The first direct evidence that oxygen was present on Mars has just been made public, a historic announcement in the investigation of the red planet.
A red planet that is called that because its surface is full of iron oxide, which gives it that characteristic reddish color. This is not something new, much less, but what Curiosity has discovered goes much further.
The Institute for Research in Astrophysics and Planetology in Toulouse, France, has been commissioned to announce to the world that they have discovered that 3% of the rocks examined in the Gale sump contain manganese oxide in addition to iron oxide.
On Mars there was oxygen, it is already a truth
Why is it important to find a specific type of oxide? Well, because not all oxide is formed equal; iron rusts easily, but For manganese to do the same, it is necessary that certain conditions exist: an abundance of water, and a highly oxidizing atmosphere.
In other words, manganese oxide had to form in the past, when Mars had plenty of water and there was a lot of oxygen in its atmosphere. (Although they have not yet been able to discern when it occurred). In fact, this discovery points to the fact that there was much more oxygen than originally thought.
To obtain this information, the Curiosity rover has used the ChemCam, an instrument that fires a laser at the rocks and analyzes the resulting dust cloud. This result can be considered historical, since it confirms theories that until now had only circumstantial evidence on which to base themselves; instead, this is the most direct and definitive proof that there were indeed high concentrations of oxygen on Mars.
Does that mean that in the past Mars was a perfect crucible for life, thanks to the presence of water and oxygen? Not so fast. Having high concentrations of oxygen is actually a bad thing for primal life, since it can oxidize and break down biological molecules. That there are high concentrations of oxygen on Earth is a consequence of life, not the other way around.
Today, the atmosphere of Mars is 95% carbon dioxide, and contains only trace amounts of oxygen. With this discovery, we are closer to knowing how Mars became the desert planet that it is now.