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Mars, with its thin atmosphere, photographed from the Viking orbiter in the 1970s. The bright red atmosphere is due to the presence of Martian dust in the atmosphere and the composition of the rocks of Mars was discovered for the first time by viking landers.NASA / Viking 1
As the planets revolve around the Sun, well separated from each other, we tend to assume that they do not exchange hardware very often. The solar system can be a violent place, marked by asteroid strikes and cometary collisions, but the planets themselves are too large and massive to be affected by these phenomena. When large energy collisions have an impact on your planet, the worst, in general, is to create a crater and cover your world with debris.
The Meteor crater (Barringer), located in the Arizona desert, is more than 1.1 km in diameter and only represents an energy release of 3 to 10 megaTons. An asteroid attack of 300 to 400 meters would release 10 to 100 times more energy and could be large enough to send fragments of the Earth into space, ejecting from our world where she could travel to other places in the solar system.USGS / D. Roddy
But sometimes, if the impact is large enough, it can cause debris in space. Many moons of our solar system – including the moons of Earth, Pluto and Mars – were created from the coalescence of these debris after a giant impact. Part of the debris falls back on the planet, while the remaining materials are completely ejected from the planetary system.
In theory, materials from one planet can be transferred to another.
In practice, we know that this is true. Pieces of Mars have been found on Earth, and new ones are falling into our world every two or three years.
Structures on the meteorite ALH84001, of Martian origin. Some argue that the structures shown here may be an old Martian life, but others argue that it is simply a non-biogenic magnetite that could have a purely geochemical origin.NASA, 1996
The science of meteorites is fascinating, with more than 61,000 pieces of confirmed rock of alien origin found on Earth. The solar system is a diverse and complex place, and every body on which we landed or sampled is different from each other. The surface rocks on Venus are different from those found on asteroids, comets, Mars and Earth. In fact, their composition is also different from each other, just like the rocks found on the different moons we visited, like Titan, the moon of Saturn.
The only rocks of which we can be certain of the common compositions are the rocks of the Earth and the rocks of the Moon. The similarity between terrestrial rocks and lunar samples implies a giant and early impact as the cause of the creation of the Moon.
Densities of various bodies in the solar system. Note the relationship between density and distance from the sun.Karim Khaidarov
For each rock of the Earth, whatever its origin, we can analyze what are the elements of the periodic table, as well as the reports of the isotopes of these elements.
For example, one of the great evidence that the great extinction event, 65 million years ago, came from an asteroid is a thin layer of ash dating from around the world, where the ash contains about 10 times the density of iridium. found in rocks on the earth. This is a common phenomenon among asteroids, which is why we consider it to be the main cause of the disappearance of dinosaurs and the growth of mammals.
The Cretaceous-Paleogene boundary layer is very distinct in sedimentary rocks, but it is the thin layer of ash and its elemental composition that tells us the extraterrestrial origin of the impactor that caused the 39; mass extinction.James Van Gundy
The objects that arrive on Earth are, however, in a special class. Rather than finding them in space, they cross the solar system and collide with our world, where many of them fall to the surface and leave leftovers. These meteorites come in a variety of types. They have different densities, different elemental abundances and different geological characteristics within them. Most meteorites are stony and contain small round particles consisting mainly of silicon in the interior. These types of meteorites, known as chondrites, account for about 86% of all meteorites. 8% more are stony, but without these silicate particles melted inside: the achondrites. Finally, the remaining 6% are iron meteorites, a mixture of rock and metal.
A chondrite H from northern Chile shows chondrules and metallic grains. This meteorite is rich in iron and is the most common type found today.Randy L. Korotev of the University of Washington at St. Louis
But even if it includes all the meteorites we've ever found, they are not all created in the same way, or even generally. Some of them, as far as their composition goes weirdos. In particular, three different types are distinguished:
- Shergottites: These are volcanic rocks, rich in magnesium and iron, with a variety of sizes of crystals and minerals inside, and they seem to have crystallized recently, maybe there is only 180 million years.
- Nakhlites: they are much older and formed between 1.3 and 1.4 billion years ago, also because of volcanic activity. They are rich in mineral augite and contain traces of liquid water about 620 million years ago.
- Chassignites: These meteorites are almost exclusively made up of mineral olivine, with pyroxene, feldspar and inserted oxides. It contains noble gases of different composition of the Martian atmosphere, which favors an origin in the mantle of the planet.
