How do Martian meteorites get to Earth? Martian meteorite and terraces Meteorites from Mars.
A Martian meteorite recently discovered on Earth may be the missing link between the planet's warm, wet past and its cold, dry present.
A Martian meteorite recently discovered on Earth may be the missing link between the planet's warm, wet past and its cold, dry present. The rock, found in 2011 in Morocco, is part of a previously unknown class and could fill gaps in scientists' knowledge of the geological history of the red planet.
The meteorite, called NWA 7034, is very different from other rocks from Mars that have been studied by experts on Earth.
NWA 7034 contains about 10 times more water (about 6 thousand parts per million) than any of the 110 other known meteorites that fell to Earth from Mars. This suggests the meteorite may have come from the surface of the planet rather than from its depths, says planetary scientist Carl Agee of the University of New Mexico.
Previously studied Martian meteorites, known as SNC samples, apparently come from a less explored part of the planet's landscape. Perhaps they broke off from Mars as a result of an asteroid impact in a certain region of the planet. But the most recent sample is more typical of the surface of Mars.
Experts believe that NWA 7034 is a fossil from a volcanic eruption on the planet's surface that occurred about 2.1 billion years ago. The meteorite was once lava that cooled and hardened. The cooling process itself may have been aided by water on the Martian surface, which ultimately left its mark on the meteorite's chemistry.
Scientists were also interested in the age of the meteorite. Most SNC samples date back only about 1.3 billion years, with the oldest meteorite being 4.5 billion years old. NWA 7034 represents the transition between the oldest and youngest Martian meteorite discovered on Earth.
“Many scientists believe that Mars was warm and wet early in its history, but that the climate changed over time,” explains Egi. The red planet eventually lost its atmosphere and became a cold, dry desert. The new meteorite belongs to the transition period between these extremes, making it an important find for scientists hoping to learn how the Martian climate changed.
Ega's findings are supported by data collected by Mars rovers and spacecraft orbiting the planet. The geochemical composition of the new meteorite exactly matches the composition of rocks analyzed by Mars rovers on the surface of the red planet.
Researchers confirmed the Martian origin of the meteorite using a method of exclusion and research that lasted as long as six months. Based on the age of the stone, they realized that it could not come from an asteroid - they are all much older than 2.1 billion years, with an average age of about 4.5 billion years.
“We knew he had to be from a planet,” says Agee. Mercury was not among the possible options, since the composition of the volcanic meteorite did not match the composition of the surface of the planet closest to the Sun. Venus didn't come either. Scientists speculate that the surface of this planet is too dry for rocks containing water, like NWA 7034.
Mars was the only viable option, and there is ample evidence of similarities to rocks studied during Mars missions.
And they are considered incredibly valuable samples, since they represent unique time capsules from the geological past of Mars. These meteorites by their nature provide us with samples of Mars without any space missions.
"While robotic missions to Mars continue to attempt to shed light on the planet's history, the only samples from Mars available for study on Earth are Martian meteorites," said study lead author Lauren White of NASA's Jet Propulsion Laboratory. “On the ground, we can use several analytical techniques to look deeper into the meteorite and shed light on the history of Mars. These samples may hold clues to their planet's habitable past. As more and more Martian meteorites are found, the cumulative research provides more attributes of ancient habitation on the planet. "In addition, if these meteorite studies are confirmed by modern robotic observations of Mars, the mystery of the planet and its wet past may be solved."
In their study, the scientists describe features associated with Martian clay deposits - microtunnels similar to those found in samples Y000593. Compared to terrestrial samples, the Martian forms appear to be very similar to the biohydrothermal textures of basalt glasses. Basically, this means that the Martian meteorite contains features that resemble mineral formations created by bacteria on Earth.
Another factor is the discovery of nanometer- to micron-sized balls located between layers of rock in the meteorite. These spherules are distinct from the minerals within the rock and are rich in carbon, which may indicate biological interactions within the rock material.
Could this be evidence of Martian bacteria chewing Martian rocks? Unfortunately, this conclusion cannot be drawn from the study, so the researchers avoid the word “life” in their works - replacing it with “biogenic origin” and “biotic activity.”
