What Is an Achondrite?
Meteorites are also called "meteorites", which are unburned stone, iron, or stone-iron mixed materials that are scattered from the original orbit of the universe, or fragments of dust from the original orbit.
- Because meteorites are from outer space, determining the authenticity of meteorites requires instrumental identification, and the naked eye has only an auxiliary role. Most meteorites come from between Mars and Jupiter
- By observing some gravel-encrusted meteorites, we understand that the space environment when small celestial bodies evolve in space is: there are a large number of small celestial bodies orbiting the sun. The diameter of these small celestial bodies is as large as tens of kilometers, hundreds of kilometers , As small as tens of centimeters, several centimeters, or even smaller, like the size of pebbles and sand particles. Small celestial bodies often collide with each other during operation. Generally speaking, small celestial bodies with a size of more than ten centimeters are hit by thousands, tens of thousands of gravel or sand particles.
- Because these small celestial bodies travel in space at cosmic speed, they are much faster than the speed of travel of guns and cannonballs. Therefore, the impact force produced by the small celestial bodies colliding with each other is very large. Under the action of this impact force, high temperature and pressure will be generated on the collision surfaces between small celestial bodies, and the mineral rocks will be melted and metamorphic to form a molten body. The shape of this melt is diverse. In a nutshell, the metamorphic melts left on the outer surface of the small celestial body are the small shell's melting shell, crater and melting tank. The metamorphic melts left inside the small celestial bodies are the walls of molten caves and melting zones. Through observation of the meteorite, it is found that the thickness of the molten shell constructed by each impact is generally between 1 mm and 10 mm.
- When a small celestial body is hit by thousands of gravel or sand dust particles, a large number of local small melts will be superimposed to form the outer shell of the small celestial body. Generally speaking, the greater the impact force, the larger the molten mass produced, and the thicker the shell of the small celestial body that is built. Usually the shells of small celestial bodies we see on meteorites are several millimeters or more in thickness. Take a look at the large meteorite in Xinjiang, the thick shell was built after the impact of thousands of gravel and sand particles.
- Collisions between small celestial bodies often change their internal structure and structure. For example, the spherulite structure will be changed to a spherulite structure. Of course, the spherulite structure can also be changed to a spherulite structure. Meteorites are small celestial bodies that fall to the ground. When it passes through the earth's atmosphere, it has strong friction with the air. Under the action of high pressure and high temperature, its appearance often melts and deteriorates. After cooling, a molten shell with a thickness of about one millimeter is produced on the surface of the meteorite.
- Generally speaking, there are two types of molten crust in the same meteorite, one is the molten crust produced by collisions between asteroids in space, and the other is the molten crust produced by friction between the earth and the atmosphere.
- To determine whether a sample is a meteorite, consider the following:
- 1. Appearance of molten crust : Before the meteorite falls to the ground, it must pass through the dense atmosphere. During the landing process, the meteorite rubs with the atmosphere to generate high temperature, causing its surface to melt and form a thin molten crust. As a result, the surface of the newly landed meteorite has a black molten shell with a thickness of about 1 mm.
- 2. Surface air prints : In addition, due to the interaction between the meteorite and the air current, many air prints are left on the surface of the meteorite, just like a finger print pressed by a finger.
- 3 Internal metal : iron meteorite and stone iron meteorite are composed of metallic iron, and the iron has a high nickel content (5-10%). There are also metal particles inside chondrites, and small metal particles can be seen on the fresh fracture surface.
- Meteorites are generally divided into four categories according to the content of iron-nickel metal in them: stone meteorite, iron meteorite, stone iron meteorite, and glass meteorite. The iron-nickel metal content in the stone meteorite is 30% or less. The iron-nickel metal content of the stone iron meteorite is between 30% and 65%. The iron-nickel metal content of the iron meteorite is greater than or equal to 95%. Glass meteorite does not contain metals.
