The new discovery of the Curiosity rover provides evidence that once ancient Mars and its atmosphere were indeed very similar to Earth. The Autonomous Martian Laboratory has found traces indicating that the atmosphere of ancient Mars contained an impressive supply of oxygen.
Using the ChemCam scientific instrument on the back of the Curiosity, scientists at Los Alamos National Laboratory have discovered high levels of manganese dioxide in Martian rocks. Curiosity made its discovery in mineral-rich fissures located in a place called Kimberley, which is located in Gale Crater. The presence of this chemical element indicates that Mars once contained high levels of free oxygen. In addition, this find suggests that the climate of the Red Planet was once much warmer, and on its surface, perhaps, there were even whole lakes of liquid water. In other words, in terms of chemical composition, this planet used to be very similar to Earth.
And here is the find itself - manganese
Image: MSSS / JPL / NASA
"The only options for making these manganese compounds here on Earth involve recruiting atmospheric oxygen or microbes," notes lead author Nina Lanza.
"Now we are observing residual manganese dioxide reserves on Mars and we are wondering quite a fair question - how did it appear there?"
It is very unlikely that microbes are the source of this manganese on Mars, but the assumption that it appeared due to the presence of free oxygen on the Red Planet is quite true. The researchers say that materials containing high levels of manganese, such as those found on Mars, cannot form without sufficient amounts of liquid water and oxygen.
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This prompts scientists to another question: where did all this oxygen come from and where did it go? Lanza's team suggests that oxygen may have formed from the Martian water after the Red Planet's magnetic field began to collapse. Without a magnetic field, the planet could not defend itself against ionizing radiation, and the molecules contained in the water began to split into hydrogen and oxygen. Due to the relatively low gravity of Mars, the planet was unable to hold onto the lighter hydrogen atoms, but the heavier oxygen atoms remained in place.
Over time, this oxygen accumulated in the rocks and created a reddish dust that now covers the planet's surface. It should be noted that the creation of iron oxides does not require large reserves of oxygen, but for the creation of manganese dioxide it is required. This, in turn, means that Mars once contained large volumes of this element.
The results are quite interesting. They may mean that many billions of years ago, Mars could have been inhabited. It may have had simple microbial life (although we have not yet found direct evidence of this). The oxygen needed to sustain life, at least here on Earth, is used for cellular respiration and other biological processes. Many important classes of organic matter (including proteins, nucleic acids, carbohydrates, and fats) in living organisms contain oxygen. There is, of course, the possibility that some exotic species could exist on Mars that could do without oxygen, but oxygen is vital for the vast majority of living organisms on Earth.
In conclusion, it should be noted that not only "Curiosity" found traces of magnesium on Mars. Another rover, Opportunity, thousands of kilometers from Curiosity, recently also found high levels of manganese dioxide in Martian sediments. In other words, the presence of this mineral elsewhere increases the likelihood of scientists guessing about a wetter, warmer and more breathable Mars.
Next, the researchers plan to compare the manganese produced by microbes and oxygen to see how strong the differences are.
NIKOLAY KHIZHNYAK