Meteorites from Mars. How do Martian meteorites get to Earth? Meteorite evidence of life on Mars
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.”
Back in the early 1980s, scientists were skeptical that meteorites from Mars could be found on Earth, since they believed that ejected surface Martian rocks as a result of large debris from asteroids and comets falling onto the planet would not be able to overcome the gravitational forces of Mars.
Fragments of the planet Mars that fell to Earth in the form of meteorites have been found more than once, but evidence that these meteorites came from Mars was obtained when it was established that the isotopic composition of the gas contained in meteorites in microscopic quantities corresponds to data from an analysis of the Martian atmosphere made by Viking devices.
Once the Martian origin of some samples became undeniable, theorists were forced to reconsider the physics of this process.
Martian meteorites are quite rare visitors arriving from Mars. Of the more than 61,000 meteorites that have been found on Earth, only 120 have been identified as Martian.
All of them were, for various reasons, torn away from the Red Planet and then spent millions of years in orbit between Mars and Earth, eventually falling onto it.
The Shergotti Martian meteorite, preserved at the National Museum of Natural History in Washington.
Shergotti is a Martian meteorite weighing about 5 kg that fell to Earth near the village of Shergotti in India on August 25, 1865. Is the first example of shergottites. This is how meteorites similar to it, consisting of basaltic rocks, were subsequently called. The meteorite belongs to the class of SNC meteorites, which are of Martian origin.
Shergotti Martian meteorite close-up
The Shergotti meteorite is relatively young by galactic standards - it is about 175 million years old. Presumably it was knocked out of Mars after a large meteorite fell into a volcanic region of Mars. Scientists from the Massachusetts Institute of Technology who studied the meteorite concluded that at least two percent of the water in the volcano's magma would have been needed to crystallize the minerals contained in the meteorite.
Meteorite NWA 7034, "Black Beauty"
The baseball-sized, 320-gram meteorite, officially named North West Africa (NWA) 7034, or informally "Black Beauty," is the second oldest Martian meteorite discovered on Earth. It is more than two billion years old.
The meteorite was donated to the University of New Mexico by an American who bought it from Bedouins in Morocco, and a series of tests confirmed that it came to Earth from Mars.
Martian meteorites NWA 7034
This is a special type of stone that was formed as a result of a volcanic eruption on Mars. The meteorite's composition is similar to soil samples obtained by the Curiosity rover on the surface of Mars. But its water content is twenty times higher than in other previously found meteorites.
It is believed that ancient Mars was warmer and wetter, but it lost much of its atmosphere and the water on its surface disappeared. The planet turned into the cold and dry desert that can be seen today.
The meteorite likely formed during a climate transition when the Red Planet was losing its atmosphere and surface water.
Martian meteorite Dhofar 019
A brownish-gray meteorite weighing 1056 g was found in the Oman desert on January 24, 2000.
In terms of its structure, it is Martian basalt, close to shergottite.
Martian meteorite Zagami
An extraordinary event occurred in the fall of 1962, when a farmer from the Nigerian village of Zagami, after having lunch, went to his property to drive away crows from his corn fields. While working, he heard a loud crash, after which the shock wave threw him several meters away. The source of the shock wave turned out to be a stone weighing approximately 20 kilograms. Then the farmer, naturally, did not yet know that in front of him lay a meteorite that had fallen to Earth directly from Mars.
Soon after rumors spread about the incident, researchers arrived at the crash site and, convinced of the value of the meteorite, placed it in the Museum of Natural History in Washington.
Based on its chemical composition and isotope ratios, the meteorite was classified as a shergottite group. Basaltic rocks with high dynamic stress structures indicate that the sample was dislodged and deformed by a powerful impact event.
The black veins of the meteorite glass contain gas bubbles from the atmosphere of Mars.
The meteorite is 180 million years old.
Section of the Tissint meteorite, Morocco
The meteorite, which fell on July 18, 2011 near the Moroccan city of Tissint, consists of small “capsules” containing Martian air.
Astrogeologists discovered that the meteorite is a kind of “stained glass window” made of many layers of different minerals, including maskelinite - meteor glass that is formed when a celestial body collides with the surface of the planet.
Meteorite of Martian origin found in Morocco, Tissint
The high content of Martian soil in the meteorite can be explained by the fact that it penetrated into a crack inside the volcanic rock along with streams of liquid water that existed in ancient times on Mars.
Unlike other previously studied Martian meteorites, it contains abnormally high proportions of light rare earth elements: lanthanum, cerium, and some other metals.
The meteorite is a shergottite, a very young rock formed 150 to 200 million years ago.
