Oxygen is not always synonymous with life

The relationship between oxygen and the emergence of life has just been deconstructed by a European study that shows that the presence of oxygen is not always accompanied by the presence of life in the same place. Photosynthetic organisms are generally at the origin of the emergence of life since the mechanism by which they absorb carbon dioxide and the energy of the sun’s rays to release oxygen, allows life to develop.

At the scale of the universe, scientists have thus privileged the search for traces of oxygen to define if exoplanets could be habitable and could host life. According to a study by Swedish, French and British researchers published in the journal Science Advances on August 19, 2022, finding oxygen does not always mean the presence of life. Researchers have discovered a source of oxygen that is not related to the presence of life and is characterized as abiotic oxygen, not from a living organism but from sulfur dioxide.

High energy radiation from a star can ionize sulfur dioxide molecules, which are very present on the surface of many celestial bodies with volcanic activity. This molecule must then reorganize itself into a double positive charge system, causing the partition of the atoms of sulfur dioxide with the atoms of oxygen, which will move away from those of sulfur. This phenomenon, called roaming, can lead to the fragmentation of two atoms into new compounds and give rise to oxygen.

Scientists believe that this process may explain why some celestial bodies contain oxygen but show no evidence of life. This discovery can also enrich the knowledge on the appearance of oxygen on Earth, as sulfur dioxide could have released a certain amount of oxygen before the beginning of the great oxygenation of the Earth’s atmosphere.

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