Evidence for oxygen? Curiosity finds a lot of manganese oxide on Mars
Manganese oxide is quite common on Earth thanks to the abundance of oxygen, but the conditions on Mars are not so good. A discovery is therefore a mystery.
On Mars, there are apparently unexpectedly high concentrations of manganese and manganese oxide in former river beds - an indication of conditions that were once favorable to life.
(Bild: NASA/JPL-Caltech/MSSS)
NASA's Curiosity rover has unexpectedly discovered highly concentrated deposits of manganese and manganese oxide in former riverbeds on Mars, suggesting that life-friendly conditions once prevailed there. This was announced by the Los Alamos National Laboratory, which provided the instrument on board the rover that discovered the deposits. Because the formation of manganese oxide is difficult under the conditions on Mars, such a discovery was not expected, explains Patrick Gasda from the large-scale research facility. On Earth, these types of deposits would form all the time because oxygen from living organisms drives the oxidation of manganese. The substance is also a source of energy for life here.
Normal on Earth, "remarkable" on Mars
Because the situation on Mars is different and it is unclear how oxygen could have been produced there, the discovery of such highly concentrated deposits of manganese oxide is "truly puzzling". Gasda therefore does not think it is inevitable to draw direct conclusions about former life on the Red Planet. The discovery points to more extensive processes in the atmosphere and in Martian waters and shows "that more work is needed to understand oxidation on Mars". At the same time, his colleague Nina Lanza says that the manganese deposits point to an environment that was surprisingly similar to those on the shores of lakes on Earth. The discovery now presented in the Journal of Geophysical Research: Planets is therefore remarkable.
The deposits were discovered with the Chemistry and Camera (ChemCam) on board Curiosity. The rover landed on Mars in 2012 and is exploring the Aeolis Mons mountain in the Gale crater. Early on, the device found traces of once life-friendly conditions there, where liquid water was probably present in lakes and rivers. Among other things, it discovered pebbles that were probably once washed along a river. We also have Curiosity to thank for indications that Mars offered suitable chemical conditions for microbes billions of years ago. However, these are only indirect indications - and there is also criticism of their interpretation: There are still no direct traces of possible living organisms.
(mho)