Breakthrough discovery reveals oxygen formation without life in CO2-rich atmospheres

Scientists have uncovered a new pathway for oxygen production in carbon dioxide-rich atmospheres, demonstrating that molecular oxygen (O2) can form without biological activity.

This finding challenges conventional methods for detecting extraterrestrial life by suggesting that oxygen in planetary atmospheres might not always indicate the presence of living organisms.

Researchers Shan Xi Tian and Jie Hu from the University of Science and Technology of China have identified a chemical reaction in which helium ions (He+) interact with carbon dioxide (CO2) to produce molecular oxygen. Using advanced experimental tools like time-of-flight mass spectrometry and ion velocity mapping, they replicated this reaction in controlled conditions to uncover how oxygen could arise through non-biological processes.

The study highlights the potential for this reaction to occur in the upper atmosphere of Mars, where CO2 dominates, and helium ions are generated by solar winds. While the Martian ionosphere contains ions like O+, O2+, and CO2+, direct evidence of molecular oxygen forming via this newly discovered mechanism remains elusive.

Dr. David Benoit, a Senior Lecturer in Molecular Physics and Astrochemistry at the University of Hull, emphasised the importance of this discovery for planetary science. He noted that it expands the understanding of oxygen formation in planetary atmospheres and could influence astrochemical models used to predict conditions on exoplanets.

The simultaneous presence of CO2, helium, and oxygen in an atmosphere could indicate an abiotic origin for oxygen, altering how scientists evaluate the potential for life on distant worlds.

By revealing that oxygen can form independently of biological processes, this breakthrough reshapes the parameters for identifying life beyond Earth, opening new avenues for exploring the origins of life and planetary evolution.