of galaxies. It shows how essential elements for life, such as carbon, are recycled across the Universe, offering a unique glimpse into our place in the cosmos.
What is the circumgalactic medium?
The circumgalactic medium is a vast region of gas and dust surrounding galaxies. It acts as a cosmic recycling system, transporting elements like carbon and oxygen between stars and intergalactic space.
This medium is essential for the formation of new stars and planets. It allows elements produced by stars to disperse throughout the Universe before being reused in the creation of new celestial bodies.
Recent studies, such as the one published in
The Astrophysical Journal Letters, show that the circumgalactic medium contains significant amounts of carbon, a key element for life. This suggests that the carbon in our bodies likely traveled through this medium before participating in the formation of Earth.
Understanding the functioning of the circumgalactic medium is crucial for studying the evolution of galaxies and the distribution of elements in the Universe.
How do stars create elements?
Stars are the cosmic factories where chemical elements are forged. Through the process of nuclear fusion, they transform hydrogen into helium, and then into heavier elements like carbon and oxygen.
When massive stars die in supernovae, they scatter these elements into space. These materials enrich the interstellar medium and contribute to the formation of new stars, planets, and eventually, life.
Carbon, essential for life on Earth, is a product of this stellar cycle. It is created in stars before being ejected into space, where it can be incorporated into new stellar systems.
This creation and dispersion of elements by stars is a fundamental process that shapes the Universe and makes possible the chemical diversity we observe today.