Section of meteorite NWA 6963
Meteorite NWA 6963, found in September 2011 in Morocco, belongs to the type of shergotites, the name of which was given by the first meteorite of this kind found in the Indian village of Shergotti in India, in 1865. The meteorite was well studied and analysis results showed that it was formed on Mars.
Meteorite NWA 6963
The perimeter of the found stone shows a crust of fusion from the high temperature of entry into the Earth's atmosphere. This is a new example of a Martian shergottite meteorite, found in September 2011 in Morocco. This meteorite is quite young, it was formed only 180 million years ago. It is assumed that volcanic activity was still present on Mars at that time. Volcanic flows usually contain the youngest part of the planet. This piece of young Mars was driven away by a meteor and landed on an old two-hundred-year-old lava flow on Earth after many years of space travel.
The Martian rock meteorite (chondrite) NWA 6954 was found in Morocco in 2011. This is a very beautiful meteorite with multi-colored chondrules in the matrix.
ALH 84001 (Allan Hills 84001) is a meteorite weighing 1.93 kilograms, found on December 27, 1984 in the Alan Hills Mountains in Antarctica. It gained worldwide fame in 1996 after NASA scientists announced the discovery of fossilized microscopic structures resembling fossilized bacteria in the meteorite material.
Scientists have hypothesized that the origin of the ALH 84001 meteorite on Mars took place at a time when there was water on the planet.
According to the theory, the rock broke off from the surface of Mars as a result of a collision between the planet and a large cosmic body about four and a half billion years ago, after which it remained on the planet. About 15 million years ago, as a result of a new collision of Mars with an asteroid, it ended up in space, and only 13 thousand years ago it fell into the Earth’s gravitational field. These data were established as a result of radiocarbon analysis, strontium dating, and potassium-argon radiometry.
The oldest Martian meteorite, ALH 84001, is very similar to volcanic rocks found on the surface of Mars by NASA's Spirit and Opportunity rovers.
Nakhla is a famous Martian meteorite discovered in Egypt.
Early in the morning of June 28, 1911, across a field near the village of Denshal, not far from Nakhla
The dog wandered carelessly, unaware that in a matter of minutes he would go down in history. Walking next to him was a shepherd, Mohammoud Ali Effendi Hakim, who suddenly heard the roar of an explosion in the upper atmosphere, after which the entire field was enveloped in smoke.
The shepherd escaped with a slight fright, and the dog disappeared: one of the fragments of the fallen 10-kilogram meteorite landed directly on the dog. Hakim colorfully told the newspapermen who arrived in time about what he had seen, and they nicknamed the dog “the first victim of the meteorite.”
However, the remains of the dog were never found, however, references to it remained in scientific works about this meteorite, and the “dog Nakhla” himself became a legend among astronomers.
Meteorite fragments were found within a radius of five km from the epicenter of the explosion. Some parts sank into the ground to a depth of more than one meter.
Nakhla was the first meteorite from Mars to show evidence of water on the planet. The rock contained carbonates and minerals that could have been the products of a chemical reaction with water. The content of the 13 C isotope is higher than in terrestrial rocks, which indicates the Martian origin of the meteorite.
The age of the meteorite was also determined - 1.3 billion years.
It is believed that nakhlites formed in the large volcanoes of Tharsis or Elysium on Mars.
Martian meteorite Lafayette
One of the most interesting meteorites of Mars. It is named after the city of Lafayette, Indiana, where it was identified as a meteorite in 1931. The exact place and date of his fall are not known.
Isotopic analysis methods clarified its age. Lafayette landed on Earth 3000-4000 years ago. Compositionally, Lafayette is similar to the Nakhla meteorite, but contains more extraterrestrial water. Lafayette has a weight of 800 grams and a pronounced melting bark
Close-up of the Oilean Ruaidh meteorite, found on Mars in September 2010 by the Opportunity rover near Endeavor Crater
Photo of an iron meteorite found by NASA's Opportunity rover on Mars. It is the first meteorite found on another planet that is composed primarily of iron and nickel.
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.
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Explore Martian meteorites– objects from Mars: how many fell to Earth, the first Martian meteorite Nakhla, research and description with photos, composition.
Martian meteorite- a rare type of meteor that came from the planet Mars. Until November 2009, more than 24,000 meteors had been found on Earth, but only 34 of them were from Mars. The Martian origin of the meteors was known from the composition of the isotopic gas contained in the meteors in microscopic quantities; an analysis of the Martian atmosphere was carried out by the Viking spacecraft.
The emergence of the Martian meteorite Nakhla
In 1911, the first Martian meteorite, called Nakhla, was found in the Egyptian desert. The occurrence and belonging of the meteorite to Mars was established much later. And they established its age - 1.3 billion years. These stones appeared in space after large asteroids fell on Mars or during massive volcanic eruptions. The force of the explosion was such that the ejected pieces of rock acquired the speed necessary to overcome the gravity of the planet Mars and leave its orbit (5 km/s). Nowadays, up to 500 kg of Martian rocks fall to Earth in one year.
