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Meteorite - a solid body of cosmic origin, that on the surface of the Earth. Most meteorites are found from the weight of a few grams to several kilograms. The largest of the meteorites found - Goba. Its weight is estimated to have amounted to about 60 tons Scientists believe that a day on Earth falls 5-6 tons of meteorites, or 2000 tons per year. 

By April 2010 were more than 1087 meteorites falling to Earth's atmosphere or found on the surface of the planet. 
The cosmic body to hit the Earth's atmosphere called the meteoric body and is classified by astronomical signs. For example, it may be a cosmic dust, meteoroids, asteroids and their fragments or other meteoroids. Flies through Earth's atmosphere and leaving it in a bright glowing trail, regardless of whether it will fly in the upper atmosphere and goes back into space, a burn in the atmosphere or falls to Earth, can be called either a meteor or a fireball. Meteors are not brighter than the body of the 4th magnitude, and fireballs - brighter than 4th magnitude, or a body whose angular dimensions are distinguishable. 

At the crash site of a large meteorite crater can be formed (astrobleme). One of the most famous craters in the world - Arizona. It is assumed that the largest impact crater on Earth - the Wilkes Land crater (diameter about 500 km). 

Meteoroid enters the Earth's atmosphere at speeds of 11 to 72 km / s. At this speed, it begins to warm up and glow. Due to ablation (burning and blowing away the oncoming stream of particles of matter of a meteoric body) body weight, managed to fly up to the surface, may be smaller, and in some cases significantly less than its weight on the entry. For example, a small body, which became part of the Earth's atmosphere at a speed of 25 km / s or more, burns with almost no residue. At such a speed re-entry of tens and hundreds of tons of the initial mass floated to the surface only a few kilograms or grams of material. Traces of burning meteoroid in the atmosphere can be found throughout most of the trajectory of his fall. 

If the meteoroid does not burn in the atmosphere, to the extent of inhibition, it loses its horizontal velocity component. This leads to a change in the trajectory of the fall, often, almost horizontal at the beginning to almost vertical, in the end. As the brake, the glow of meteoroid falls, it cools (often suggest that the meteorite in the fall was warm, not hot). 

In addition, it may cause destruction of the meteor body into fragments, which leads to loss of a meteor shower. 



Автор: admin от 03.03.2012



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