NASA presents new evidence of ancient conditions favorable to life on Mars

On the left is
On the left is “Wopmay” rock, in Endurance Crater, Meridiani Planum, as studied by the Mars Rover Opportunity. On the right are the rocks of the “Sheepbed” unit in Yellowknife Bay, in Gale Crater, as seen by the Mars Rover Curiosity (Image NASA/JPL-Caltech/Cornell/MSSS)

Yesterday, NASA presented the results of the analysis of a rock sample taken last month in Gale Crater on Mars by the Mars Rover Curiosity. The analysis confirms that in a very ancient era climatic conditions on Mars were suitable to support life forms.

In the analysis of rock sample taken by the Mars Rover Curiosity, scientists have identified sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, all key elements for the development of life forms of the type we know. Curiosity is exploring an area called Yellowknife Bay, which in an ancient epoch was part of a river or a lake bed in which the conditions for the development of life forms were favorable.

In particular, two instruments of the Mars Rover Curiosity have shown the conditions favorable to support life: Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (Chemin). They showed that the rock contains clay minerals, sulfates and other chemical compounds. An important fact is that the ancient wet environment wasn’t strongly oxidizing, acidic or extremely salty as other existing on the ancient Mars.

The clay minerals found are the products of the reaction of relatively fresh water with igneous minerals such as olivine, which is also present in the sediment. It’s not clear whether the reaction occurred in the sedimentary deposit, during the sediment transport or in region of origin of the sediment. Calcium sulphate was also found together with clay, suggesting that the soil is neutral or slightly alkaline.

A surprise for the scientists came from the discovery of a mixture of chemical compounds oxidized, partially oxidized and non-oxidized. This is the type of chemistry used by terrestrial microbes to generate the energy used in their vital functions. Those compounds, together with sulphates and sulphides, indicate a possible source of chemical energy for microorganisms.

There’s a little luck in this discovery. Originally, the scientists of the Curiosity mission wanted to send the rover directly to the mountain in the middle of the Gale Crater and only after the landing they decided to have it make a detour to examine the area called Yellowknife Bay. The scientists have conquered this luck recognizing that the area is interesting from a geological point of view by examining the preliminary data.

A rock that looks like the analyzed one was photographed by the panoramic camera (Pancam) of the Mars Rover Opportunity in 2004 in the Endurance crater, in the region called Meridiani Planum. Curiosity is equipped with more sophisticated instruments so it can collect rock samples and carry out in-depth analyzes.

Further analyzes will be carried out in the area to confirm these results, also for the presence of other trace gases analyzed by the SAM instrument. There’s no evidence that on Mars in the past there were actually life forms but this is the most conclusive evidence yet found that conditions were favorable to life.

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