What are meteorites?
- Pieces of rock or iron that fall to earth from space. Many thousands fall to earth each year, mostly landing in the ocean, but significant numbers fall onto the continents.
- Mostly derived from the asteroid belt, where fragments are knocked out of orbit, eventually intersecting with the earth. A much smaller number are derived from the Moon and from Mars as the result of large collisions.
- Classified as either falls or finds. Falls are those recovered after being observed to fall to earth. A famous Queensland example is the 1879 Tenham meteorite shower, of which over 300 stones have been collected. A find is a meteorite discovery without the observation of a fall.
Meteorites have been found in many places in Australia. Most have been found in the desert and drier areas of the continent where they are easily seen without the vegetation cover.
Meteorites found in Australia may not be exported without a permit.
Types of meteorites
Iron meteorites are mostly made of nickel rich metallic iron and are believed to come from the cores of broken up asteroids. They contain few silicate minerals, and are very heavy. There are many different classes of iron meteorite.
Stony meteorites are meteorites rich in silica minerals such as olivine and hypersthene. They contain small amounts of metal. They are lighter in weight then iron meteorites. There are a large number of classes of stony meteorites.
Stony-iron meteorites have approximately equal amounts of iron and silicate minerals which make for very attractive meteorites. Again, there are many different types of stony-iron meteorites.
The study of meteorites is call meteoritics. Most, but not all meteorites are billions of years old. Their study can provide a great deal of information on the origin of the solar system and the formation of the earth itself.
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