A fireball is a fairly rare phenomenon-a fireball flying through the sky. This phenomenon is caused by the intrusion into the dense layers of the atmosphere of large solid particles called meteor bodies. (And the remnants of meteor bodies that have fallen to Earth are called meteorites.) Moving in the atmosphere, the particle heats up due to braking, and a vast luminous shell consisting of hot gases is formed around it. Cars often have a noticeable angular diameter and are visible even during the day.
The car passes within a few seconds, and the trail left by it can be observed for tens of minutes or even more than an hour. It continuously changes its shape, bends in all directions, and then breaks apart. The reason for this phenomenon is a hurricane wind, which always blows in the upper atmosphere. The wind blows and breaks the track of the car.
During the flight of the car, the area is illuminated by a bright flashing light. Sometimes, especially when flying a bright and large car, a few minutes after its disappearance, a rumble with peals is heard, since the strong air resistance often splits the meteor body and falls to the Ground with a crash in the form of fragments. In remote times, the flight of fireballs caused superstitious fear among the people. The fireballs, with their fiery tails and writhing tracks, were mistaken by superstitious people for fire snakes or dragons.
Perhaps the most famous fireball of our time can be considered the Sikhote-Alin meteorite.
A meteor body, which is small in size, sometimes completely evaporates in the Earth’s atmosphere. In most cases, its mass is greatly reduced during the flight, and only the remnants reach the Earth, usually having time to cool down when the cosmic speed is already extinguished by air resistance. Sometimes a whole meteor shower falls. When flying, meteorites are melted and covered with a black crust. One such “black stone” (Kabbah) in Mecca is embedded in the wall of the temple and serves as an object of religious worship.
Meteorites – stone or iron bodies falling to the Earth from interplanetary space; they are the remains of meteor bodies that did not completely collapse when moving in the atmosphere.
It says here how to find out a meteorite.
Meteorites can fall out in cases where the speed of a meteor body that has invaded the Earth’s atmosphere does not exceed 22 km/s and if this body has sufficient mechanical strength. Meeting the resistance of the air, the meteor body is slowed down, its kinetic energy is converted into heat and light. As a result, the surface layer of the meteorite and the air shell formed around it are heated to several thousand degrees. The substance of the meteor body after boiling evaporates, partially sprayed into the smallest droplets. Falling to the Ground almost vertically, the fragments of the meteor body cool down and when they reach the ground, they are only warm. They are covered with a solidified melting crust. In the place where meteorites fall, depressions are formed, the size and shape of which depend on the mass of the meteorites and the speed of their fall.
The largest meteorite was found in South-West Africa in 1920. This meteorite, called Goba (the names are given for the locality closest to the crash site), is iron, its mass is about 60 tons. Such large meteorites rarely fall. As a rule, the mass of meteorites is hundreds of grams or several kilograms.
The largest meteorites also include the iron Sikhote-Alinsky (which was already mentioned above), which fell in the USSR in 1947. It split into thousands of pieces in the atmosphere and fell to the Ground in an “iron rain”. When it hit the ground, parts of the meteorite shattered the rocks, forming craters and craters in them. 200 craters and craters with a diameter of 20 cm to 26 m were found. The mass of the Sikhote-Alin meteorite is estimated at 70 tons, more than 23 tons have been collected.
Meteorites are made up of the same chemical elements that exist on Earth. These are basically the following eight elements: iron, nickel, magnesium, silicon, sulfur, aluminum, calcium, and oxygen. The remaining elements are found in meteorites in very small amounts. Combining with each other, these elements form various minerals in meteorites, most of which are also present on Earth. But there are also meteorites with minerals unknown on Earth.
Iron meteorites consist almost entirely of iron in combination with nickel and a small amount of cobalt. In stony meteorites there are silicates-minerals that are compounds of silicon with oxygen and an admixture of other elements (magnesium, aluminum, calcium, etc.). It is found in stony meteorites and nickel iron in the form of grains scattered throughout the mass of the meteorite. Ironstone meteorites consist of almost equal amounts of stony matter and nickel iron.
If you look at the fracture of a stone meteorite, you can see rounded particles-chondrums. They are shaped like balls with a diameter of 2-5 mm. In different places of the Earth, tektites were found – glass pieces of small size, weighing several grams. Currently, it is established that tektites are frozen splashes of terrestrial matter, thrown out (sometimes over huge distances) during the formation of meteorite craters.
It is estimated that about 100 tons of meteor material falls on the Earth per day.
Meteorites are traditionally considered a threat to life on our planet. Scientists carefully track the trajectories of celestial bodies approaching the Earth and calculate the chances of a collision. However, as it turns out, it is quite possible that it was thanks to them that the Earth at one time turned into a habitable planet.
Canadian geologists say that it is extremely likely that the development of organic life on the planet was stimulated by living organisms brought to Earth as a result of a strong meteor shower. This conclusion allowed them to make a study of one of the meteorite craters dating back to the Devonian period (410 million to 350 million years ago).
This crater, formed many millions of years ago from the impact of a large meteorite on the Earth’s surface, contains hydrothermal systems that could be a convenient place for the survival and reproduction of microorganisms brought by the celestial body from space.
The scientists said that if further research confirms their conclusions, the meteorite craters of this geological period can become an excellent object for studying the origin of life not only on Earth itself, but also will open the veil of mystery over previously existing life forms on other planets of the Solar System, for example, on Mars.
The researchers also advocate the rejection of the widespread theory that meteorites once caused the extinction of the dinosaurs on Earth. They argue that this approach needs to be seriously revised and people should stop perceiving meteorites solely as a threat to life on the planet.
The head of the research team emphasizes the importance of the current study of meteorite craters and the microorganisms that lived in them in the light of the theory of the origin of life on Earth as a whole. He says that when studying this issue, it is impossible not to take into account the fact that the first period of the process was accompanied by constant meteor showers.
It is, of course, easy for scientists to reason in this way. However, it is unlikely that ordinary people will be able to calmly take the possibility of a large meteor shower. After all, none of us wants to pay with our own lives for the emergence of new forms of life on Earth.