In August 1996, the journal Science published an article about a study of the ALH 84001 meteorite, found in Antarctica in 1984. A new work has begun, centered around a meteorite discovered in an Antarctic glacier. The study was carried out using a scanning electron microscope and identified "biogenic structures" inside the meteor that could theoretically have been formed by life on Mars.
The isotope date demonstrated that the meteor appeared about 4.5 billion years ago, and having entered interplanetary space, fell to Earth 13 thousand years ago.
"Biogenic structures" discovered on a meteorite section
By studying the meteor using an electron microscope, experts found microscopic fossils that suggested bacterial colonies made up of individual parts measuring approximately 100 nanometers in volume. Traces of drugs produced during the decomposition of microorganisms were also found. Proof of a Martian meteor requires microscopic examination and special chemical analyses. A specialist can attest to the Martian occurrence of a meteor based on the presence of minerals, oxides, phosphates of calcium, silicon and iron sulfide.
The known specimens are invaluable finds because they represent quintessential time capsules from Mars' geological past. We obtained these Martian meteorites without any space missions.
At the beginning of December last year, we talked about the conclusions of scientists who came to the conclusion that life could very likely appear on Mars. In support of such amazing conclusions, they spoke about the presence of chemical elements generated by biological activity in a stone that they found... on Earth. According to experts, the Martian origin of the fragment discovered on July 18, 2011 is proven by its chemical analysis. “The rock contains extremely low levels of rare earth elements, which are characteristic of rocks on the surface of Mars,” they note in the published study. But how then could this stone from Mars get to us? Readers asked us the following questions:
— How could a stone of such small size be discovered on Earth? What mechanisms led to it leaving the Martian surface and reaching us? And vice versa, can a rock of N size from Earth end up on Mars?
— Please explain why Martian rocks fly away from the planet, contrary to all the laws of gravity, and fall to Earth?
— You say that the meteorite came from Mars. How could such a stone overcome the gravitational field of the planet? And can meteorites of terrestrial origin exist?
We asked these questions to Philippe Gillet of the École Polytechnique Fédérale de Lausanne, who was one of the study's co-authors. He explains it this way: “Some relatively large object struck the Martian surface with sufficient force to throw fragments of Martian rock out of the planet’s atmosphere.” It's similar to how water splashes when you throw a stone into a pond.
Experts even have relatively accurate data on how strong an impact is required to throw rock fragments into space. “The speed of an object is proportional to the gravitational force of the planet,” explains Philippe Gillet. “We know that on Mars it is 8-10 kilometers per second. Based on this parameter, the scatter and the crystal structure of the rock, we can estimate the mass of the object that hit the Martian surface and even calculate the size of the crater it left.”
“We believe that launching a rock the size of the Tissint meteorite into space would require an object ranging from hundreds of meters to several kilometers in diameter to hit the surface of Mars,” he continues. As a result, the stones receive a powerful impulse and follow a ballistic trajectory that can take them beyond the gravitational field of Mars. Stones wander through space until they fall into the gravitational field of some other celestial body. While traveling through space, these rock fragments are subject to active bombardment by solar particles, from which they were previously protected by the planet's soil. “This stream of particles affects the substance and creates special isotopes that can be counted and thereby determine the total time the stone spent in space,” says Philippe Gillet. “The Tissint meteorite wandered for approximately 700 thousand years before reaching the earth’s surface.”
Fragments of earth rocks are also floating around in space.
If such mechanisms work on Mars, do they also work on Earth? In other words, is it theoretically possible to stumble upon pieces of our good old Earth that were thrown onto other planets after a meteorite hit? “Of course,” replies Philippe Gillet. Even if those rare studies of the surface of other planets have not yet shown this. But they certainly exist there, because this kind of event (an impact from a sufficiently large and fast-moving object to eject rock fragments into space) occurred more often on Earth than on Mars. In fact, everything depends on the mass of the planet: the larger the celestial body, the greater the force of attraction it exerts on objects in its surroundings.
And since the Earth's mass is ten times greater than that of Mars, it attracts more wandering space objects. “On Earth, a meteorite with a diameter of 100 meters falls approximately once every five centuries. A meteorite with a diameter of 5 kilometers hits Earth once every 10-50 million years,” says Philippe Gillet. For comparison, the meteorite that ended the age of dinosaurs on Earth 65 million years ago was 10 kilometers in diameter. “Such an event occurs once every 100-500 million years,” the scientist believes. After such an impact, a huge amount of earthly rock ended up in space...