- Most meteorites are chondrites (accounting for 91.5% of the total), of which ordinary chondrites are the largest (80% of the total). Chondrites are characterized by a large number of millimeter to sub-millimeter silicate spheres inside (see picture). Chondrites are the most primitive matter in the solar system and are the products directly condensed from the original solar nebula. Their average chemical composition represents the chemical components of the solar system. The largest stone meteorite in the world is the ordinary chondrite meteorite that fell in Jilin Province of China in 1976. The No. 1 meteorite weighs about 1770 kg.
- Aspheric meteorite, stone iron meteorite and iron meteorite are collectively referred to as differentiated meteorite. They are the products of spherulitic meteorite that are differentiated and crystallized by melting at high temperature, and represent samples of different levels inside the asteroid. These asteroids have an internal structure similar to that of the Earth, with three layers and an iron core in the center (
- The more expensive meteorites in the world are the moon and Mars meteorites, about 6,000 US dollars, or 30,000 yuan per gram. Cheap desert meteorites have a high degree of weathering, which is 1 yuan per gram. If there are many witnesses when they fall The price is 40 yuan to 50 yuan per gram. At present, among all types of meteorites in China, the meteorites known as black sapphire are more valuable than the moon and Mars meteorites, because at present, humans cannot determine their origin, most likely from the planet generated during the Big Bang in the space beyond 15 billion light years. This is very useful for studying the boundaries and formation of the universe. During the process of crossing the atmosphere, it crashed into the desert of the earth after high-speed autobiography, so it is well preserved, the molten shell is relatively complete, the surface is bright, and the whole body is black and green. It has high collection and research value. One of the best-preserved 2750 grams of black sapphire meteorite in China was purchased by a mysterious collector in Beijing for 40 million yuan. The meteorite is not a moon or a Martian meteorite. The source of the meteorite is unknown. The world is only one piece. The value is over 60 million yuan, the unit price is more than 20,000 yuan per gram, and there is great room for appreciation in the future.
- "The domestic market generally has a state of distrust, and many people complete their purchases through international channels. Distrust is caused by too many domestic fake meteorites and by elevated prices," Rex said. Very fast, rare and well-selling high-end meteorite, the competition is becoming increasingly fierce, and has increased by 10 times in the past two years, while some ordinary meteorites have also increased by about 1 time. [6]
- At the end of November 2014, many domestic media quoted the Spanish "Abesai" as saying that the entry of the rich in China changed the "ecosystem" of the meteorite trade, which not only raised the price, but also exacerbated the trend of counterfeit goods in the meteorite market. . Some analysts say that some new buyers only care about how much the meteorite is worth, and they don't care about its scientific value at all. [6]
Muonionalusta Meteorites Muonionalusta
- A nickel-iron meteorite was discovered in Sweden in 1906 and named Muonionalusta.
- Seiko Watch has carefully crafted a craft called "Iron Arm Astronomical Meteorite Watch", the dial of this watch is made by slicing this meteorite with high technology. The cut surface of this meteorite has a natural and special texture called the "Vistaden structure". The pattern on the surface is fashionable and simple. This is a special feature that was formed once every million years when the planet cooled. Structure, namely octahedral crystal structure.
- Researchers at the University of Stuttgart, Germany, found a 1,000-year-old meteorological Buddha statue that weighs 10 kilograms and is about 24 centimeters high. In fact, a Nazi expedition discovered the statue of Buddha as early as 1938. Research has found that the statue is carved from a rare nickel-iron meteorite. The culture represented is believed to be somewhere between Buddhism and the pre-Buddhist Bon culture. The Buddha depicted is the Vishnu King, the northern king of Dover, which is called "Tibetara" in Tibet. The Iron Buddha is the only known human statue carved from a meteorite, and its value is inestimable.
- The statue was first discovered by a Nazi expedition in 1938. Studies have found that this statue of Buddha was carved from a meteorite
Meteorite crater
- More than 120 impact craters have been discovered on Earth, most of which were formed within 200 million years. In general, older ones are bigger. A crater near Sudbury, Ontario, Canada, has a diameter of 145 kilometers. It is about 1.8 billion years old. The only other crater of its age is in Fort Friedland, South Africa.
- Canada has most of the craters remaining on Earth, although only one is old. A crater in Lake Maniquagan, Quebec, is about 210 million years old. It is flooded with rain and has formed a lake of 74 kilometers in diameter. The diameter of the meteorite that caused this lake should be nearly 3000 Meter.
