MYSTERIES OF THE UNIVERSE WHAT’S WRONG WITH MARS’ OXYGEN LEVELS?
Curiosity has been trundling across the surface of Mars since 2012, revealing a lot of detail about the Martian climate and the Red Planet's geology. So far the rover has proven to be invaluable in showing that Mars could have once sustained life. It has uncovered evidence of ancient persistent water flows, discovered organic carbon in rocks and found two forms of radiation that could pose potential health risks to astronauts. But its work continues to astound and confound.
In November 2019, scientists revealed the results of a study of Curiosity's data that had been gathered directly above the surface of Gale crater, the rover's landing spot. Estimated to be as old as 3.8 billion years and 154 kilometres (96 miles) in diameter, its a significant area, but on this occasion the focus has been on the detected levels of oxygen – in particular its baffling, fluctuating behaviour.
To explain, over the course of some six years, scientists have worked out that the Martian air is mainly made up of carbon dioxide, which accounts for some 95 per cent by volume. The rest