“We cannot rule out the possibility that carbon-rich areas may be the product of non-biotic mechanisms,” the scientists write. So-called abiotic mechanisms mean that the effects are not caused by microbial life, but by chemical reactions in the geology of the stone. “However, textural and compositional similarities to features in terrestrial samples that are clearly interpreted as biogenic suggest the intriguing possibility that Martian features are shaped by biotic activity.”
Other astrobiologists literally supported the scientists’ caution with applause. "It's good that they didn't raise a false alarm and speculate about 'life on Mars' by admitting they don't know for sure what the origins of these channels are," said Louise Preston from the UK.
“This is not a smoking gun,” White said. - We can never rule out the possibility of terrestrial contamination. But these features are nevertheless interesting and show that further research on meteorites needs to be continued.”
With the controversial 1996 ALH84001 in mind, many researchers react aggressively to any research that emerges into the question of life on Mars and other planets, and skepticism is often too high. Therefore, until we can find and analyze DNA of extraterrestrial origin, or find intact samples on Mars, work on the question will be presented as “exciting, but not definitively verified.”
While studying, scientists came to new discoveries. For example, they learned about the climate of Mars. Zircons, minerals that can be found in meteorites, allowed scientists to draw conclusions. As is known, zircons are also present on Earth; they are formed due to the cooling of lava. Is this the case on Mars? Let's look further.
Why is this a unique find?
Dr. M. Gumayun, who is involved in research, says that Martian meteorite "Black Beauty" was discovered in Morocco. It originally belonged to a meteorite dealer and was later sold to a government collector. Some other stones with similar properties went to a collector in France.
But let's get back to "Black Beauty", the presented meteorite went to a group of Gumayun researchers, who determined that it was a breach - a stone obtained by combining several stones. Moreover, they learned that the age of the zircons is determined to be billions of years old, and declared that the origin of the meteorite was high mountain.
What makes the found object unique? Because before this, meteorites were found whose age was much younger - up to 1.4 billion years. And Black Beauty is an ancient Martian representative.
What information did “Black Beauty” give?
Gave useful data on the surface of Mars. Young rocks occupy only 15% of the planet. And it was the stones from there that flew to Earth.
"Black Beauty" people got it just in time. The surface of Mars is now being actively studied with the help of rovers and the Curiosity laboratory. It is known that this stone left the red planet about 5 million years ago, but it reached Earth relatively recently, as evidenced by its fresh appearance.
What else is remarkable about the found meteorite? It allowed us to identify 2 control points - 1.4 billion years and 4.4 billion years. And this makes it possible to understand how the climate of Mars has changed over time. Taking into account the characteristics of other meteorites, it will be possible to draw conclusions about how the Red Planet began.
Accordingly, studying "Black Beauty" will continue. Meteorite, which weighs only 320 grams, will provide answers to our most pressing questions. For example, the fact that it contains 6 times more water than other stones found makes it possible to claim that there used to be water on Mars. Perhaps some forms of life existed there at that time. But then, for some reason, the warm climate became cold.
Martian meteorite- a rock that formed on the planet hit and was then expelled from Mars by the impact of an asteroid or comet, and finally landed on Earth. Of the more than 61,000 meteorites that have been found on Earth, 132 have been identified as Martian. These meteorites are thought to be from Mars because they have elemental and isotopic compositions that are similar to the rocks and atmospheric gases analyzed by the Mars spacecraft. On October 17, 2013, NASA reported, based on analysis of argon in the Martian atmosphere by the Mars Curiosity rover, that certain meteorites found on Earth that were thought to be from Mars were actually from Mars
The term does not apply to meteorites found on Mars, such as Thermal Scutum Rock.