The Martian meteorites Shergottite (R) Nakhlite (C) and Chassignite (L) are posted on October 21, 1996 in New York. The Shergottite meteorites are by far the most widespread of Martian origin, comprising about 80% of the Martian meteorites found on Earth. (JON LEVY / AFP / Getty Images)
These three types are significantly different from all other meteorites found on Earth, but have elementary and isotopic commonalities. The ratio of their oxygen isotopes, in particular, was different from that of other meteorites, as was their younger training age. For a long time scientists have suspected that they could have a common origin to each other, distinct from the most typical meteorites.
In 1976, Viking landers provided direct information on the Martian surface, including the Martian atmosphere and rocks found on the ground. The similarities were striking, which led many to speculate that all three types came from Mars. But the real "smoking rifle" appeared in 1983, when a variety of trapped gases were found in the glass formed by the impact of such a shergottite, and it corresponded to gas found by Viking on Mars.
Landing on the Martian surface in July 1976, this image of Mars dated July 24 is, in the image, one of the first images of the Martian surface as it would appear in the eyes of man.NASA / Viking 1
In 2018, there are 207 known Martian meteorites. On the basis of radiometric dating, we can conclude that the meteorites originating in Mars are extremely young: only three of them, originating in Mars, are more than 1.4 billion years old, the majority of them Being formed a few hundred million years ago.
In addition, we can say how long they have been traveling based on their exposure to cosmic rays, which range from about 730,000 years to about 20 million years ago.
All that created these formations on Mars has occurred relatively recently, geologically speaking, and whatever the ejected impacts, they occurred after the mammals had already dominated the Earth.
Meteor, photographed above the Atacama Large Millimeter / sub-millimeter array Array, 2014. About 0.3% of the meteors that leave meteorites on the Earth's surface come from Mars.ESO / C. Malin
There is no impact of the magnitudes of dinosaur destruction to eject material from a planet, and these impacts occur often enough to diffuse materials from one planet to another in a solar system. About 0.3% of all meteorites that fall on Earth have a Martian origin, which suggests that life can spread from one world to another, even in a solar system, if conditions permit. No humans have yet traveled to another planet, but thanks to the natural and violent processes inherent in the presence of asteroid belts and comets, other planets arrive regularly. There are pieces of Mars found all over the world. If we pay attention, we could simply find evidence of the Earth – including the possibility of a life originating on Earth – on worlds that we still have to visit.
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Mars, with its thin atmosphere, photographed from the Viking orbiter in the 1970s. The bright red atmosphere is due to the presence of Martian dust in the atmosphere and the composition of the rocks of Mars was discovered for the first time by viking landers.NASA / Viking 1
As the planets revolve around the Sun, well separated from each other, we tend to assume that they do not exchange hardware very often. The solar system can be a violent place, marked by asteroid strikes and cometary collisions, but the planets themselves are too large and massive to be affected by these phenomena. When large energy collisions have an impact on your planet, the worst, in general, is to create a crater and cover your world with debris.
The Meteor crater (Barringer), located in the Arizona desert, is more than 1.1 km in diameter and only represents an energy release of 3 to 10 megaTons. An asteroid attack of 300 to 400 meters would release 10 to 100 times more energy and could be large enough to send fragments of the Earth into space, ejecting from our world where she could travel to other places in the solar system.USGS / D. Roddy
But sometimes, if the impact is large enough, it can cause debris in space. Many moons of our solar system – including the moons of Earth, Pluto and Mars – were created from the coalescence of these debris after a giant impact. Part of the debris falls back on the planet, while the remaining materials are completely ejected from the planetary system.
In theory, materials from one planet can be transferred to another.
In practice, we know that this is true. Pieces of Mars have been found on Earth, and new ones are falling into our world every two or three years.
Structures on the meteorite ALH84001, of Martian origin. Some argue that the structures shown here may be an old Martian life, but others argue that it is simply a non-biogenic magnetite that could have a purely geochemical origin.NASA, 1996
The science of meteorites is fascinating, with more than 61,000 pieces of confirmed rock of alien origin found on Earth. The solar system is a diverse and complex place, and every body on which we landed or sampled is different from each other. The surface rocks on Venus are different from those found on asteroids, comets, Mars and Earth. In fact, their composition is also different from each other, just like the rocks found on the different moons we visited, like Titan, the moon of Saturn.
The only rocks of which we can be certain of the common compositions are the rocks of the Earth and the rocks of the Moon. The similarity between terrestrial rocks and lunar samples implies a giant and early impact as the cause of the creation of the Moon.
Densities of various bodies in the solar system. Note the relationship between density and distance from the sun.Karim Khaidarov
For each rock of the Earth, whatever its origin, we can analyze what are the elements of the periodic table, as well as the reports of the isotopes of these elements.
