The study of Martian meteorites has become an entirely new area of life on Mars.
As of March 27, 2017, out of 61,000 cataloged meteorites on Earth, 202 were classified as Martian meteorites. It is believed that the first Martian meteorite (Chassigny) was found during a fall in the French mountains of Ardennes in 1815. At the same time, its Martian origin was determined only in 2000. It is estimated that on average, up to 0.5 tons of Martian matter is deposited on Earth. According to other estimates, on average one Martian meteorite falls to Mars per month.
A study of the Martian meteorite ALH 84001, published in the journal Science on August 1996, has gained great popularity. Despite the fact that this meteorite was found in Antarctica in 1984, its detailed study was conducted only a decade later. Isotope dating showed that the meteorite appeared 4-4.5 billion years ago, and 15 million years ago it was released into interplanetary space. 13,000 years ago, a meteorite hit the Earth. While studying the meteorite with the help of an electron microscope, scientists found microscopic fossils resembling bacterial colonies consisting of separate parts of about 100 nm in size. Traces of substances produced by the decomposition of microorganisms were also found. The work was controversially received by the scientific community. Critics noted that the size of the found formations is 100-1000 times smaller than typical terrestrial bacteria, and their volume is too small to contain DNA and RNA molecules. Subsequent studies have found traces of terrestrial biocontamination in the samples.
The interest of the scientists was aroused by a fragment resembling a bacterium Later in 2011, a new study of the meteorite ALH 84001 was published, which showed that the temperature on ancient Mars was about 18 degrees Celsius.
In 2013, a study of another Martian meteorite, MIL 090030, was published, which found that the content of residual salts of boric acid needed to stabilize the ribose in it is about 10 times higher than its content in other previously studied meteorites.
In the same year, a study of the meteorite NWA 7034, found in Morocco in 2011, appeared. NWA 7034 contains about 10 times more water (about 6,000 particles per million) than any of the first 110 known meteorites to fall to Earth from Mars. This suggests that the meteorite may have originated from the planet's surface rather than its depths, says Planet Scientist Carl Aegie of the University of New Mexico. Experts believe that NWA 7034 is a fossil record of a volcanic eruption on the planet's surface that occurred about 2.1 billion years ago. Once a meteorite was lava that cooled down and hardened. The cooling process itself may have been facilitated by the water on the Martian surface, which eventually left its mark on the chemical composition of the meteorite.
In 2014, a new study was published on another Martian meteorite, Tissint, which fell in the Moroccan desert on July 18, 2011. The initial analysis of the space stone showed that there were small cracks on it that were filled with carbon-containing substances. Scientists have proved more than once that such compounds are of organic origin, but it was still unclear whether these tiny carbon inclusions are indeed traces of ancient Martian life. Chemical, microscopic and isotopic analyses of carbon material allowed researchers to deduce several possible explanations of its origin. Scientists have found characteristics that clearly exclude the Earth's origin of carbon compounds. They also accurately determined that carbon was present in the cracks of Tissinta before it broke away from the surface of Mars. Previous studies have suggested that carbon compounds were the result of crystallization at high temperatures in magma. But Gilles and his colleagues disprove this version: according to a new study, a more likely explanation is the scenario in which liquids containing organic compounds of biological origin, penetrated into the "mother" rock of Tissinta at low temperatures close to the surface of Mars.
The bottom line...
These conclusions are confirmed by some peculiarities of carbon material inside the meteorite, for example, the ratio of carbon-13 isotopes to carbon-12. It turned out to be much lower than the ratio of carbon-13 in the carbon of the Martian atmosphere, which was measured by the Martian rovers. In addition, the difference between these coefficients corresponds to that observed on the Earth, between a piece of carbon material, which has a purely biological origin, and carbon in the atmosphere. Researchers note that an organic compound could also be deposited on Mars along with primitive meteorites - carbonate chondrites.