[ad_1]
Martian meteorites are pieces of the surface of Mars that were impacted in space by meteorite impacts, and that eventually reached Earth. They give bits of knowledge to Martian history.
One such meteorite is Allan Hills (ALH) 84001, named for the Antarctic region found in 1984, it is especially important.
It contains orange-colored carbonate minerals, which precipitated from the salty liquid water on Mars near the surface 4 billion years ago. As these minerals record the initial watery condition of Mars, numerous investigations have attempted to understand their unique chemistry and whether they can give evidence of ancient life on Mars.
Be that as it may, previous studies have experienced contamination with terrestrial material from Antarctic snow and ice, making it difficult to claim that the amount of organic material in the shooting star was genuinely Martian. Despite carbon, nitrogen (N) is an essential element for terrestrial life and a useful marker for the evolution of the solar system. However, due to past specialized restrictions, nitrogen had not yet been estimated in ALH84001.
In a new study, scientists from the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology, Japan, and the Japan Aerospace Exploration Agency’s Institute for Space and Astronautical Science have discovered organic material that contains nitrogen in minerals. of carbonate in ALH 84001. According to scientists, this organic material has likely been conserved for 4 billion years since the age of Noah on Mars.
Since carbonate minerals normally precipitate from groundwater, this finding recommends a rich and humid early Mars, which might have been habitable and favorable for life to begin.
Using state-of-the-art analytical techniques, scientists were able to study the nitrogen content of ALH84001 carbonates. Now, scientists are confident that the first substantial evidence of 4 billion-year-old Martian organic compounds containing nitrogen. “
Ground pollution is a serious problem for studies of extraterrestrial materials. To avoid such contamination, the team developed new techniques to prepare the samples. For example, they used silver tape in a clean ELSI lab to pluck the tiny carbonate grains, which are about the width of a human hair, from the host meteorite.
The scientists then further prepared these grains to remove potential contaminants from the surface with a focused scanning electron microscope ion beam instrument in JAXA. They also used a technique called the K-border nitrogen X-ray micro-absorption near-edge spectroscopy (μ-XANES), which allowed them to detect the nitrogen present in small amounts and determine what chemical form that nitrogen was in. . Nearby igneous minerals gave no detectable nitrogen, showing that the organic molecules were only in the carbonate.
After careful monitoring of the contamination, the scientists determined that the detected organics were probably truly Martian. They also determined that the contribution of nitrogen as nitrate, one of the solid oxidants on present-day Mars, was unimportant, and they proposed that early Mars probably did not contain strong oxidants. As researchers have suspected, it was less oxidizing than it is today.
There are many open-ended questions, such as where do these organic nitrogen-containing compounds come from?
Atsuko Kobayashi of the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology, Japan, said: “There are two main possibilities: either they came from outside Mars or they were trained on Mars. At the beginning of the history of the Solar System, Mars probably received a large amount of organic matter, for example from meteorites, comets and carbon-rich dust particles. Some of them may have dissolved in the brine and become trapped inside the carbonates. “
Alternatively, chemical reactions on early Mars may have produced the organic compounds with N at the site. Either way, they say, these findings show that there was organic nitrogen on Mars before it became the red planet we know today; Early Mars may have been more “Earth-like”, less oxidizing, wetter, and rich in organic matter. Maybe it was “blue”.
Magazine reference:
- Mizuho Koike, In Situ Conservation of Nitrogen Organic Compounds in Noachian Martian Carbonates. DOI: 10.1038 / s41467-020-15931-4