For example, one of the great evidence that the great extinction event, 65 million years ago, came from an asteroid is a thin layer of ash dating from around the world, where the ash contains about 10 times the density of iridium. found in rocks on the earth. This is a common phenomenon among asteroids, which is why we consider it to be the main cause of the disappearance of dinosaurs and the growth of mammals.
The Cretaceous-Paleogene boundary layer is very distinct in sedimentary rocks, but it is the thin layer of ash and its elemental composition that tells us the extraterrestrial origin of the impactor that caused the 39; mass extinction.James Van Gundy
The objects that arrive on Earth are, however, in a special class. Rather than finding them in space, they cross the solar system and collide with our world, where many of them fall to the surface and leave leftovers. These meteorites come in a variety of types. They have different densities, different elemental abundances and different geological characteristics within them. Most meteorites are stony and contain small round particles consisting mainly of silicon in the interior. These types of meteorites, known as chondrites, account for about 86% of all meteorites. 8% more are stony, but without these silicate particles melted inside: the achondrites. Finally, the remaining 6% are iron meteorites, a mixture of rock and metal.
A chondrite H from northern Chile shows chondrules and metallic grains. This meteorite is rich in iron and is the most common type found today.Randy L. Korotev of the University of Washington at St. Louis
But even if it includes all the meteorites we've ever found, they are not all created in the same way, or even generally. Some of them, as far as their composition goes weirdos. In particular, three different types are distinguished:
- Shergottites: These are volcanic rocks, rich in magnesium and iron, with a variety of sizes of crystals and minerals inside, and they seem to have crystallized recently, maybe there is only 180 million years.
- Nakhlites: they are much older and formed between 1.3 and 1.4 billion years ago, also because of volcanic activity. They are rich in mineral augite and contain traces of liquid water about 620 million years ago.
- Chassignites: These meteorites are almost exclusively made up of mineral olivine, with pyroxene, feldspar and inserted oxides. It contains noble gases of different composition of the Martian atmosphere, which favors an origin in the mantle of the planet.
The Martian meteorites Shergottite (R) Nakhlite (C) and Chassignite (L) are posted on October 21, 1996 in New York. The Shergottite meteorites are by far the most widespread of Martian origin, comprising about 80% of the Martian meteorites found on Earth. (JON LEVY / AFP / Getty Images)
These three types are significantly different from all other meteorites found on Earth, but have elementary and isotopic commonalities. The ratio of their oxygen isotopes, in particular, was different from that of other meteorites, as was their younger training age. For a long time scientists have suspected that they could have a common origin to each other, distinct from the most typical meteorites.
In 1976, Viking landers provided direct information on the Martian surface, including the Martian atmosphere and rocks found on the ground. The similarities were striking, which led many to speculate that all three types came from Mars. But the real "smoking rifle" appeared in 1983, when a variety of trapped gases were found in the glass formed by the impact of such a shergottite, and it corresponded to gas found by Viking on Mars.
Landing on the Martian surface in July 1976, this image of Mars dated July 24 is, in the image, one of the first images of the Martian surface as it would appear in the eyes of man.NASA / Viking 1
In 2018, there are 207 known Martian meteorites. On the basis of radiometric dating, we can conclude that the meteorites originating in Mars are extremely young: only three of them, originating in Mars, are more than 1.4 billion years old, the majority of them Being formed a few hundred million years ago.
In addition, we can say how long they have been traveling based on their exposure to cosmic rays, which range from about 730,000 years to about 20 million years ago.
All that created these formations on Mars has occurred relatively recently, geologically speaking, and whatever the ejected impacts, they occurred after the mammals had already dominated the Earth.
Meteor, photographed above the Atacama Large Millimeter / sub-millimeter array Array, 2014. About 0.3% of the meteors that leave meteorites on the Earth's surface come from Mars.ESO / C. Malin
There is no impact of the magnitudes of dinosaur destruction to eject material from a planet, and these impacts occur often enough to diffuse materials from one planet to another in a solar system. About 0.3% of all meteorites that fall on Earth have a Martian origin, which suggests that life can spread from one world to another, even in a solar system, if conditions permit. No humans have yet traveled to another planet, but thanks to the natural and violent processes inherent in the presence of asteroid belts and comets, other planets arrive regularly. There are pieces of Mars found all over the world. If we pay attention, we could simply find evidence of the Earth – including the possibility of a life originating on Earth – on worlds that we still have to visit.
