A meteorite is a type of material from cosmic space, usually fragments of an asteroid or comet. When these celestial bodies meet Earth, their speed is very high, potentially reaching tens of kilometers per second or even higher. This high-speed collision generates a huge amount of energy, causing the celestial body to shatter and release a large amount of heat and gas.
Some of these debris will enter the Earth's atmosphere and rub violently against the air. This friction creates high temperatures that melt the surface of the meteorite and form a bright fireball, which is what we commonly refer to as a meteor. If the meteor does not burn up completely, it will fall to the Earth's surface in the form of a meteorite.
Most of the meteorites come from the asteroid belt, a region between Mars and Jupiter where a large number of asteroids and comets are present. These celestial bodies may collide during their orbit, creating debris and being attracted towards Earth by gravity.
In addition, some meteorites may also come from galaxies outside the solar system. These interstellar materials may collide with other celestial bodies during a long cosmic journey and change their orbits, eventually entering the solar system and falling to Earth.
In conclusion, meteorites falling from the sky are caused by the movement and collision of celestial bodies in the universe. These meteorites provide us with important clues to study the origin of the solar system and the universe, and are of great significance for understanding the evolution of the universe and the formation process of the earth.