Astronomers have spotted molecular oxygen in a galaxy far far away, marking the first time that this important element has ever been detected outside of the Milky Way.
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.
Oxygen is the third most abundant element in the universe, after hydrogen and helium, and is one of the key ingredients for life here on Earth. Molecular oxygen is the most common free form of the element and consists of two oxygen atoms with the designation O2. It is the version of the gas that we humans, among many other organisms, need to breathe in order to live.
Yet despite its ubiquity and significance to habitability, scientists have struggled for decades to detect molecular oxygen in the wider cosmos.
Now, a team led by Junzhi Wang, an astronomer at the Shanghai Astronomical Observatory, reports the discovery of molecular oxygen in a dazzling galaxy called Markarian 231, located 581 million light years from the Milky Way.
The researchers were able to make this detection with ground-based radio observatories. “Deep observations” from the IRAM 30-meter telescope in Spain and the NOEMA interferometer in France revealed molecular oxygen emission “in an external galaxy for the first time,” Wang and his co-authors wrote.