once the Sun was given about a third less heat than at present. Climate models usually take that on Mars there were conditions for the emergence on the surface of liquid water (not frozen), the planet must have, respectively, a dense atmosphere consisting of carbon dioxide, where the greenhouse effect.
a Recent study conducted by the American planetary Rover, Curiosity deny this assumption. I suppose that 3.5 billion years ago Mars had too little carbon dioxide, the greenhouse effect could melt the ice.
Problems provided the same rock where the Rover earlier found deposits of the ancient lake that may have existed on Mars billions of years ago. Further investigation gave a paradoxical result: the lack of climatic conditions, allowing the establishment of such a lake. In the studied samples with a rock Foundation, is not detected for a sufficient amount of the minerals of carbonates.
“We are surprised by the lack of carbonate minerals in the rock deposition, which was examined by the Rover. Indeed, it would be hard to watery water on ancient Mars – even if carbon dioxide in the atmosphere would be hundreds of times more than suggest that the samples of the studied rocks,” said Thomas Bristow from NASA Ames Research Center in Moffett field, California.
Since landing in Gale crater in 2011 the Rover Curiosity found no solution in any rock sample, which are considered to be coming from the bottom of the former lake. The CheMin instrument is able to detect solution, if you are within a few percent content of rock. A recent study conducted by a team of 14 scientists, led by Bristow, allowed to calculate the upper limit of the amount of carbon dioxide, if it is performed in the former Martian atmosphere. The result gives a few tens of millibars of carbon dioxide. Millibar is one thousandth of atmospheric pressure at sea level on Earth. For comparison, in the current atmosphere of Mars is dominated by the pressure below 10 mbar and 95%. it consists of carbon dioxide.
Carbon dioxide reacts in water with positively charged ions of magnesium and iron, forming carbonate minerals. Other minerals present in the studied rocks indicate that these ions actually present. In addition, minerals such as magnetyty and clay minerals are evidence that the conditions never become so acidic that carbonates were dissolved (which would be possible in too acidic groundwaters).
“long is a mystery why the orbit of Mars is not visible, too much carbonate. Still, you can explain that they are not visible as they are covered with dust, under the surface or are we just not looking in the right place. The results from Curiosity directly on the surface of the planet give a new impetus to ago marsjańskiemu paradoksowi. The first time we were looking for a solution in the course of research on the surface of the rocks, which we know they osadowymi stones from the bottom of the former lake,” says Bristow.
Scientists are trying to find an explanation for the paradox of emergence long ago, the lake and the lack of conditions for its formation. Perhaps the lake was not an open reservoir of liquid water, only it was covered with ice. If the ice is not too thick, can still occur deposits on the bottom of the lake. Unfortunately, the Rover Curiosity has not yet found evidence in Gale crater to exist there once the frozen lake. Mystery requires further research, current and planned Martian mission.
the Results of a study conducted by a team of Bristowa was published in the scientific journal “Proceedings of the National Academy of Science”.
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