by The researchers suspect that two meteorites, which were found in the Sahara desert in 2023, could originally come from mercury, which would make them the first identified fragments of the innermost planet of the solar system.
The least studied and mysterious of the rocky planets of the solar system is so close to the sun that it is difficult for probes to explore them. So far, only two unwritten spacecraft have visited it – Mariner 10, which was started in 1973, and Messenger, who was launched in 2004. A third, Bepicolombo, is on the way and will enter the planet around the orbit at the end of 2026.
Scientists know little about Mercury’s geology and composition, and they have never been able to study a fragment of the planet that landed on earth as a meteorite. In contrast, there are more than 1,100 known samples from the moon and Mars, an organization that cataloged all known meteorites in the database of the meteoritic society.
These 1,100 meteorites came as fragments during the asteroid effects of the surfaces of the moon and Mars before they made their way to earth after a trip through the room.
In collisions, it is likely that every planet will emit fragments of itself. Although Venus is closer to us than Mars, the larger gravitational suit and the thick atmosphere can prevent the introduction of impregnation. However, some astronomers believe that mercury should be able to create meteors.
“Based on the crowd of moon and Mars meteorites, we should have around 10 meteorites from Mercury,” said Ben Rider-Stokes, a postdoctoral researcher in Achondrite Meteorite at the Open University of the United Kingdom and Senior Author of a study on the ICARUS meteorites published in June.
“However, Merkur is much closer to the sun, so everything that is expelled by mercury also has to escape the gravity of the sun to get to us. It is dynamically possible, only much harder. Nobody has confidently identified a meteorite that still has a meteorite of mercury from Mercury from planets, and added that it was also unable to get from the planet be to regain physical samples from the planet.
If the two meteorites found in 2023-Northwest Africa 15915 (NWA 15915) and KSAR Ghilane 022 (KG 022)-as from mercury, they would significantly drive the understanding of the planet scientists. But he and his co -authors are the first to warn a few discrepancies if they correspond to these space rocks that scientists know about Mercury.
A fragment of the Northwest Africa in 15915, a meteorite in 2023, that the authors of the study also believe that they can come from mercury. – Jared Collins
The biggest is that the fragments have formed about 500 million years earlier than the surface of mercury itself. According to Rider-Stokes, however, this finding could be based on inaccurate estimates, which makes a conclusive assessment unlikely. “Until we return material from mercury or visit the surface,” he said, “it will be very difficult to prove safely and refute a Mercurian origin for these samples.”
However, there are some compositions that indicate that the meteorites may have a connection to the planet that is closest to the sun.
Notes on Mercurian origin
It is not the first time that well -known meteorites have been associated with mercury. The former best candidate, which is based on the interest aroused in astronomers, was a fragment called Northwest Africa (NWA) 7325, which was reportedly found in South Morocco in early 2012.
Rider-Stokes said that this was the first meteorite that may have been associated with mercury: “It got a lot of attention. Many people got very excited.” However, a further analysis showed a chronological wealth in contradiction to the predicted surface composition of mercury.
Astronomers have recently proposed that a class of meteorites named Aubrites – from a small meteorite that ended up in Aubres, France in 1836, could come from the mantle from Mercury, the layer below the surface. However, the meteorites lack chemical compatibility with what astronomers know about the surface of the planet, said Rider-Stokes. “This is what is so exciting about the rehearsals we have studied – they have a kind of perfect chemistry to be representative of mercury,” he said.
Most, which is known about Mercury’s surface and composition, comes from the Messenger -probe of the NASA, which evaluated the make -up of the crust of the planet from the orbit. Both meteorites from the study, analyzed with several instruments, including an electron microscope, contain, olivine and pyroxen. Two from messenger as messenger on mercury, brave minerals.
The new analysis also showed a complete lack of iron in the Space Rock samples, which corresponds to the assumptions of the scientists about the surface of the planet. However, the meteorites only contained trace quantities of plagioclas, a mineral that was assumed to dominate the surface of the mercury.
A view of mercury that is created using pictures from Messenger’s main mission. – NASA/Johns Hopkins University Applied Physics Labor/Carnegie Institution in Washington
However, the biggest point of uncertainty is still the age of the meteorites. “They are about 4.5 billion years old,” said Rider-Stokes, “and most of the Mercury interface is only about 4 billion years old, so there is a difference of 500 million years.”
However, he said that this discrepancy is not sufficient to exclude a Mercurian origin, since the messenger’s data was also used to assess the age of the surface layer of Mercury.
“These estimates are based on impact cratering models and not on absolute age dating and may not be exactly exactly,” said Rider-Stokes. “This does not mean that these samples do not have good analogue for regional areas on the surface of mercury or the early Mercurian crust, which is not visible on the modern surface of the mercury.”
With more modern instruments that are now available, Bepicolombo, the European Space Agency examination, which will begin in early 2027, can possibly have long-term questions about the planet, e.g. B. where it has formed and whether it has water.
The material, which comes from other planetary bodies, helps astronomers to understand the type of building blocks of the early solar system, according to Rider-Stokes, and the identification of mercury fragments would be particularly important, since a mission to collect and bring them back on the planet would be extremely difficult and more expensive.
Notes on planet formation
Sean Solomon, director of Mercury’s NASA messenger mission, said in an e -mail that he believes that the two meteorites described in the recent work probably did not come from Mercury. Solomon, an extraordinary research scientist at Columbia University in New York City, was not involved in the study.
The main reason why Solomon quoted for his doubts is that the meteorites formed much earlier than the best estimates for the age of rocks on Mercury’s surface. But he said he thinks the samples still have a research value.
“Nevertheless, the two meteorites have many geochemical properties with mercury surface materials, including little to no iron … and the presence of sulfuric minerals,” he added. “These chemical characteristics have been interpreted to indicate that mercury from precursors that are much more chemical than those, the earth and the other inner planets formed.
Solomon also noticed that it was difficult to convince the planetary science community that there were rehearsals from Mars in meteorite collections and that there is a precise match of their chemistry with data about the surface of Mars, which were absorbed by the Viking probes to convince the researchers more precisely. Lunar meteorites were also not generally recognized that they were in meteorite collections until the existence of Martian meteorites was demonstrated in the 1980s, he added, although the Apollo and Luna missions were more than a decade.
As soon as the samples come from a planetary body, according to Solomon, they can provide decisive information that is not available from remote sensing through a surrounding spaceship about the time of the most important geological processes, the history of the internal melting of the body and the information on the formation of planets and the early solar system processes.
Rider-Stokes plans to continue the discussion about these meteorites at the annual conference of the meteoritic society, which takes place this week in Perth. “I will discuss my results with other academics all over the world,” he said. “At the moment we cannot definitely prove that these do not come from Mercury. Until this is possible, I think that these samples will remain a major topic of the debate in the entire planetary science community.”
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