Astronomers detected molecular oxygen 581 million light years away in galaxy Markarian 231.
This momentous “first detection of extragalactic molecular oxygen,” as it is described in a recent study in The Astrophysical Journal, has big implications for understanding the crucial role of oxygen in the evolution of planets, stars, galaxies, and life.
For the first time, astronomers have detected molecular oxygen (O2) in a galaxy outside of the Milky Way, marking a major milestone in our understanding of the universe. This discovery, led by Junzhi Wang from the Shanghai Astronomical Observatory, was made in Markarian 231, a galaxy located 581 million light years from Earth. The detection was confirmed by ground-based radio observatories, and it holds significant implications for studying planetary, stellar, and galactic evolution.
A Key Element for Life Found Far Away
Oxygen, the third most abundant element in the universe, plays a vital role in the formation of stars, galaxies, and life on Earth. Molecular oxygen, the form we breathe, consists of two oxygen atoms (O2). While it is crucial to life, molecular oxygen has been notoriously difficult to detect in space. The only previous detections of O2 within the Milky Way were in the Rho Ophiuchi cloud and the Orion Nebula, both of which were discovered using space telescopes.
However, the team led by Wang made this groundbreaking extragalactic discovery using ground-based radio telescopes. The IRAM 30-meter telescope in Spain and the NOEMA interferometer in France provided the “deep observations” needed to detect molecular oxygen in Markarian 231. Earth’s atmosphere typically blocks certain wavelengths, making it hard to detect O2 from the ground, but the redshift of the galaxy’s light helped overcome this challenge. As the light traveled across space, it stretched into longer wavelengths, making the oxygen emissions easier to detect from Earth.
Markarian 231: A Unique Galaxy
Markarian 231 is a particularly fascinating galaxy due to the presence of a quasar at its core. Quasars are highly energetic objects found in active galactic nuclei, making them some of the most powerful sources of radiation in the universe. The quasar in Markarian 231 has long captured the attention of scientists, and now its galaxy hosts the first known extragalactic source of molecular oxygen. The O2 in this galaxy is estimated to be about 100 times more abundant than in the Milky Way’s previous detections, with much of it blown into the outer regions by the quasar’s energetic outflows.
Though the oxygen in Markarian 231 is the same type humans breathe, it is not mixed with other gases such as nitrogen and carbon dioxide that make Earth’s atmosphere breathable. Nevertheless, this discovery offers a new way to study molecular gas and its behavior in galaxies affected by quasar-driven outflows.
Implications for Future Research
This finding not only adds a significant chapter to the study of oxygen in space but also offers an “ideal tool” to explore molecular outflows from quasars and active galactic nuclei (AGN). The team hopes that next-generation radio observatories, like the Next-Generation Very Large Array (ngVLA), will enable further detections of extragalactic molecular oxygen.
Future research could unlock more mysteries about the role of oxygen in planetary formation, stellar evolution, and galactic processes, bringing us closer to understanding the conditions necessary for habitability across the universe.