Autonomous Martian scientific laboratory “Kuryositi” of the NASA aerospace agency, which has been engaged in research of the Red planet for several years, has made two amazing discoveries. First, the rover managed to confirm the assumption that the concentration of methane in the atmosphere of the planet changes with the change of seasons, and secondly, the apparatus found a very ancient organics. No, unfortunately, he did not find a living life, but he found traces of ancient organics that can say that at some point in history there could actually be living beings on the planet. The find was found at the bottom of a parched lake. Articles of scientists describing the discovery, published in the journal Science.
“The discovery of methane and organics on Mars are of great importance for the search for traces of life. “Curiosity” has already shown that the lake that covered the bottom of the Gale crater 3.5 billion years ago was potentially inhabited. Given the presence of organic matter on its day, now the question of the existence of Martian life has become even more urgent, “commented Inge Keith, a planetologist from the University of Utrecht (The Netherlands).
Scientists have long argued on whether there exist in the near-surface layers of the Martian soil – where potentially there is liquid water, an acceptable temperature and where cosmic rays – organic or microbial stocks do not penetrate almost.
At the first study of the atmosphere in 2012 and 2013, “Kyuriositi” could not find traces of methane. However, just a few months later, the sensors of the rover detected several bursts in the concentration of methane. According to other assumptions, these tracks could have been the result of some “lifeless” processes in the soil of Mars.
Ashvin Vasavada, the head of the scientific team of the rover “Churiosity”, and his colleagues gave an exhaustive answer to all critics, presenting the results of six-year observations of the concentration of methane in the atmosphere of Mars, and having made an astonishing discovery in a place that received the name of Mojave three years ago.
During six years of being on the Red Planet, the rover saw two Martian winters, autumn, spring and summer. This allowed Vasavad and his team to accurately measure the seasonal fluctuations of methane in the atmosphere of Mars, as well as to clarify the past results of measurements.
Planetologists are fully confident that the concentration of methane in the atmosphere of Mars grows during the summer, and falls during the winter, reaching concentrations of 2.5 and 6.5 parts per ten billion. The threefold increase in the proportion of methane in the summer air of Mars, as scientists emphasize, can not be explained by atmospheric processes or by the fact that the solar ultraviolet decomposes the organic fragments of asteroids falling on the red planet better.
All this indicates that methane is formed in the lower layers of the soil Mars, or as a result of microbial activity, or as a result of decomposition of clathrates, methane and water compounds, or due to some geothermal processes.
As sharp bursts of local methane concentration show, This gas accumulates inside the original micro-caves and reservoirs in the soil and periodically bursts outward.
At the end of 2012, John Grottinger, the former head of the scientific team of the rover “Curiosity”, announced the discovery, which, according to him , should have been on the pages of textbooks. However, two weeks later, when the news was already making the most fantastic rumors, NASA planetologists told about the discovery of perchlorates – primitive organic molecules – in the soil of Mars.
This immediately shook hopes for the discovery of the first traces of extraterrestrial life, since such molecules can form in soil as a result of “lifeless” chemical reactions and the interaction of other forms of organic matter with ultraviolet and cosmic rays.
However, frustration with perchlorates, as Grotzinger and his colleagues write, took second place in January 2015, when the rover reached the foot of Mount Sharp, the central peak at the bottom of the Gale crater, and began to study the chemical composition of cobblestones and rocks of one of the local elevations named Mojave.
The interest of scientists was attracted by the strange “banding” of clay and other rocks , formed at the bottom of the ancient Martian lake about 3.5 billion years ago. After drilling through the ground and studying its composition, planetologists discovered an amazing – a huge number of complex organic molecules.
The possibilities of the “Curiosity” mass spectrometer are very modest, but even they were enough to detect traces of thiophene, sulfur and butyrene compounds, methane ethanol, sulfur and methane, benzothiophene, as well as a large number of simple hydrocarbons, their aromatic “cousins” and a number of other molecules.
As Grottsinger and his colleagues emphasize, all these molecules were most likely part of a more complex organics. Because of solvent leakage, scientists had to conduct all experiments inside SAM only at high temperatures, 600-800 degrees Celsius, which was supposed to destroy all large molecules and split them into many small “tails.”
Approximately the same molecules were found near Mojave, in Confidence Hills, where the rover stopped a month later. Their presence, as scientists conclude, does not necessarily mean that life existed on Mars 3,5 million years ago. It indicates that in the waters of the Martian lakes there could be reactions that generated such a complex organics, and food sources for potential life were more diverse than previously thought.
Interestingly, the neighboring regions of the bottom of the Gale crater, where Curiosity first found traces existence of the lake, do not contain similar stocks of organic matter, despite their older age. According to scientists, this is due to the fact that they were exposed long enough compared to Mojave and Confidence Hills, and all the organic material had time to get out of them.
“Regardless of how this organics originated, its availability speaks of that there may be traces of life on the surface of Mars, despite the radiation and a large number of oxidants in its atmosphere. These tracks may be hidden beneath its surface or in rocks that fell on it several thousand years ago, “scientists conclude.