EARTH – NASA’s rover, Curiosity, has been gathering all sorts of important data and information about Mars, but the latest discovery is an especially important one.
Curiosity has detected manganese oxide in a rock it studied.
Why is that important? Because for something to oxidize, it needs water (which we already know used to exist on Mars) and oxygen.
Another way to oxidize something is with microbes, but that didn’t happen in this case.
So that leaves us with the conclusion that Mars’ atmosphere used to have oxygen in it, meaning that, at one time, Mars used to be a lot more like Earth than it is now!