On January 3, 2013, NASA reported that the meteorite, named NWA 7034(named "Black Beauty"), found in 2011 in the Sahara Desert, was determined to be from Mars and was found to contain ten times the water of other Mars meteorites found on Earth. The meteorite was determined to form 2.1 billion years ago during the Amazonian geological period on Mars
Story
By the early 1980s, it was obvious that the SNC group of meteorites (Shergottites, Nakhlites, Chassignites) were significantly different from most other meteorite types. Among these differences were younger ages of formation, different oxygen isotopic composition, the presence of aqueous tilt products, and some similarity in chemical composition to studies of Martian surface rocks in the 1976 Viking landers. Several workers suggested that these features implied the origin of the SNC meteorites from a relatively large superior authority, perhaps Mars (e.g. Smith and etc. and Treyman and etc.) . Then in 1983, various trapped gases were reported in impact-formed shergottite glass EET79001, gases that closely resembled those in the Martian atmosphere as analyzed by Viking. These trapped gases provided direct evidence for a Martian origin. In 2000, an article by Treeman, Gleason and Bogard gave an overview of all the arguments used to conclude the SNC meteorites (of which 14 were found at the time) were from Mars. They wrote, "There appears to be a small chance that SNCs are not from Mars. If they were from another planetary body, then it would have to be essentially identical to Mars, as is now understood."
Subdivision
As of January 9, 2013, 111 of the 114 Martian meteorites are divided into three rare groups of achondritic (stony) meteorites: shergottites (96), nakhlites (13), chassignites(2), and otherwise (3) (which includes the oddball Allan Hills meteorite 84001 usually placed within a certain "OPX group"). Consequently, Martian meteorites in general are sometimes referred to as SNC group. They have isotope ratios that are said to be compatible with each other and incompatible with Earth. The names come from the location of where the first meteorite of their type was discovered.
Shergottites
Approximately three-quarters of all Martian meteorites can be classified as shergottites. They are named after the Shergotty meteorite, which fell on Sherghati, India in 1865. Shergottites are igneous rocks of mafic to ultramafic lithology. They fall into three main groups, basaltic, olivine-phyric (such as the Tissint group found in Morocco in 2011) and lherzolitic shergottites, based on their crystal size and mineral content. They can be categorized alternatively into three or four groups based on their rare earth element content. These two classification systems do not line up with each other, hinting at the complex relationships between the various source rocks and magmas from which shergottites formed.
shergottites appear to have crystallized only 180 million years ago, which is a surprisingly young age considering how ancient most of Mars' surface appears to be and the small size of Mars itself. Because of this, some have defended the idea that shergottites are significantly older than this. This "Shergottite Age Paradox" remains unresolved and is still an area of active research and debate.
It has been shown that nakhlites were awash in liquid water approximately 620 million years ago and that they were expelled from Mars approximately 10.75 million years ago by an asteroid impact. They fell to Earth within the last 10,000 years.
The Martian origin of meteorites was established by comparing the isotopic composition of the gas contained in meteorites in microscopic quantities with data from an analysis of the Martian atmosphere made by the Viking spacecraft.
Origin of Martian meteorites
The first Martian meteorite, named Nakhla, was found in the Egyptian desert in 1911. Its meteorite origin and belonging to Mars were determined much later. Its age was also determined - 1.3 billion years.
These stones ended up in space after large asteroids fell on Mars or during powerful volcanic eruptions. The force of the explosion was such that the ejected pieces of rock acquired a speed sufficient to overcome the gravity of Mars and even leave the near-Martian orbit (5 km/s). Thus, some of them were caught in the Earth's gravitational field and fell to Earth as meteorites. Currently, up to 0.5 tons of Martian material per year falls on Earth.
Meteorite evidence of life on Mars
In August 1996, the journal Science published an article about a study of the ALH 84001 meteorite, found in Antarctica in 1984. Isotope dating showed that the meteorite originated 4-4.5 billion years ago, and was thrown into interplanetary space 15 million years ago. 13,000 years ago, a meteorite fell to Earth. Studying the meteorite using an electron microscope, scientists discovered microscopic fossils that resemble bacterial colonies, consisting of individual parts approximately 100 nm in size. Traces of substances formed during the decomposition of microorganisms were also found. The work was received ambiguously 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 accommodate DNA and RNA molecules. During subsequent studies, traces of terrestrial biocontaminants were found in the samples. Overall, the argument that the formations are bacterial fossils does not seem convincing enough.
