NASA's Curiosity rover has been exploring the Gale Crater on Mars since 2012, and in that time has come up with some astounding discoveries that suggest the Red Planet was somewhat Earth-like in its earlier times.
The rover has come through again, this time detecting significant amounts of manganese oxides inside of mineral veins.
Said researcher Nina Lanza of New Mexico's Los Alamos National Laboratory, "The only ways on Earth that we know how to make these manganese materials involve atmospheric oxygen or microbes. Now we're seeing manganese oxides on Mars, and we're wondering how the heck these could have formed?"
She further notes, "One potential way that oxygen could have gotten into the Martian atmosphere is from the breakdown of water when Mars was losing its magnetic field. It's thought that at this time in Mars' history, water was much more abundant."
A combination of that weakened magnetic field, ionizing radiation, and low gravity may have both split the water into its separate elements and rendered the Red Planet incapable of holding onto its hydrogen ions, leaving only the oxygen to linger.
Lanza does admit, "It's hard to confirm whether this scenario for Martian atmospheric oxygen actually occurred."
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