Japanese scientists managed to establish the alien origin of organic compounds in a meteorite found in Antarctica 36 years ago.
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For several decades, scientists have been trying to understand whether organic compounds exist on Mars – and if so, where did they come from. Despite the fact that recent studies have provided convincing evidence of the presence of organic substances on this planet, researchers know very little about the age and origin of such molecules, as well as about their possible biochemical activity.
A group of Japanese scientists found organic substances that contain nitrogen in the carbonate minerals of the Martian meteorite. Article about this discovery published in the publication Nature communications. The molecules found have been preserved on the Red Planet since the Nooy period – the early era of the geological development of Mars, that is, they are about four billion years old. Since carbonate minerals usually precipitate from groundwater, this discovery indicates that once the neighboring planet was rich in moisture and organic matter, and accordingly – quite fit for the development of life.
Martian meteorites are pieces of rock thrown into space as a result of impacts of celestial bodies on the surface of Mars and then ended up on Earth. One of the most important Martian meteorites for science is ALH84001, found in 1984 in Antarctica. It was he who was studied by Japanese researchers.
ALH84001 contains quite large inclusions of carbonate minerals with organic elements, which makes it a popular research object. However, all previous attempts to analyze the organic substances contained in the meteorite were unsuccessful: due to contamination with Antarctic ice, it was extremely difficult to establish which of the molecules are actually from Mars.
For the new study, special sample preparation methods were used that helped get rid of the pollution problem. For example, scientists separated tiny grains with a diameter of no more than a human hair on a silver ribbon from the main meteorite. Then, contaminants were removed from these grains using an ultra-precise ion-beam device. For the detection of organic nitrogen, the X-ray absorption spectroscopy technique at the leading edge (µ-XANES) was used, which made it possible to detect nitrogen in minimal amounts and strictly in the composition of organic molecules.
Thorough testing of samples gave scientists the opportunity to affirmthat the detected molecules with a very high probability came to the Earth from Mars. The researchers also found that the proportion of nitrogen in the form of nitrate, one of the most powerful oxidizing agents on the Red Planet today, is minimal among these molecules. This suggests that the atmosphere of early Mars was much less oxidizing than what we are observing now.
According to the results of the study, scientists have quite a few questions. The most important of them – where did these organic substances come from on a neighboring planet. “At the dawn of the history of the Solar System, Mars was probably bombarded with significant amounts of organic matter – for example, from carbon-rich meteorites, comets, and dust particles. Some of them may have dissolved in the brine and ended up inside the carbonates, ”says one of the authors of the study, Atsuko Kobayashi, voicing the most likely version. However, it is possible that the organics formed already on Mars, in the process of chemical reactions.
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