In 2013, when studying the MIL 090030 meteorite, scientists found that the content of boric acid salt residues necessary to stabilize ribose was approximately 10 times higher than its content in other previously studied meteorites.
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Excerpt characterizing the Martian meteorite
It was impossible to fight when information had not yet been collected, the wounded had not been removed, the shells had not been replenished, the dead had not been counted, new commanders had not been appointed to replace the dead, and people had not eaten or slept.And at the same time, immediately after the battle, the next morning, the French army (due to that rapid force of movement, now increased as if in the inverse ratio of the squares of the distances) was already advancing by itself on the Russian army. Kutuzov wanted to attack the next day, and the whole army wanted this. But in order to attack, the desire to do so is not enough; there needs to be an opportunity to do this, but this opportunity was not there. It was impossible not to retreat to one transition, then in the same way it was impossible not to retreat to another and a third transition, and finally on September 1, when the army approached Moscow, despite all the strength of the rising feeling in the ranks of the troops, the force of things demanded so that these troops march for Moscow. And the troops retreated one more, to the last crossing and gave Moscow to the enemy.
For those people who are accustomed to thinking that plans for wars and battles are drawn up by commanders in the same way as each of us, sitting in his office over a map, makes considerations about how and how he would manage such and such a battle, questions arise as to why Kutuzov didn’t do this and that when retreating, why he didn’t take up a position before Fili, why he didn’t immediately retreat to the Kaluga road, left Moscow, etc. People who are used to thinking like this forget or don’t know those inevitable conditions in which the activities of every commander in chief always take place. The activity of a commander does not have the slightest resemblance to the activity that we imagine, sitting freely in an office, analyzing some campaign on the map with a known number of troops, on both sides, and in a certain area, and starting our considerations with what some famous moment. The commander-in-chief is never in those conditions of the beginning of some event in which we always consider the event. The commander-in-chief is always in the middle of a moving series of events, and so that never, at any moment, is he able to think through the full significance of the event taking place. An event is imperceptibly, moment by moment, cut into its meaning, and at every moment of this sequential, continuous cutting of the event, the commander-in-chief is in the center of a complex game, intrigue, worries, dependence, power, projects, advice, threats, deceptions, is constantly in the need to respond to the countless number of questions proposed to him, always contradicting one another.
Military scientists tell us very seriously that Kutuzov, much earlier than Filey, should have moved troops to the Kaluga road, that someone even proposed such a project. But the commander-in-chief, especially in difficult times, faces not one project, but always dozens at the same time. And each of these projects, based on strategy and tactics, contradicts one another. The commander-in-chief's job, it would seem, is only to choose one of these projects. But he cannot do this either. Events and time do not wait. He is offered, let’s say, on the 28th to go to the Kaluga road, but at this time Miloradovich’s adjutant jumps up and asks whether to start business with the French now or retreat. He needs to give orders now, this very minute. And the order to retreat takes us off the turn onto the Kaluga road. And following the adjutant, the quartermaster asks where to take the provisions, and the head of the hospitals asks where to take the wounded; and a courier from St. Petersburg brings a letter from the sovereign, which does not allow the possibility of leaving Moscow, and the rival of the commander-in-chief, the one who undermines him (there are always such, and not one, but several), proposes a new project, diametrically opposed to the plan for access to the Kaluga road; and the forces of the commander-in-chief himself require sleep and reinforcement; and the venerable general, bypassed by a reward, comes to complain, and the inhabitants beg for protection; the officer sent to inspect the area arrives and reports the exact opposite of what the officer sent before him said; and the spy, the prisoner and the general doing reconnaissance - all describe the position of the enemy army differently. People who are accustomed to not understanding or forgetting these necessary conditions for the activity of any commander-in-chief present to us, for example, the situation of the troops in Fili and at the same time assume that the commander-in-chief could, on September 1st, completely freely resolve the issue of abandoning or defending Moscow, whereas in the situation of the Russian army five miles from Moscow this question could not have arisen. When was this issue resolved? And near Drissa, and near Smolensk, and most noticeably on the 24th near Shevardin, and on the 26th near Borodin, and on every day, hour, and minute of the retreat from Borodino to Fili.
