Meteorites are rocks from space, which land on Earth, attracted by her gravity. The shooting stars that you see at night, are actually burning meteors that fall on Earth from outer space! This is the first of many interesting facts that are going to follow. Why do meteorites fall? For the same reason why anything falls on Earth - 'Gravity'. Very few can escape it! Meteorites have their origin in outer space. They are relatively small pieces of dust and debris, usually left behind in the wake of a comet. Meteorites, that are huge in size, have their origin in space, as asteroids. They are left over pieces of matter from formation of the solar system, which could not clump together to form a planet like our Earth. There is a dense belt of such asteroids outside the orbit of the planet Mars, called the 'Asteroid Belt'. Asteroids are huge in size and their lengths can number to kilometers! Once in a while, small pieces of rock or dust, come into range of Earth's gravitational pull and fall on Earth as shooting stars. An asteroid dislodged from its trajectory and falling on Earth is also called a meteorite. However, an asteroid being huge in size, causes a cataclysmic explosion on Earth on impact.
'Meteor' and 'Meteorite' facts are interchangeable terms and we shall see why they are so. When these rocks and pieces of dust are floating in space, they are called 'Meteoroids'. When they make a blazing entry into Earth's atmosphere, they are called 'Meteors'. Finally, if they survive the burning entry into Earth's atmosphere and fall on Earth, they are called 'Meteorites'. So a meteorite could originate from comet debris called meteoroids or larger objects called asteroids! Here are some basic facts about meteorites, meteors and meteoroids. Comets leave tons of dust and debris in their trail as they travel along long orbits round the Sun. When Earth, while revolving around the Sun, passes through some patches of this comet debris, it enters the Earth's atmosphere causing meteor showers. Meteor showers are periodic events. One can see thousands of meteors or shooting stars, as they are called, during such a shower. The most popular meteor showers are 'Perseids' (which peak around August 12) and Leonids (which peak around 17 November). During these showers, you can observe a shooting star at the rate of 1 meteor per minute on an average. A falling meteor can travel at speed of as much as 44 miles per second ! One of the facts is that they have some of the oldest rocks in the solar system among them. They could be older than the Earth and date from the period when Sun was forming! Every day, about 4 billion meteoroids fall on Earth! Majority of them are very tiny and therefore do not cause much harm. If a meteorite is observed while falling and recovered from the place of fall, it's called a 'fall' meteorite. If a meteorite is not observed while falling, but found from any location, it's called a 'find.' Till 2006, there have been roughly 1,050 witnessed falls while there are about 30,000 documented 'Finds'. Falling meteors which are large in size, can create an intense electromagnetic pulse, which temporarily disrupt radio communication in the region of fall! With a properly designed radio antenna, you can actually 'hear' meteorites falling as radio noise. Types and Composition
Here are some facts about their types and composition, that you should know about. Recovered meteorites are classified into three main categories which are 'Chondrites' (Make about 86% of all recovered meteorites), 'Achondrites' (8%) and 'Iron' meteorites (6 %). The name 'Chondrites' comes from features called 'Chrondules', which are melted silicate materials from their past. Chondrites are about 4.55 billion years old and are the types of rocks from which our own planet formed! Certain chondrite meteorites fallen from outer space contain traces of amino acids and organic matter, bolstering the theory that life may have been planted on Earth! This...
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