Besides hydrogen and helium, oxygen is the most common element in the cosmos. Naturally, experts believed that such an abundant item would be fairly easy to spot, but all attempts to detect it outside of our own galaxy had turned up disappointing results. However, astronomers have finally found signs of breathable oxygen in a galaxy that is half a billion light-years away. According to the study published in The Astrophysical Journal, the discovery of the extragalactic molecular oxygen could help us understand the crucial role oxygen plays in the evolution of galaxies, stars, planets, and, of course, life.

Researchers at the Shanghai Astronomical Observatory found signatures of molecular oxygen when analyzing light waves that reached the Earth from a galaxy called “Markarian 231,” which is located 581 million light-years away.

Molecular oxygen, or O₂, is the common free form of this element. In chemistry, free elements are those that have not chemically bonded or combined with other elements. Humans and many other organisms need this form of oxygen to breathe. Despite being ubiquitous and significant to habitability, molecular oxygen is hard to detect in the wider universe. Now, a team of astronomers, led by Junzhi Wang of Shanghai Astronomical Observatory, has discovered signs of molecular oxygen in a galaxy named Markarian 231. The Type-1 Seyfert galaxy is located in the constellation Ursa Major, approximately 581 million light-years away.

The team used ground-based radio telescopes, namely the IRAM 30m millimeter radio telescope in Spain along with the NOEMA (NOrthern Extended Millimeter Array) interferometer in France, to conduct “deep observations.” They analyzed light waves that reached the Earth from Markarian 231 and found radiation at wavelengths of 2.52 millimeters, a signature that indicates the presence of breathable oxygen. Getting accurate readings from lightwave analysis has proven difficult because a significant portion of the wavelengths that reach us from distant galaxies gets absorbed by Earth’s atmosphere, and ground-based telescopes struggle to pinpoint oxygen molecules.

So far, molecular oxygen has been detected in two locations within the Milky Way. However, Wang and his team are the first to detect O₂ in a different galaxy.

Due to the complications mentioned above, finding molecular oxygen in the larger cosmos has not been easy. In the last 20 years, scientists have found two locations within our own galaxy where molecular oxygen is present. One is the Orion Nebula, which is located 1,344 light-years away from Earth, and the other is the Rho Ophiuchi Cloud, which is located around 350 light-years away. In both instances, space satellites did not have to face an obstructive atmosphere.

However, this is the first time that a group of astronomers has found traces of molecular oxygen in a different galaxy. It has led many people to question how they were able to detect oxygen using ground-based equipment. It was possible partly because light waves from Markarian 231 were redshifted (turned into longer wavelengths) as they traveled across the vast expanse of space. Consequently, the Earth’s atmosphere could not block or absorb these waves.

Markarian 231 has long been an enigma in the scientific community, and the latest discovery has made experts more curious. But can humans travel there and breathe? Experts say, no.

Markarian 231 was first discovered in 1969, and since then, it has made scientists all over the world curious. One of the many key features of this enigmatic galaxy is that it is home to the closest known quasar to Earth. One of the most powerful and radiant objects in the cosmos, quasars are a type of AGN or active galactic nuclei, which are found at the center of a galaxy.

The discovery of oxygen has made many people question whether humans could travel there and breathe freely. We cannot, simply because the oxygen in Earth’s atmosphere is mixed with the right amounts of carbon dioxide, nitrogen, methane, and other molecules, which makes it breathable. The oxygen found in Markarian 231 does not have the same makeup.

(Sources: 1, 2 ,3, 4)