The collision of stones with the Earth's atmosphere causes amazing light phenomena that reach the surface about 17,000 times a year. The latter are called meteorites. Based on direct tests, these objects are almost identical, made of similar materials and have been fried by cosmic radiation for a similar short time.
According to three studies recently published by the French National Center for Scientific Research, the European Southern Observatory, and Charles University in the Czech Republic, 70% of meteorites can be traced back to three families of asteroids. It was formed in three recent cosmic collisions, 5.8 million, 7.5 million and 40 million years ago. The researchers also studied the origin of additional meteorites, so 90 percent of them are known.
Meteorites can be divided into three main groups: stony meteorites, iron meteorites, and iron stony meteorites. There are also two main groups within stony meteorites: ordinary chondrites, whose internal composition shows spherical molten droplets (85 percent of meteorites on Earth are like this), and there are also carbonaceous chondrites, whose material is clay-water and has never melted. . Ordinary chondrites are classified into H, L, and LL classes based on their iron and magnesium content.
Most of the asteroids in the solar system are located in the belt located between the orbits of Mars and Jupiter. Jupiter, the largest planet in the solar system, interferes in their lives, and with its enormous gravity disturbs their orbits and causes collisions. On the inner side of the belt, stony meteorites are more common, while on the outer part there are more carbonaceous types of chondrites.
Family wreck
According to the researchers, based on telescopic observations and computer modeling, the source of the debris colliding with the Earth is three families of asteroids: Massalia, Karen, and Coronis.
The oldest one, Massalia, formed 466 million years ago in a collision, followed by another 40 million years ago. From this family come L chondrites, which occur in Swedish Ordovician limestone.
The Corones family formed 7.6 million years ago, while the Karen family resulted from a collision 5.8 million years ago. H-chondrites are derived from these.
In each case, the emerging orbs were larger than 30 kilometers in diameter. After the collision, small pieces of the large amount of debris have a greater chance of escaping the collective gravity of the belt, so they can also reach the interior of the solar system.
The researchers were able to trace another 20% of the meteorites to three other families: the Veritas, Polana, and Eos asteroids. According to their announcement, work will continue to search for the origin of additional types of meteorites. These are palalacites, which belong to iron meteorites, and stony and iron meteorites, and ureilites, which belong to achondrites.