- The largest crater surviving on Earth comes from a recent period in the history of the solar system. The Ballinger crater in the Arizona desert was formed by an iron meteorite impact about 30,000 years ago. It is estimated that the iron meteorite has a diameter of 60 meters and a mass of more than 1 million tons.
- The largest meteorite that has not exploded in the world is much smaller than the ancient objects that formed some of the largest craters. The meteorite in the Houtabas of Namibia in southwestern Africa weighs 60 tons and has a volume of 2.75 meters by 2.75 meters by 1 meter. It may have fallen to Earth thousands of years ago, but no crater was left. The only logical explanation is that it approached the Earth at a small angle, causing it to move much faster than usual.
Meteorites and paleontological extinction
- Scientists believe that the huge meteorite that fell to the earth about 66 million years ago caused the extinction of many animals and plants on the earth. This meteor, estimated to be 10 kilometers in diameter, hit the earth in the late Cretaceous, which led to the sudden extinction of dinosaurs. These giant reptiles ruled the earth for millions of years and in the third The Midlands gave way to small mammals.
- The earth of that era is unusually rich in iridium. This material is rare on Earth, but it is abundant in meteorites, so the iridium in the clay is believed to have been released by this huge meteorite impact.
- Huge meteorites can cause the extinction of species in many ways. If it falls into the ocean, it can cause a tsunami, with huge tidal waves reaching up to 100 meters. Some studies have shown that the marine alluvium is consistent with the passage of the giant waves at this time.
- Impact can also throw large amounts of matter into the atmosphere. This will block the sun's light, hinder the growth of plants, and then affect animals that feed on plants. Scientists know that 70% of the species were extinct at that time. A large range of coal ash fossils, mineral particles with strong impact characteristics, and small spheres of molten rock were also found during the Cretaceous and Tertiary boundary periods. Huge meteorites can create craters 40 kilometers deep, which is deep enough to penetrate the crust of the ocean or the continent, resulting in a large number of volcanic eruptions.
- Either the Sudbury crater in Canada or the Friedrichburg crater in South Africa has evidence that it has caused a volcanic eruption. Large-scale volcanic activity can directly lead to the extinction of many species. Large-scale volcanic eruptions will increase the amount of dust in the atmosphere. First, the climate will continue to cool for a period of time, then gradually lead to the corresponding global destructive climate warming, and finally fatal acid rain.
- We all know that dinosaurs were a large-scale reptile in ancient times. If they did not become extinct in the late Mesozoic, then the ancient apes in the obscure era would have at least no chance to become modern humans. So how did dinosaurs become extinct? Scientists have discovered that in the Cretaceous-Third Boundary Sediment, a layer of white powder with a thickness of several tens of miles was deposited, which is an extremely rare amino acid on the earth. Therefore, they reasoned: 65 million years ago, a meteorite with a diameter of about 10 kilometers collided with the earth. The huge explosion after the impact caused most dinosaurs to die immediately. The powder after the explosion shrouded the earth. The sudden change caused none of the dinosaurs to survive, but the extinction of the dinosaurs brought vitality to other newborn animals, such as the emergence of mammals, and the ancient apes were forced out of the forest.
- Meteorites contributed to the production of human beings, and the impact of meteorites promoted the production of living things. Evolution, development, but meteorites can also be harmful to humans. For example, Great Western Continent, an ancient civilization continent submerged on the bottom of the Atlantic Ocean, because it is on the edge of the Atlantic crater mentioned above. The ancient Indians who created the splendid Mayan culture suddenly disappeared because they often had Meteorites appear?
- In today's evolving world, outside is a world full of magic, but also full of danger. For example, on March 23, l989, an asteroid equivalent to the power of several thousand Hiroshima atomic bombs passed by with the earth. Its next visit will be in 2015. Whether it will collide at that time can only be proved by facts. But we can't let the past tragedy repeat itself and wait and see, let's hurry up all the time to understand it and conquer it until we use it. I believe it will happen in the near future.
Top Ten Meteorites
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